1. Sign-up to become a member, and most of the ads you see will disappear. It only takes 30 seconds to sign up, so join the discussion today!
    Dismiss Notice

A Primer for Home Theater Newcomers

Discussion in 'Beginners, General Questions' started by Vince Maskeeper, Mar 10, 2002.

  1. John Garcia

    John Garcia Executive Producer

    Joined:
    Jun 24, 1999
    Messages:
    11,571
    Likes Received:
    25
    Trophy Points:
    0
    Location:
    NorCal
    Real Name:
    John
    First time Using DTS on my system and there is no sound when selecting DTS on a DVD. Dolby Digital and music are working though, why?

    All three of these things MUST be present and configured for DTS playback:

    1) Your receiver must be set to "Auto detect" or forced to DTS decoding.

    2) In your DVD player's digital audio setup menu (NOT the menu on the DVD itself), you must ENABLE DTS. Dolby digital is on by default, and on 99.9% of players, DTS is NOT turned on from the factory. If there is an option for "bitstream" vs PCM, select bitstream.

    3) Select the DTS track in the DVD's setup/language selection menu.

    NOTE: Not having your DVD player setup correctly when selecting a DTS track may cause a "static" white noise that could damage your speakers.
     
  2. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    What the heck is a Laserdisc?

    Laserdisc was a disc-based audio/video format that preceded DVD. The discs, which you've probably seen on TV or in movies at some point, were larger than DVD (12 inches across, the same size as LP record albums). They were usually silver, and looked a lot like a giant DVD or CD.

    Laserdisc was similar to DVD in that it offered CD-like non-linear navigation (the ability to skip around quickly), high quality video and digital sound.

    We have Laserdisc to thank for many of the great features of DVD. Laserdisc was the first home video format to offer:
    1) Digital Sound
    - Regular 2-channel stereo audio on laserdisc was uncompressed digital, just like CD- providing excellent audio fidelity... many people prefer uncompressed LD audio to 2-channel DVDs.
    - Laserdisc was the first home video format to offer dolby digital 5.1 audio.
    - Laserdisc was also the first home video format to offer DTS 5.1 audio (and all DTS laserdiscs were full bitrate, where DTS DVDs are often a half bitrate DTS format).

    2) Special Editions & Extras
    - Laserdisc was the first format with alternate soundtracks, allowing running audio commentaries.
    - The image gallery and promotional stills gallery was also first popularized on laserdisc.
    - Deleted scenes were first widely incorporated into "special edition" laseridscs.
    - Pretty much the whole idea of a special edition or a collectors edition came directly from the laserdisc world, as it was mostly an appealing format for film collectors.

    3) Widescreen and OAR presentations
    - Again, because Laser was a collectors format, the majority of laserdiscs were presented in their OAR (original aspect ratio) format.


    So, Laserdisc really paved the way for DVD to exist in the first place. The original customer base for DVD was mostly made-up of previous laserdisc collectors. In the first few years when DVD really caught fire, it was film collectors making the jump from Laserdisc that really drove sales. Some of the most popular early DVD players were combination DVD/Laserdisc players!

    Many serious HT buffs still have large LD collections, and still spend thousands of dollars on high-end laserdisc players.

    In the end, the popularization of DVD essentially killed the laserdisc format. While Laser certainly had many advantages, the fact that discs held (at most) 60 minutes per side- meant that most films required a side flip, or worse- switching discs in the middle of the film. Couple that with the fact that DVD offered cheaper discs, cheaper players and better video quality (Laserdisc can look quite good, nearly as good as DVD- but often you can only get the best Laser picture out of super-high end players)... the Laserdisc market slowly died as DVD gained popularity.


    Technically, LASERDISC releases of new films are no longer being produced for the US as of the late 1990's... however there are tons of discs available on Laser that are not (and may never be) available on DVD. One prime appeal for HT buffs is the availability of the ORIGINAL UNALTERED Star Wars trilogy on Laser (and rumor has it, Lucas will only be releasing the SE versions when they eventually come to DVD, so Laser might be the only opportunity to own a high quality, widescreen edition of the original films!).

    So, that is a basic introduction to laserdisc. If you're interested in the format- check out the excellent post in this thread from one of the HTF's resident Laserdisc fanatics, Rachael B:
    A complete guide to Laserdisc

    or check the HTF unofficial Laserdisc FAQ:
    http://www.hometheaterforum.com/htfo...threadid=26700

    or check Henrik Herranen's old 1998 Laserdisc Faq:
    http://www.cs.tut.fi/~leopold/Ld/FAQ/index.html

    -Vince
     
  3. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    What the heck is a DVD?

    DVD is one of the most recent, and most exciting additions the the world of home video! Actually, DVD can be used for Data, Movies and now even music-- but we'll concentrate on the DVD-video version for now...

    A DVD is a CD sized digital disc which contains audio and video. DVD offers a serious upgrade in terms of picture quality versus previous home video formats (like VHS for example), and offers digital sound (including the ability to play back theatrical surround sound formats like Dolby Digital and DTS!).

    A DVD works with video very much the same way a CD works with Audio. The disc allows you to access any point in the movie easily, and doesn't require rewinding like tape formats. DVD requires a special player (it doesn't play in a CD player).

    DVD has grown quite popular, both because of added quality of video and audio and because of special features available exclusive to DVD. Often, movies released on DVD will include:
    - A special audio track where you can listen to the director or the stars discuss the making of the film
    - Access to scenes that were removed from the film
    - Access to alternate endings to the movie which were filmed but not used.
    - Documentaries about the film production or special achievements of the film.
    - Tons more!

    In short, DVD can help you enjoy your favorite movies even more! Even better, DVDs usually cost around $20- so you can build a library of your favorites without breaking the bank!

    If you're new to DVD, you might want to check out Jim Taylor's excellent DVD Frequently Asked Questions, located here:

    http://dvddemystified.com/dvdfaq.html

    Here's what Jim had to say about what a DVD is:
     
  4. Jesse Leonard

    Jesse Leonard Second Unit

    Joined:
    Jun 8, 2000
    Messages:
    430
    Likes Received:
    0
    Trophy Points:
    0
    So, you just bought a DVD player (or a new TV) and want to show it off. The question in your mind is: What is a good DVD to show off my system?

    There are really two sides to this question. The first being the picture quality and the second being the sound quality.

    Picture Quality

    Excellent picture quality is one of the selling points of DVD, but you must keep in mind that just because a movie is available on DVD does not mean that the picture is going to be excellent. There are many things that affect how good a DVD will look on your TV. Some movies/television shows are shot on very low budgets and use very low quality film. Sometimes the original negative for a movie has been damaged. Some DVD production facilities are better than others. Some DVD transfers are done poorly, at too low of a bit rate or not done anamorphically. You get the idea; there are many things that can go wrong during the creation process of a DVD.

    Here are some titles that are generally acknowledged as being reference quality and are excellent discs to show off your display. There is something for everyone’s taste so chances are that you already own one of these.

    A Bug’s Life
    American Beauty
    Any Given Sunday
    Austin Powers: The Spy Who Shagged Me
    Citizen Kane
    Fight Club
    Gladiator
    Independence Day
    Lost in Space
    Moulin Rouge
    North by Northwest
    Shrek
    Starship Troopers
    Swordfish
    Titan A.E.
    The Fast and the Furious
    The Fifth Element - The SuperBit version (although the originally is very nice also)
    The Pledge
    The Rock – Criterion Collection
    The Straight Story
    Toy Story II
    Vertical Limit


    Sound Quality

    Just like the picture quality, there are many things that affect how good a DVD will sound. Older movies were not recorded with surround sound in mind, so although they may sound good, they may not be the best DVD to show off your speakers with. Some movies have very subtle soundtracks that do not rely on loud sounds. Newer, action based movies are normally chosen because of their special effects and explosions. Some people also prefer a DTS soundtrack over a Dolby Digital soundtrack.

    A Bug’s Life
    Aliens
    Apollo 13
    Cast Away
    Dances With Wolves – DTS
    Eagles - Hell Freezes Over – DTS
    Fight Club
    Gladiator
    Moulin Rouge
    Requiem For a Dream
    Saving Private Ryan – DTS
    Shrek
    Star Wars: Episode I
    Starship Troopers
    Terminator 2: Ultimate Edition
    The Fast and the Furious
    The Fifth Element - The SuperBit version
    The Haunting
    The Iron Giant
    The Matrix
    The Red Violin
    Titan A.E.
    Toy Story II
    U-571
     
  5. Jesse Leonard

    Jesse Leonard Second Unit

    Joined:
    Jun 8, 2000
    Messages:
    430
    Likes Received:
    0
    Trophy Points:
    0
    The DVD I bought/rented won’t play. Is my DVD player broken or is there a problem with the DVD disc?

    This question comes up almost every week. Although there is no single answer that will fit all situations, there are several things to check.

    First, if you rented the DVD then check the disc itself. Chances are that the surface of the disc is dirty or heavily scratched. If the disc is dirty then you can try cleaning it. There are many products on the market for cleaning a disc, but good ‘ol tap water, liquid dish soap and a soft clean towel will do the trick. If the DVD is heavily scratched then your only option is to return the disc to the place of rental and get another one (I always check for scratches before even leaving the rental store to save a trip).

    If the DVD was recently purchased, you should still check all of the above. If everything looks good then there are several possibilities. (It is always best if you can try to repeat the problem on another player. Go over to a friend’s house or try the DVD–rom in your computer. If it works there, then the problem is with your specific DVD player.) First, your DVD player may need cleaned. There are several cleaners available on the market. Secondly, there may be a problem (although this happens very seldom) with the authoring of the disc. DVD’s and DVD players are insanely complex. This, combined with the fact that there are hundreds of different types and brands of players, can cause incompatibility between certain discs and certain players. This does not happen very often, but check the Software section of this forum for other members who are having the same problem. Thirdly, it may just be a bad disc. There have been entire runs of DVD’s that have shown up flawed and sometimes it is just a few discs out of the batch. If you can’t get the disc to play properly in any DVD player then return it to the place of purchase to exchange it.

    Also, there is the problem of a DVD that has been in your collection for awhile and suddenly doesn’t play correctly. First, go through the steps above. If everything checks out then you may have a disc that has gone bad. This happens very rarely and the average consumer may never see this. If your DVD was recently purchased, you should exchange it at the place of purchase. If you are unable to exchange it then your only option is to contact the studio that issued the disc and ask for a replacement. This can be a long and frustrating task, but often times you will be allowed to exchange the defective DVD for a new one.

    Finally is the possibility that your DVD player is broken. Again, if it was recently purchased you should return it to the place of purchase. If it is still under warranty, then you could attempt to have it repaired at little to no cost to you (although it may take up to several months for them to return your player to you). If it is no longer covered under warranty then you could pay to have it repaired (which often times will cost more than buying a new player) or use this as an excuse to upgrade!
     
  6. Nate Anderson

    Nate Anderson Screenwriter

    Joined:
    Jan 18, 2001
    Messages:
    1,152
    Likes Received:
    0
    Trophy Points:
    0
    Special Edition and Bare-Bones 101

    Okay, we'll start off with Bare Bones DVDs since this should be a simple definition. A "Bare Bones" DVD is one that simply contains the film, a couple different audio options and maybe a trailer. Usually the cheaper titles fall in this catagory.

    Special Editions 101:

    It seems these days as though everyone is trying to out-do one another with the ultimate special edition. Each studio has their own "Premium Line" that includes their very best. I'm going to run down each each studio's line:

    20th Century Fox: Five Star Editon is their line of supreme special editions and they are top notch. Some of the titles included are M*A*S*H, Independence Day, The Sound of Music and Die Hard. Some non-Five Star but equally great editions are Fight Club and Moulin Rouge.

    Universal: Their Ultimate Editions have come under quite a bit of critisism around here in their choice of re-issues and the general lack of new extras. Some of the more impressive Collector's Editions include The Thing,Jaws and the upcoming Legend Ultimate Edition.

    New Line Cinema: Their new InfiniFilm line is an impressive line of special editions that is focused on immersing the audience in all aspects of the film and the features are tailored on a film by film basis, but usually include commentaries and trivia tracks. Titles include Thirteen Days, Blow and Rush Hour 2.

    Dreamworks: Signature Series, which is a pretty basic special edition, usually reserved for their award-willing films, and usually has heavy director participation. These include American Beauty, Gladiator, and the upcoming A Beautiful Mind

    These are the "Series" that various studios have put out, the other studios have their own "Special Editions," but just call them that. Nonetheless, Special Editions usually include:

    Commentary: The director and/or stars guide the viewer through the film, sharing anecdotes and pointing things out to the viewer. Can be entertaining or woefully dull, depending on how interesting it is. And sometimes, the actors just tear the film to shreads, like Ben Affleck on the Armageddon: Criterion Collection commentary.

    Deleted Scenes: Scenes that were removed from the finished film. Usually for a damn good reason, too.

    Extended scenes: When the scenes were long and boring...

    Alternate Ending: Sometimes it's actually an alternate ending, like on the Joyride or Fatal Attraction DVD's. And sometimes you'll be damned if you can figure what exactly is so alternate about it.

    Behind the Scenes Featurette: Remember those little things between the movies on HBO? There you go.

    Behind the scenes Feature: Far more in depth and much more interesting too. Actually contains discussion about various aspects of the film.

    Trivia Track: Remember Pop-Up video. It's like that.

    God-Only-Knows What Else: Varies from silly games to who knows what else, all in the name of filling up the disc.

    Theatrical Trailers: Self-explainatory. Sometimes you get bonus trailers too. Yee-haw!

    And there in a nut-shell, is Special Editions 101.
     
  7. Ted Lee

    Ted Lee Lead Actor

    Joined:
    May 8, 2001
    Messages:
    8,390
    Likes Received:
    0
    Trophy Points:
    0
    Can I use bookshelf sized speakers for my HT?

    The simple answer is yes - with one caveat.

    Don't let the size of a small speaker fool you. Today's bookshelf speakers pack a lot of performance into a relatively small box. Unless being driven at very high volumes, they can accurately and faithfully reproduce sound without distortion.

    But, when you look at the drivers inside of a bookshelf speaker you'll immediately notice one thing - the size of the woofer. Clearly, it is not as big as those that are found in larger floor-standing speakers.

    Unfortunately, physics is physics. To move a large amount of air (which is necessary to create bass), you need a large driver. The woofers found in most bookshelf speakers are adequate, but they simply cannot reproduce the low frequency effects (lfe) you often find in todays movies - especially action or effects laden soundtracks.

    So, if bass is important to you, you really only have two options. The first option is to skip the small speaker and purchase a larger floor-standing model. The second option is to purchase the bookshelf speakers and supplement them with a subwoofer.

    The second option is becoming more and more popular. Almost all major speaker manufacturers offer some sort of small speaker (often called a 'satellite') combined with a subwoofer...or you can create the combination yourself.

    This works well in that the subwoofer can take the job of handling the bass, while the small satellite/bookshelf speaker handles the midrange and high frequencies.
     
  8. Ted Lee

    Ted Lee Lead Actor

    Joined:
    May 8, 2001
    Messages:
    8,390
    Likes Received:
    0
    Trophy Points:
    0
    Where am I supposed to put all these speakers?

    Speaker placement is very important and can greatly affect the sound. I'll talk about each speaker and it's optimal placement.

    Mains (left/right)
    Your main speakers should be placed so that the tweeter is at approximately the same level as your ears at the listening position. If the speaker is too high or low, you may want to experiment with angling the speaker - just be careful of the weight-balance of the speaker when doing so. Angling a speaker often makes it 'top heavy' and prone to falling off a stand.

    Center
    Ideally, the center channel should be at the same height as the tweeters from the mains. If you have a front projection screen though, place the speaker directly either above or below the screen and angle the speaker so that the tweeters point to your ear level while seated in the listening position. If you have a direct or rear-projection TV, you can place it on top of the TV or use the same approach as the front projection setup, being sure to angle up or down as needed. Many center channels include an adjustable bracket in the back to assist with angling.

    Rear - Direct Radiating
    Rear channel speakers offer the most confusion and flexibility. I cannot stress enough that experimentation is key in achieving a sound-field you are happy with!

    The idea is to provide a diffused sound-field from behind you. You don't want the rear speaker to draw your attention away from the screen, thereby distracting you from what is visually happening.

    Typically, you'll want to place the rear speakers in such a manner that the sound "bounces" off another wall. You can even have the sound bounce off the ceiling! Or, you can simply have the speakers point directly at the listening position - this will provide a more directed sound, but may work well for you.

    Again, you must experiment and find what works best for you.

    Rear - Bipole/Dipole
    These rear speakers are designed to be placed on the side-wall, typically beside or slightly behind the listening position. Again, you will need to experiment and determine what works best for you.

    Other concepts
    Toe-In: This is the practice of angling the speaker inwards (towards the listening position) instead of having them face directly forward. Toe-in typically results in a more directed sound, since the tweeter is fired directly at the listener. Some manufacturers may recommend this practice...others may not. Be sure to read the owners manual. If it's not stated, by all means, feel free to experiment. Heck...even if it is stated, experiment!

    Obstructions: In a perfect world, nothing would block a speaker's sound. Unfortunately, many living rooms have couches, coffee tables, bookshelves and other items that may cause an obstruction. This is something you'll have to figure for yourself...you may want to consider redoing the layout of your room, moving the HT to another room, etc.

    Speaker Stands: These will come in handy for elevating your speakers to the correct height. An added bonus is that they typically help improve the speakers sound - the speaker will sound "brighter" or "clearer" because the tweeter is now pointing at your head instead of your knees. The bass will sound more controlled and less boomy because the bass is not being reflected off the floor.

    Calibration: This is mentioned elsewhere, but just remember to adjust all your speakers using a calibration dvd and a sound pressure level meter.

    Additional Reading: Be sure to read Dolby's speaker placement recommendations by clicking on the following link:

    http://www.dolby.com/consumer/home_e...oomlayout.html
     
  9. Jagan Seshadri

    Jagan Seshadri Supporting Actor

    Joined:
    Nov 5, 2001
    Messages:
    528
    Likes Received:
    0
    Trophy Points:
    0
    DVD-Audio and Super Audio CD: Next-generation digital audio

    Digital Audio: Then and Now
    When people think of digital audio they think "Compact Disc". Though the CD revolutionized consumer audio by being compact, durable, and great-sounding, it was implemented in the early 1980s and designers have learned a lot more about digital audio since then. Nipping at the heels of the CD are two new audio formats: SACD and DVD-A.

    What could be better than CD?
    For most people, the biggest difference between CD and the new DVD-A and SACD formats is that the new formats are capable of multichannel sound. CD has two channels (stereo: left and right) whereas the new formats can playback up to six channels to completely envelope the listener with sound.

    And you thought that CDs were great!
    When Compact Discs came onto the market, they were marketed as having "perfect sound forever". While CDs certainly sounded better than audio cassettes and dusty, worn-out LPs, CDs were great, but not perfect. Quite simply, the numbers (i.e. bits per sample and sampling rate) were not high enough to precisely capture all of the sound from studio master tapes.

    Performance Descriptions of CD/DVD-A/SACD
    Digital audio is recorded by taking 'snapshots' of sound waves. Since sound waves constantly vary in volume, each snapshot measures the volume at a specific point in time. Furthermore, each of these volume measurements is measured with a certain precision (like measuring a distance to the nearest inch). When a digital recording is played back, these volumes are played back snapshot-by-snapshot so quickly that it sounds continuous (much like watching a movie looks continuous rather than a bunch of individual snapshots).

    Compact Discs record each channel of sound by taking 44100 samples each second, and measuring each sample "from the ground-up" using 16-bits (like being able to measure up to a mile within an accuracy of an inch). This is called 16/44.1 PCM (Pulse Code Modulation). In other words, the CD *at best* can accurately record sounds from 0 to 22.05kHz with about 96 decibels of difference between the faintest and loudest sounds (i.e. dynamic range). That's pretty impressive, but if the sound you're recording exceeds those numbers, you get ugly distortions upon playback.

    DVD-Audio is similar to CD in the way it is recorded, except that its numbers are better. Each channel of sound can take up to 192000 samples each second, and measure each sample "from the ground up" using 24-bits (like being able to measure up to a mile within four thousandths of an inch!). This is called 24/192 PCM. In other words, DVD-Audio *at best* can accurately record sounds from 0 to 96kHz with about 144 decibels (theoretically) between the faintest and loudest sounds (i.e. dynamic range). It's actually overkill, but we are basically assured that the sound from a studio master tape will be accurately recorded without distortion. With numbers like these, recordings can sound more like live music and less like recordings.

    Super Audio CD (developed by the makers of the original CD: Sony and Philips) is the other high-resolution digital audio format available. Each channel of sound is recorded by taking millions of samples every second (2822400 samples per second, to be exact) BUT the samples are not measured "from the ground up". Instead, each sample is measured relative to the previous sample, and is measured using 1-bit. Playback is done by recreating the ups and downs of the recorded waveform: If the sample is '1' then increase the volume, if the sample is '0' then decrease the volume. Silence is achieved by playing back '1 0 1 0 1 0 1 0...' etc. This method is called DSD (Direct Stream Digital) by Sony, and it related to pulse density modulation. SACD is said to have a dynamic range of over 120 decibels (although this figure would be highest for low frequencies and lowest for high frequencies, instead of being a fixed value as in PCM), and a frequency range between 0 and 100kHz.

    Oh no, another format war?
    Just like the oft-mentioned VHS/Beta format war, SACD and DVD-A are vying for the same spot in your sound system, but you might not have to choose between one or the other. It helps that all of these digital audio formats are on a CD-shaped disc. Just as DVD video players can playback CD audio, it is possible that "universal" players will emerge that can play CD/DVD-Audio/SACD as well as DVD-video.

    Which should I choose? DVD-A or SACD?
    This choice is actually not a matter of who's technology is superior - both systems are outstanding and both marketing campaigns have stretched the truth a bit (i.e. DVD-Audio for stating 144dB of dynamic range when electronic noise limits you to around 130dB, and SACD for stating that its recording rechnology is superior to PCM when they often use PCM for mixing, mastering, and editing). Instead, buy the technology for the music. Sony controls a lot of entertainment media companies, so some artists will only be released on SACD. DVD-Audio has a number of record companies on-board with it, such as Warner Music, and those artists would be issued on DVD-A.

    Technically, SACDs cannot be played on conventional CD players unless it is a hybrid dual-layer disc (one layer for SACD and one layer for regular CD). DVD-Audio discs cannot be played on conventional CD players at all, but can be played on DVD-players with DVD-A capability. If the DVD player does not have DVD-A playback capability, you often can still play DVD-A discs but you'll hear a lossy-compression version of the recording (Dolby Digital or DTS).

    DVD-A and SACD outputs (or, "Once Upon a Copyright")
    These high-resolution digital audio formats were conceived partly to migrate masses of consumers to 'digitally secure' media, and to eventually stop producing the easily ripped and copied CD (and thus slow the MP3 piracy phenomenon). With this mindset, DVD-A and SACD players are equipped with analog outputs to pass along the high-quality sound to your sound system, but to prevent perfect digital copies from being made. Although DVD-A players still output a digital stream as well, it is intentionally downgraded for copyright protection reasons. These moves result in the user having to string six analog cables from their player to their receiver (or preamp/processor) to get the best-quality sound.

    Another copyright protection mechanism that DVD-A used is called watermarking, where a special authenticity code is embedded in the digital recording. While it is said to be inaudible (which is indeed possible), some people suspect it is in fact audible, and therefore inferior to SACD. SACD's authenticity code is done using a manufacturing technique involving Pit Signal Processing (PSP) which does not alter the audio data at all.

    Should I buy it now?
    As of the time of writing (April 2002), neither format has very many recordings to be enjoyed. Of the recordings that have been released, DVD-Audio tends to issue more classic-rock and modern-rock albums (from the 1970s to today) whereas SACD tends to issue more classical music and jazz. Those who favor SACD tend to say that it sounds more natural, which may actually be due to better-sounding source tapes. DVD-Audio should be capable of equaling or SACD performance, and those who engineer 5.1 channel surround recordings will soon provide better mixes for both formats.

    The fact that 24/96 PCM recordings (i.e. Digital Audio Disc (DAD) recordings...basically a regular DVD with less video and more sound) sound remarkable, bodes well for the future of DVD-Audio. However, everyone can win if more universal players are manufactured. Hopefully by 2003 or 2004 the outlook for these formats will be more clear.

    -JNS
     
  10. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    A Quick Overview of Home Theater Calibration

    INTRODUCTION

    Fellow moderator Jay Mitchosky outlined above that true home theater enjoyment is often the result of system calibration and accuracy. To that end, there are several test DVDs on the market, designed with patterns to help you dial your HT system. In the dozen discs available, there are two which are widely accepted as the most useful: Avia and Video Essentials.

    Avia was designed by Guy Kuo & Ovation software. You'll find many posts from Guy here on the HTF, he's a regular poster and usually pretty helpful when it comes to Avia related issues.

    Video Essentials was designed by Joe Kane, who is also a member here at the HTF. Joe also founded the well respected imaging-science foundation (ISF), and Video Essentials has been the calibration tool of choice since the days of laserdisc. VE has recently been discontinued, and Joe is set to release Digital Video Essentials sometime in late 2002 / early 2003.


    BASIC AUDIO CALIBRATION STEPS

    - Acquire a calibration disc (like those mentioned above) and a SPL meter like the Radio Shack SPL meter.
    [​IMG]

    - Inside your receiver menus somewhere, there should be speaker level adjustments for each of the speaker channels (consult your manual if necessary). Set each of the individual speaker settings to 0. Go into the menu- and adjust all the available speaker settings so they aren't boosting or cutting. Set them all at 0. It also might be a good idea to turn off all Treble/Bass boosts or cutting.

    - Set your meter to "slow" response, and the weighting to the setting suggested by the tones you're using (both VE and AVIA offer onscreen instructions on proper meter settings).

    - Setup your meter at your main listening position, appoximately at the height of your nose while seated, and point it forward, angled upward at about 40 degrees (a decent rule of thumb is aiming it at the point where the ceiling meets the front wall). It is very helpful to place the meter on a camera tripod- the RS SPL meter has a nice tripod mount on the back- this will help make sure you keep it in one spot.

    - Insert you test tone disc and begin the audio test for speaker calibration. Both Avia and VE have these tests, and they should be resonably easy to find.

    - The majority of discs start with the left speaker tone. While the left speaker tone is playing- increase the master volume position until you reach a reading of 75db on your meter (or 85 is you're using Avia- double check the instructions for your particular disc to determine target level. The 75db number is specific to certain tones, while others a designed to be calibrated to 85db... this will depend on which disc you're using to calibrate.).

    - There is sometimes confusion on how the meter dial/VU needle display operates. It is pretty simple: you set the dial on a number (say for example 70). Now the needle VU meter is displaying SPL relative to 70-- so when the needle hits the middle "0" position, that means the SPL of the thing you're measuring is 70db of spl. If it reads -4, that means it is 4 under 70, or 66db. Similarly if the dial is set to 80, the needle VU meter is displaying SPL relative to 80- so 0 on the meter means 80db of spl. If the dial is set to 90, the needle is relative to 90, and so on.

    So, to measure 75db spl output, set the dial on the meter to 70, and then adjust the speaker volume until the little needle hits +5 position on the meter display.

    So, to measure 85db spl output, set the dial on the meter to 80, and then adjust the speaker volume until the little needle hits +5 position on the meter display.

    - Note that it doesn't matter at what position your master volume knob is placed, or for that matter what number it says. Calibration is a measure of OUTPUT, so even if the volume knob was marked with Japanese characters- you should still be able to calibrate with no problem. Some people choose to set their master volume to a 00 position and adjust the levels from that point-- which is fine but not at all necessary. (If you chose to do this- simply set the master volume at 00, and then play the tones, using the speaker controls to get the desired meter reading.)

    - As the tone cycles to the other speakers- leave the master volume alone- and adjust the individual speaker levels in the receiver menu so that each speaker measures the same level on the meter. It may take a couple times through to get it right- but keep working at it, and leave the meter in the same place.

    - At the end, take note of where your master volume knob is (what number)- this is Dolby's Ref level. You probably won't listen much at that position-- but often it is helpful to know how many clicks below ref you are.


    WHAT THE HECK IS REF LEVEL ANYWAY?

    In a nutshell, Dolby specifies an ideal playback level for their theatrical soundtracks and for the mixing envirinments in which those soundtracks are created. So, unlike music, movies are technically created with a standard playback level in mind. Based upon this intended level, dialog and effects are mixed at very specific levels to offer similar sound levels across various dolby soundtracks.

    This playback level is basically defined as 105db peak level from any single speaker in the dolby playback system. By using tones on VE or Avia- they are specifically defined to give you this playback level.

    Since VE's test tones are exactly 30 steps below the maximum level - calibrating that tone to 75db of SPL in your room means you have calibrated your system to playback 105db when given a peak signal.

    Similarly, since Avia's test tones are exactly 20 steps below the maximum level - calibrating that tone to 85db of SPL in your room means you have calibrated your system to playback 105db when given a peak signal.

    So, if you calibrate using those tones, and their intended target level (75db for VE or 85db for Avia)- that position on your volume knob will be dolby's ref level, providing you with a system that is now calibrated to offer 105db peak output.

    Most home users don't listen at dolby's specified levels- but often it is a good point of ref when seeking help or advice on forums such as this one.

    -Vince
     
  11. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    Trophy Points:
    0
    Choosing the right Speaker Wire

    Choosing the right speaker wire can depend on power/length, budget, and priority. Spending less than $1 per foot on 12 gauge wire is what most people do since it's cheap, and gets the job done well. The wire may not last forever but it does perform very similar to higher costing speaker wire. Companies that do sell wire exceeding the cost of the norm, often simply advertise that theirs sounds better.

    Monster states their speaker wire contains a:
     
  12. chella

    chella Stunt Coordinator

    Joined:
    Apr 16, 2002
    Messages:
    66
    Likes Received:
    0
    Trophy Points:
    0
    Different Video and Audio connection cables and types

    VIDEO CONNECTIONS
    [​IMG] Component Video: The signal is split into three parts, luminance information (Y), two channels of color (Pr & Pb) - terminated by three RCA connections (or once in a while with a locking connector called BNC). Component is the best possible connection for many devices. DVDs store video information in the component form - and so connecting your DVD player to the TV using a component video cable offers the path of least transformation and results in the best quality.[​IMG] S-Video: In S-Video, the signal is split two ways - luminance (Y) and color (C) - terminated by a single terminal that looks similar to a computer keyboard/mouse PS2 terminal. Provides a high quality connection.[​IMG] Composite Video: The composite video signal combines all information into a single signal path - terminated by a single RCA jack. Usually considered one of the lowest quality video connections.

    More on Quality: On a normal direct view TV one may not see much difference in quality between S-Video and component video. But on large screen, RPTV and HDTV the difference will be obvious. If your TV is large RPTV or a HDTV, then you would want to connect using component video cables. If your TV is relatively small (less than 36") direct view TV, S-Video may provide the optimum quality


    AUDIO CONNECTIONS
    [​IMG] Analog - RCA: Most commonly used analog interconnect. Normally available as pairs of cables - Left (white) and Right (red) to connect stereo equipments. Mostly 50-Ohm cables. This is also used to connect the sub-woofer at a line level. The sub-woofer cables can be of a specialty cable - they do not connect the equipments electrically; in this case the cable will also be directional.

    [​IMG] Digital Coaxial /Digital RCA: Digital interconnects used to connect digital equipments such as DVD players. Uses the similar terminal as the analog RCA cables, but the impedance must be at least 75 Ohm.

    [​IMG] Digital Optical / Toslink: Common optical link between digital components such as DVD, CD and MD players. Made of glass fibers, much thinner than the digital coaxial cables. Has a square plastic connector that often has cover / plug to protect the terminator when not used.

    [​IMG] Balanced / XLR: A fairly large 3-pin locking terminal, used in high-end audio equipments. Commonly seen in microphones power amplifiers to carry balanced line level analog audio signals. Rarely found with different number of pins (2 to 7).

    [​IMG]DB-25: Mostly used in the computer world as the SCSI interface, sometimes used in high-end audio equipments to carry multi-channel signal.




    OTHER AUDIO/VIDEO CONNECTIONS
    [​IMG] VGA/SVGA: A 15 pin D connector most commonly used to connect monitors to computers. Sometimes used in Digital TVs and projectors. Usually carries video signal on 5 lines (Red, Green, Blue, Horiz Sync, Vert Sync)- and can often outperform component connections.

    [​IMG] BNC: Bayonet style locking connector – used in high-end video equipments and some high definition tuner/receiver.

    [​IMG] F-Type: This is 75-Ohm coaxial cable is most commonly used to connect cable TV feed to your system. Available in both threaded and non-threaded form.

    [​IMG] SCART/Peritel: – A multi pin connector commonly used in European countries to carry both audio/video signals. The same cable/terminal can be used to carry different type of video (RGB, S-Video and Composite) and analog stereo audio signals.



    For another look at these various connectors and connector types, you can check out our friend Chris White's excellent connector glossary here:
    http://white.hometheatertalk.com/connectorglossary.htm

    images added by V. Maskeeper 11/19/02
     
  13. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    If I buy a 16x9 wide screen TV, will I get rid of the black bars forever?

    Nope.

    You're wrong for assuming that a 16x9 set will completely eliminate the bars. The shape of your TV is 16x9. If you attempt to play any material that isn't 16x9 (either wider or narrower), without stretching or cutting off parts, there will have to be unused area (black bars).

    A 16x9 set will perfectly contain some widescreen filmsand you will see them without bars. However, films with an aspect ratio of 2.35:1 (like Gladiator, Armageddon, T2, Harry Potter, etc) are wider than the 1.78:1 (16x9) TV frame. In order to present the film in the proper shape without cropping, a small amount of unused space will exist above/below the picture area.

    You will have bars any time the content differs in size from the shape of your screen.

    For example, to properly display 4:3 TV programming- there would be black bars to the right and left, this is just unused space because the program shape is different than your TV's shape. Some TVs offer a stretch mode which unnaturally elongates the 4:3 picture to the width of your set-- however without stretching it, the picture would be less wide than your set (resulting in unused picture on the sides).

    The same is true for Movies with a 2.35:1 aspect ratio. These films are wider than your 16x9 set, so you will still need small bars of unused space at the top and bottom in order to properly present the width of the material.

    So, the basic answer is: If the content is wider than your set (2.35:1 aspect films) you will have small bars at the top and bottom-- if it is narrower (like 4:3 normal TV programming)- you will have bars on the sides.

    So, buying a 16x9 set doesn't eliminate black bars- it simply gives you a wider aspect set. If you watch only 16x9 (1.78:1) aspect material, you'd never see bars-- but since many films are wider, and most TV is narrower- you'll never completely eliminate them.

    So, it's best to watch the program, not the bars.


    Here's some posts where this topic has been asked in the past:
    http://www.hometheaterforum.com/htfo...threadid=76566
    http://www.hometheaterforum.com/htfo...threadid=69492
    http://www.hometheaterforum.com/htfo...threadid=69310
    http://www.hometheaterforum.com/htfo...threadid=59882
    http://www.hometheaterforum.com/htfo...threadid=69229
    http://www.hometheaterforum.com/htfo...threadid=47685
    http://www.hometheaterforum.com/htfo...threadid=76820
    http://www.hometheaterforum.com/htfo...threadid=67391
    http://www.hometheaterforum.com/htfo...threadid=79129
    http://www.hometheaterforum.com/htfo...threadid=38567
    http://www.hometheaterforum.com/htfo...threadid=18857
    http://www.hometheaterforum.com/htfo...hreadid=105346
    http://www.thedigitalbits.com/articl...hic/index.html
    http://www.thedigitalbits.com/articl...ic235demo.html
     
  14. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    What is the difference between MATRIXED and DISCRETE audio channels?


    Discrete means that you have a mulitchannel soundtrack that is stored so that each of the tracks stays isolated from each of the other tracks, and you have true seperation between all the channels.

    Matrixed means that the multichannels are blended together and stored not isolated from one another. In this case, instead of having each track available as a discrete audio stem- you have to pass the audio through a processor in order to turn it back into multichannel.

    Think of it this way:

    Imagine you have 6 different colors of water you wanted to pipe from the water plant to your house. When they get to your house- they need to be separate and placed in special tanks, one for each color.

    In a discrete system- each color would be routed from the plant to your house in individual pipes. The water would start out as 6 individual colors, would travel completely separate from one another - each on a dedicated pipe, and would arrive at your home on these 6 discrete pipes. You could then route each color to the appropriate tank, and have the pure 6 colors of water you started with at the plant.

    In a matrixed system- the 6 colors water would be combined together and would travel in maybe only two pipes. They would be mixed together in a specific way at the plant- then they would travel down the pipes to your home, where a filter would try to sort them back out into the 6 original colors.

    So, in the case of a matrixed system like Pro Logic- this takes 4 original stems of audio and blends them together into just 2 channels ("pipes"). At the other end, a pro logic processor (a filter)- tries to sort them back out into the 4 original stems they started with.

    In the case of DD EX, which is a 6.1 channel system that has a matrixed rear center channel- it takes the rear 3 channel audio stems (Rear Left, Rear Right and Rear Center) and blends them together into the 2 available rear channel "pipes" (The front channels and the sub remain completely discrete) - and a EX processor can then sort them back out into the 3 original stems.

    Dolby Digital EX basically takes 7 colors or water and passes them using only 6 pipes... using a filter at the other end to re-create that 7th color.


    Which formats are which? What is DTS-ES? Is there a DD EX 6.1 discrete? How big of a difference does it make?


    Dolby digital does not offer a discrete 6.1 format at this time. Their 5.1 system is a completely discrete audio format, and they simply added a 3rd rear channel (a rear center) using a matrix system as described above.

    DTS offers BOTH a "discrete" 6.1 version called DTS-ES Discrete and a matrixed 6.1 version, which I believe they call just DTS-ES.

    How big of a difference does it make? Well, to me, very little.

    Although I personally saw Dolby's decision to make the rear center a "matrixed" channel as a step BACKWARDS- to be honest this type of matrixing is the easiest to do. Any time you have a stereo signal- it is very easy to find a "center" image within that signal. Simply analyze the stereo signal, and figure out what is being sent equally to both speakers- and boom, you have a "center" channel. For the most part, I would say that the difference between a matrixed 6.1 signal and a discrete 6.1 signal would be slight-- especially for rear channels.

    Also, keep in mind that there are less than 20 discrete DTS-ES encoded titles on the market right now (I'd even guess less than a dozen, but don't quote me on that).

    Having all decoding schemes available in your receiver is probably the ideal, just to make sure you can enjoy everything that is available- but if your processor doesn't do DTS-ES discrete 6.1, I wouldn't sweat it too much.

    Also- another issue you might need to understand is the idea of the EX matrix type decoding. As I said above, in real basic terms a EX processor takes the 2 rear channels and analyzes the two signals, and figure out what is being sent equally to both speakers- and creates a "center" channel from that.

    This process can be activated with or without specific EX encoding.

    In other words, you could run EX processing on any 5.1 title, and chances are you'd get some sort of rear center channel activity. On many titles, it is equally good as any title specifically created for EX.


    The truth is, as far as I can tell, dolby has no intention of redoing their system to create a discrete 6.1 system. Without getting too technical- the basic design of dolby digital audio encoding means that a discrete 6.1 system probably couldn't be backwards compatible to a 5.1 decoder, and new docoder systems would need to be designed.

    So a theoretic Dolby Discrete 6.1 disc probably couldn't be played back on a current system- where DTS discrete titles are backward compatible and work with the regualar DTS decoder.

    Since dolby seems to have no desire to do anything beyond the matrixed DD-EX 6.1, and the fact that Dolby is releasing 10 times as many 6.1 titles as DTS, it seems obvious that DD-EX will be here for a while.
     
  15. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    I got a great offer to buy Speakers from some installer who had leftovers from a job (or some guys who had some extras the boss didn't know about). They came up to me in a white van, and offered really great brands like DOGG DIGITAL. Are these a good deal?

    NO!

    Run away! These are widely known as "White Van Speakers" because they are sold by guys in white vans on roadsides all over the US (and the World).

    I honestly think that if you haven't been approached by the white van speaker people (or know someone who has)- then you are in the minority. I have seen stories of this from as far away as Australia.

    See also:
    http://www.hometheaterforum.com/htfo...threadid=91046
    http://www.hometheaterforum.com/htfo...threadid=85580
    http://www.hometheaterforum.com/htfo...threadid=84535
    http://www.hometheaterforum.com/htfo...threadid=80581
    http://www.hometheaterforum.com/htfo...threadid=75504
    http://www.hometheaterforum.com/htfo...threadid=74718
    http://www.hometheaterforum.com/htfo...threadid=68133
    http://www.hometheaterforum.com/htfo...threadid=60753
    http://www.hometheaterforum.com/htfo...threadid=15451
    http://www.hometheaterforum.com/htfo...threadid=15391
    http://www.hometheaterforum.com/htfo...threadid=27237
    http://www.hometheaterforum.com/htfo...threadid=41012
    http://www.hometheaterforum.com/htfo...threadid=39478
    http://www.hometheaterforum.com/htfo...threadid=39478
    http://www.hometheaterforum.com/htfo...threadid=97795
    http://www.scamshield.com/
    http://www.crimes-of-persuasion.com/...aker_scams.htm
    http://www.ripoffreport.com/

    Speakers Sold as:
    Acoustic
    Acoustic Monitor
    Acoustic 9901
    Audio File
    Denmark
    Digital Audio
    Dogg Audio
    Dogg Digital
    Dynalab
    Epiphany
    Omni Audio
    Paradyme
    PSD


    Note that they use "sound alike" names to popular speaker brands (Paradigm, Acoustic Research, PSB, etc).

    The WHITE VAN phenomenon is so common, The HBO skit commedy "Mr. Show" even did a spoof of the guy selling speakers out of the back of his van.

    In my town, the guys have given up on cheap speakers and now try to sell you steaks out of a cooler in the back of their truck. MMMMMMMM, cuts of beef from hairy guy in a rusted out toyota pickup- nothin' like it!
     
  16. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    HTPC: Home Theater Personal Computer
    An introduction to HTPC

    Most modern video projectors, at least the majority made since the early 90's, are designed to take higher resolution images from computers (1024x768 for example). The modern projector was designed to do computer presentations, so using them as strictly video projectors means a lot of usable resolution going to waste!

    Many of the new digital projectors have built in scaler devices that process incoming low-resolution video signals and "scales" them up to the resolution that the projector wants them to be (called the projector's "native resolution"). However, many of these internal scaling devices are poor and introduce artifacts to the picture in the process of resampling the image... An outboard scaling device would be able to do a better job and create an image equal to the "native resolution" of the projector- but a good scaler costs thousands of dollars!

    Someone somewhere got the bright idea that the mpeg decoding engine on a high buck PC video card coupled with a DVD-Rom drive might make a good dvd player to feed high resolution images to these compatible devices. By connecting a PC to the projector via the VGA connection you could scale the DVD playback to really high computer resolutions- exploiting the potential of these projector devices and avoiding the poor processing of internal scalers...

    Turned out, they were right! The scaling possibilities of a computer coupled with high buck super-dooper video cards became serious competition for $10,000 video processors, all for less than $1500! This is the best way (in terms of value) to get to quality DVD images, if you have a projector or set that supports VGA or better resolutions...

    The image is really good, much smoother and more film like than even a progressive scan DVD player can offer. The scaled output from decent HTPC even rivals majority of expensive scalers, up to and including systems costing $10,000+.

    So, once it was started the quest began- the computer geekers and tweakers came out of the woodwork. Guys who were good with computers anyway saw the potential- and many specific applications have been written making computers the ideal player for DVD and so much more. There are applications (like Powerstrip) that let you dial in resolution to the pixel- meaning you can find the best possible "sweet spot" resolution for your projector or display device.

    The HTPC craze has extended beyond the Front Projector users- now that rear projection HDTVs are becoming popular- many support higher resolution inputs, just like Front Projectors can, so a PC can be used to scale DVD to HD resolutions like 720p, 540p or 1080i to a HD compatible display! Some rear projection sets will even handle computer resolutions like 1024x768 and higher... Many RPTVs have a DB15 VGA style input or DVI- but even if not several manufacturers make a transcoder that will take computer input and output HD Component (expect to spend $300ish).

    If you're interested in learning more about HTPC, you can read the HTPC/PC area here on the HTF: Home Theater Forum HTPC Area

    Or the great (but very advanced) HTPC area on AVS: AV Sciences Forum HTPC Area

    In addition to the appeal of excellent DVD playback, the HTPC concept has hundreds of possibilities like:
    -CD and mp3 playback in your HT, with visualizations and file controls.
    -PVR functionality- basically a custom TIVO like machine that with the right configuration can record HD programming as well!
    -PC tasks like Websurfing and gaming in your HT on the big screen!
    -You can use it to scale external sources (with the excellent, free Dscaler).
    -Completely custom resolutions for Projector/HDTV owners: dial the sweet spot of your set
    -Region free playback, PAL conversion, no layer changes.
    -Custom “preroll” and intros for movie night. Compile your own theater intro- and even play it back at full HIDEF resolutions direct from the PC (no need to down convert it like DVD-R users do!)
    -Neat add-on applications like DVD subber allow you to access subtitle streams from the internet (useful for anime fans or other foreign films not subtitled for English!)
    -DVD playback applications that allow you total control: have your movies play as soon as you put them in with your preferred soundtrack and settings (skip the warnings and the menus), automatic aspect ratio adjustments and more.
    -See what others are doing with their HTPC here: http://www.avsforum.com/avs-vb/showt...threadid=31877


    I’ve got a video card with a Svideo output on it, can I use this for HTPC?

    Yes, although you miss a good deal of the point of HTPC, in my honest opinion.

    If you're coming from the PC via SVIDEO, you are getting a signal that has been down converted to standard interlaced NTSC resolution not matter how high your desktop resolution is set. The desktop setting is the VGA output resolution; as long as you're using Svideo you're nowhere close to that.

    The only way to get the actual full resolution from the PC to a TV set would be to use the RGB (VGA 15 pin connector) output or DVI output from the card.

    The bottom line is that the TV (S-video) output on these cards provides a video feed compatible with a standard TV- that is 480i- regardless of your desktop settings.

    Even if you’re looking to just pass regular DVD playback to a standard TV, the majority of these cards have a $2 circuit to handle this TV send- so most are lower quality than even an entry-level DVD player. So if you’re going Svideo, chances are good even a $200 DVD player would be better for you than the HTPC solution.


    How can I get the HTPC to hook up to other sources besides DVD?

    You need some sort of video input card to accept the incoming video signal and display software to put it on screen..

    Most people use an excellent free application called Dscaler. This is an open source PC based scaling engine that does amazing video processing. It does full scaling to output resolutions, does 3:2 pulldown, aspect toggling and even has built in TV tuner functions. It is free: http://dscaler.org

    The one hitch with Dscaler is that you have to use a particular type of input card: any card based on the Brooktree (now Conexant) chipset. DO NOT PLAN TO USE THE ATI INPUT ON THE ALL IN WONDER CARDS FOR INPUTTING VIDEO TO DSCALER. These video inputs are mediocre at best, and will not work with Dscaler. You can check the Dscaler FAQ for some specific cards, or just do a search on the AVSforum and start reading. I got an I/O Magic input card from Circuit City for like $35- it's a little blown out on the whites- but for analog cable and a few Dreamcast games, it's "good enough". Another hitch is that your OUPUT video card must be AGP, it won't work with a PCI card (it will but you run a serious bandwidth risk to doing decent resolutions).

    If you're looking for top of the line input, a member on AVS (look for username KBK) does a modification of the WinTV series card that is supposed to provide the very best quality external input. Expect to spend a few hundred bucks to get one however!

    One extra note on the “cutting edge”: Some people have started using SDI input Conexant cards with Dscaler, and have gotten their DVD player or DSS receiver modified to put out a SDI digital output. This is really the cutting edge as far as top quality processing goes- and it won't help you for analog sources like VHS and is not yet available for any video game systems, but for DSS and DVD provides Dscaler processing (which is great) with a direct digital path!

    Also, you can read the FAQ over at http://www.dscaler.org/ which has plenty of details on how the software works, what cards to look for, etc.

    If you'd like to go beyond what Dscaler and these Conexant cards can offer, some other popular solutions include pro input cards (like the Falcon) and a new card (Holo3DGraph) which represent the most recent top of the line. The Holo3DGraph also includes Faroudja HW deinterlacing, SDI, & component video input.


    Ok, I’m sold- can I buy a HTPC somewhere or do I have to built one?

    Several companies are now offering what’s called “TURN KEY” HTPC configurations- AVS and Digital Connection both offer several excellent models of HTPC. However- it is far more cost effective to build one yourself if you are even remotely computer literate (or even if you’re just brave!)

    Like with any portion of PC use, what is a “hot” technology changes seemingly everyday, but the basics for HTPC are:

    Video- ATI Radeon based cards are the popular ones for HTPC output as they usually exceed similarly priced cards in MPEG decoding.

    Audio- M-audio (aka “Midiman”) cards are very popular in HTPC circles for offering “bit for bit” digital transfer. Some people use Soundblaster cards however.

    Software- TheaterTek is very popular for HTPC, with the free ZOOM player also being a top choice!

    As far as the rest of the hardware- I’d point you to these FAQ documents on the AVS forum. Happy hunting!:
    http://www.avsforum.com/avs-vb/showt...22&perpage=999
    http://www.avsforum.com/avs-vb/showt...14&perpage=999
    http://www.avsforum.com/avs-vb/showt...00&perpage=999
    http://www.avsforum.com/avs-vb/showt...37&perpage=999
    http://www.avsforum.com/avs-vb/showt...24&perpage=999
    http://www.avsforum.com/avs-vb/showt...07&perpage=999
     
  17. Greg_R

    Greg_R Screenwriter

    Joined:
    Apr 9, 2000
    Messages:
    1,996
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Portland, OR
    Real Name:
    Greg
    This post is meant to discuss PVR hardware and services. There are frequent changes to available hardware and recording software so it's important to do your own research after reading this document. Having said that, here's info on PVRs....

    What is PVR?

    PVR stands for Personal Video Recorder.

    A PVR is a device that allows you to record content onto a hard drive and play it back at a later time. These devices sit between your source (cable tv, dish, satellite, etc.) and your TV. Well known PVRs include TiVo, ReplayTV, DishPVR, & UltimateTV.

    In addition to recording programs to watch later (known as "time shifting"), PVRs also feature advanced menus of program material which allows you more options in what you'd like to record (for example you can tell it to record all Clint Eastwood Westerns or every first run episode of a favorite TV program). Depending on the unit, you are also able to watch things it recorded previously or watch TV while other channels are being recorded. A PVR also has the ability to skip commercials in prerecorded material with a single button, and some PVR units buffer the live TV feed to the hard drive giving you the ability to "pause live TV" or even rewind during a live broadcast. The show will continue to record but you can jump to any spot in the recording, watch the segment, and then jump back.

    In order to access the more advanced PVR features, a membership fee is usually required (sometimes DirectTiVo service include the PVR functionality in the package price). Most companies offer a lifetime membership in addition to monthly membership fees.

    A PVR dramatically changes the way you watch TV. Personally, I have all the shows I like to watch set up for recording. When I feel like watching TV, I go to my recordings and watch the program of my choice (fast forwarding through commercials of course). Having a PVR unit means that any time you sit down to watch TV, there is always something good available for you to watch!

    How do PVRs compare with VCRs?

    VCR records onto a tape which can be removed and stored and can only store a few hours of content. A PVR records onto a hard drive which, depending on the model, can store 100s of hours of programming.

    A VCR requires no membership fees, PVRs have monthly charges (or lifetime memberships).

    To record on a VCR, you must know where and when a program occurs (or the VCRplus code). With a PVR, you are able to browse all upcoming features (by title, genre, time, actor/actress, etc.) for the next few weeks and select the programs you wish to record. A PVR also has the ability to record all instances of a particular show or it can be limited to first runs.

    Additionally, a PVR can guess what you might like to watch (based on your viewing habits) and record that show (this feature can be turned off).

    A PVR is able to record while playing back a previously recorded program- a VCR cannot do this.

    A PVR as part of a satelite system like DirecTiVo (described below) and Dish PVR can also record premium soundtracks like Dolby Digital. VCR's can only record the 2 channel soundtrack.

    PVRs also allow you to time delay programming (see above for description). The video quality of a PVR can also be better than a VCR, depending on the encoding options selected.

    Finally, when recording you have the option of 'padding' the program by a few minutes (start early and finish late) in case the network is lax in their start/stop times.

    Which PVR should I buy / what is available?

    There are many choices in terms of models and brands but there are four main services: TiVo, ReplayTV, DishPVR, & Microsoft's UltimateTV. Each service differs with respect to program selection, cost, & connectivity. There is also the free option using a computer which will be described below. You should read the links in the 'more PVR info' section before making a purchase decision. Below, I'll highlight the major differences (I've ignored discontinued models).

    TiVo: Cost is $13/mo or $250 lifetime. TiVo does not have a web browser or other internet applications. The video connection is S-video, composite, or RF and units do not come with a digital audio connection. Standard connection for TiVo program guide updates is a built-in dial up modem. TiVo takes an incoming video stream and encodes it via MPEG onto the hard drive. The largest TiVo can hold up to 80 hours of program content. TiVo also automatically buffers the current program for up to 30 minutes (i.e. past 30 minutes are always available).

    There are also DirecTiVo units which combine a DirecTV receiver (dish) with a TiVo. These units can only record DirecTV, have two tuners and a digital audio connection and are further described in the section entitled "How is DirecTiVo different than a regular TiVo?".

    ReplayTV: Cost is $10/mo or $250 lifetime. ReplayTV has the same connections as a TiVo but also includes a VGA video output (the 5000 series has progressive output), a digital audio connection, and an Ethernet jack. ReplayTV allows you to set up recordings over the web and each model can share data with similar models on the same LAN (i.e. all 4500 series can see each other and play shows recorded on the other box). ReplayTV will sort your recorded shows by category and buffers as many minutes of the currently viewed program that you want (up to space constraints). Maximum storage for the largest unit is 320 hours. Finally, ReplayTV has the ability to skip commercials (different than fast forwarding through them). Although it has a digital audio output, it will not record digital audio (i.e. DD 5.1) and will only output PCM streams.

    DishPVR: Cost depends on the programming package you choose. The basic DishPVR is a 30 hour recorder with SVideo and Toslink outputs. The more advanced unit is a 90 hour recorder with dual-tuners and picture-in-picture features. Basic features like pausing, rewinding, and fast-forwarding programming are all included.

    UltimateTV: Cost is $10/mo and includes 3 hours of internet access. For an additional $20/mo you can get unlimited internet access (or use your ISP for $5/mo). UltimateTV is a Microsoft product and integrates WebTV with a PVR and DirecTV unit. The unit will only work with DirecTV as a source (like DirecTiVo). Video output is S-video, composite, or RF. Audio output is digital audio (Toslink) or analog RCAs. The unit also includes printer and USB ports for additional functionality. The largest unit can store up to 70 hours of content. Internet connectivity is via phone jack. Unfortunately new UltimateTV units are not available (but the service is). However, there are rumors of a version 2 UltimateTV so I'm including it in the FAQ.

    Build it yourself (HTPC): With a huge hard drive array and a capture card, you are able to record video streams using your home computer. There are web sites that contain program data which allow you to set up a recording on your capture card / tuner. The amount of recording is only limited by the available disc space. Additionally, you are able to record any type of content (including HD if you have a HD tuner card). Time delay and other features are available but functionality is not as smooth as a set top box, but the options and solutions are growing everyday. Both HTF and AVS forum have HTPC areas... AVS's is very active and has a lot of FAQs and help for you to get started. Strong knowledge of computers is highly recommended!

    How is DirecTiVo different than a regular TiVo?

    A DirecTiVo does NOT include a MPEG encoder (since DirecTV is already broadcast in that format)-- it simply captures the incoming digital stream directly from the dish feed to the internal hard drive for playback later. This means that you are NOT able to record other external video sources with a DirecTiVo (a regular TiVo will record external video sources). The DirecTiVo units also have a digital audio connection (Toslink) and will save digital audio streams (like a DD 5.1 from a HBO movie) directly from the DirecTV feed (a regular TiVo does not offer this feature).

    If you subscribe to DirecTV's premium service, the TiVo service is free. Otherwise it is $5/mo (you can no longer get a lifetime TiVo membership with DirecTiVo). If you have multiple DirecTiVo receivers, the TiVo cost does not increase (note: These fees do not include the DirecTV service itself). DirecTiVo also allows you to record 2 shows at the same time (if you have dual LNBs on the dish), even if you're watching another recorded program (a very nice feature).

    Can a PVR record HD content?

    Currently, commercial units do not record HD streams due to the large amount of drive space a recording consumes and the lack of affordable encoders that can compress the HD video stream. Using a HTPC, you are able to record HD content if you have a HD tuner card in the computer and appropriate software. The computer cannot compress the stream in real time so the raw video is recorded. This means the files takes up a very large quantity of disc space.

    What happens if I let my membership fees lapse?

    You are still able to view live TV and make manual recordings. However, advanced menu features (search, timed recording, etc.) are not available.

    My TiVo can only store 30 hours. Can I increase the capacity? Can I stream video off the unit onto my home network?

    There are many well documented ways to hack these units. Any opening of the case will void the warranty, so consider hacking an "at your own risk" endeavor. Info can be found on the TiVo forums listed below.

    Where can I go for more PVR information?

    - An excellent source for TiVo / ReplayTV / UltimateTV comparisons
    - Another detailed comparison between ReplayTV and TiVo:
    - ReplayTV FAQ
    - TiVo forums (inc FAQs)
    - AVS HTPC forum
    - A sat forum with additional areas specifically for PVR.
     
  18. Greg_R

    Greg_R Screenwriter

    Joined:
    Apr 9, 2000
    Messages:
    1,996
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Portland, OR
    Real Name:
    Greg
    Why is my subwoofer and/or speakers humming?

    There are a few possible sources of hum in your system. The sections below are an attempt to describe these issues as well as specify their solutions.

    Ground Loop:

    What is ground loop interference?
    Ground loop interference causes the vast majority of hum related complaints on HTF. This is caused by a difference in electrical potential between your cable TV or satellite cabling and your audio system. Although these long cable runs are supposed to be properly grounded, very few installers take the time to install the system properly. The cable should be grounded to the house ground, not a pipe or small ground tap outside. The result is that this ground potential causes a 60Hz hum on the audio portion of your system. This audio range is usually reproduced by a subwoofer so people blame it on their sub. The problem usually appears when the user starts using components with 3-prong AC power cords. Without any 3-prong (grounded) devices, a ground potential will not exist through the cable. Note that 'floating' an existing ground plug (by using a 3 prong to 2 prong adapter or by cutting the ground prong off) is usually not safe!

    How to determine if it's a ground loop issue:
    Unplug the cable going into your satellite or cable TV box. If the hum disappears, then you have identified your problem. Other possible culprits are radio antennas or long runs of cable (especially if they are not shielded properly). Go through the system and determine which part is causing the problem.

    Solutions:
    For a cable ground loop you will need a part that breaks the grounding path of the cable into your system. Recently Radio Shack has begun to sell ground loop isolators for RCA interconnects. A Radio Shack 75ohm->300ohm converter screwed into a 300ohm->75ohm converter will also perform this task. Radio Shack also sells FM traps and Ham radio filters that may be useful if you live near broadcast towers. Using quality coax cable will also help. I like to recommend "Quad Shield RG6 coax" which can be found at your local home improvement store. The Quad shield helps to keep the signal conductor inside the cable from picking up interference.
    [​IMG]NOTE: Using a 'cheater' plug (3-prong to 2-prong adapter) is dangerous and not recommended! Unless the manufacturer specifically recommends the use of a cheater plug (also known as a "ground lift"), do not install one in your system. If you disconnect the ground and something inside the component's case shorts out then you could become the path to ground (i.e. electrocution). While these devices will sometimes reduce ground hum- you should understand the risk involved.
    Transformer hum:
    A transformer is a device that takes one voltage level (incoming power) and transforms it into another level (power for circuitry). This is achieved though the principles of magnetism and electricity. Because of this, the transformer can literally vibrate (called 'lamination rattle') and needs to be securely fastened to the amplifier enclosure. If you hear a serious vibration/rattling sound from your amplifier then get your local technician to tighten the fasteners holding the transformer.

    Servo controlled subwoofer:
    Some subwoofers are servo controlled, meaning they use a small device to actively monitor the speaker cone's motion. The feedback of this device will result in a very soft hum (i.e. you can only hear it if your ear is close to the speaker). This is a drawback of the servo design and there is no solution (beyond getting a non-servo design). It should be mentioned that many people will accept this in order to gain the potentially increased accuracy of a servo design.

    Bad cables:
    It is possible that some cables could have a slight short due to shoddy construction or damage. Additionally, poorly shielded cables can potentially pick up EM noise (which can result in unwanted noise during playback). Note that adequate cabling is not expensive... Radio Shack Gold and AR brand cables are two examples.

    Noise on the house power circuits:
    It is possible for some devices to inject a large amount of noise into your HT system via the power wires. Examples of these noisy devices include dimmer switches and refrigerator compressors. If this is causing issues with your system, relocate either the noisy device or the system onto a different circuit. Some forum members choose to install dedicated circuits for their large HT systems. This should be done or supervised by an electrician. Another solution is to install a filtering device or regenerate the AC on the circuits going to your HT. These devices vary in cost and some include surge protection.
     
  19. Neil Joseph

    Neil Joseph Lead Actor

    Joined:
    Jan 16, 1998
    Messages:
    8,332
    Likes Received:
    1
    Trophy Points:
    0
    Real Name:
    Neil Joseph
    Front Projection
    How do I select one for my my needs?

    First things first, let me first explain what front projection is. Basically what I am talking about is using a projector to project a video image onto a screen that is in front of the viewer. This is the same method used in movie theatres today with the screen at the front of the room/theatre and the video projector located towards the back of the room.

    With the prices of front projection coming down to reasonable levels, and with HDef becoming more accepted by the masses, more and more people are finding that a front projection system is within reach and an acceptable upgrade for their home theatres. There are a lot of questions that must be answered in order to know which type of projector is best suited for your home theatre.

    First of all, there are various types of projectors. I will not discuss the differences in this article in great depth but only cover the most important issues. The major types of projector consist of CRT, LCD, DLP, DILA and LCOS projectors, with the first 3 being the most common for home use. Each has its advantages and disadvantages so these must be factored into the final decision process.

    The MAJOR advantages/disadvantages between projector types

    1- CRT - The earliest front projectors were CRT (Cathode Ray Tube). Traditionally they were expensive, heavy, and difficult to set up but delivered top notch picture quality. Many are not as bright as the digital projectors of today so they will need a room that has absolute control of ambient light to prevent the picture from being "washed out". The biggest advantage though is their ability to produce very good "blacks". These units need to be set up at one point and not moved from that point. Once set up, convergence will also have to be done for best results. Many can be found used at reasonable prices.

    2- LCD - These digital projectors have become more and more popular today as they offer a lot of flexibility and ease of use. Prices vary from cheap to around the mid-point of the range of prices. Many offer zoom lenses that allow a range in their location because the picture size can be zoomed to the size of the screen, as well as keystone correction to correct for projector height in relation to the screen. Some of the things to watch out for are possible screen door effect where the pixels structure can be seen from a few feet away, and black level being more dark grey than black. These projectors can offer colours that are "punchy" when compared to other digital projectors like DLP. This is not necessarily true for all LCD and all DLP projectors though. Other considerations are bulb life and the "dead pixel" issue. Once a bulb has reached end of life, it will need to be replaced and could cost a couple of hundred dollars to do so. Sometimes an LCD projector can have what is called a dead pixel that does not change colour like it's neighbouring pixels do. This is not very common though among the newest generation of LCD projectors. A dead pixel may hardly be visible unless you look very closely at the screen. You may observe a pixel that stays green all the time for example. The problem arises if there are a group of dead pixels together in one area which may cause it to be visible from the main viewing area. lastly, LCD projectors do not suffer from "burn-in", a problem that can occur with CRT projectors when displaying bright static images for too long.

    3- DLP - These digital projectors differ from LCD in the way they create an image but basically with DLP (Digital Light Processing), pixels are also projected at the screen. They offer many of the same features as LCD projectors with regards to flexibility and also some of the same concerns like bulb life. Screen door is less of an effect than LCD, typically, but not always. Contrast ratios can often be higher than with LCD, creating better blacks, but light output can also tend to be lower than with LCD. Often, the colours are less saturated and more washed out than with their LCD cousins. Other considerations are the "rainbow effect" that can be visible on many DLP projectors, typically those with slower colour wheels and some people have claimed getting headaches while viewing movies on some DLP units. The following is an interesting article from Texas Instruments on the concepts of DLP projectors and how a single chip revolutionized these projectors. dlp.com "DLP technology" (click "Launch our demo" under "See How It Works" on the upper right)

    4- LCOS/DILA - This is another type of digital projector. There are presently not many LCOS, aka DILA, projectors on the market for home use and they are also a lot more expensive.

    OK, so how do I select one for my my needs?
    There are various considerations to determine which type and model of projector is right for your setup. A useful search function can be found at Projector Central, that allows you to search on price, brightness, resolution, projector type, etc to help with the decision making process as well. Let me list the considerations and flesh out each one...

    Budget - This is perhaps the most immediate limiting factor. Obviously at the time I write this, the pricing will differ as time goes by which makes it hard for me to consider specific models. When considering budget however, one must factor in not only the price of the projector, but the price of a matching screen (a do-it-yourself screen is also an option), a mount for installing the projector to the ceiling, and cabling to the projector. Prices will vary greatly on each type of projector as well costing anywhere from a few hundred dollars for a used projector, to a couple thousand dollars for a new entry level projector, to a few thousand for a CRT, mid-range LCD, mid-range DLP, to ten thousand dollars and up for higher end LCD, DLP, CRT and LCOS projectors. In some cases, an outboard line doubler (or scaler) may also be needed. In effect, this increases the resolution of the picture being displayed so that the projector's maximum resolution can be utilized. A good projector will have decent internal scaling but if not, an external one can be used but this would need to be added to the budget as well.

    The screen & projector. 16x9 vs 4x3 - In order to determine which native aspect ratio (4x3 or 16x9) is better for your setup, you first need to know what source material you will be viewing more of, and where to make the necessary trade-offs. Many of the movies available on DVD (not all) for example are in widescreen format as opposed to 4x3 format. Most of the material broadcast on local cable TV is in a 4x3 format. HDef broadcasts are mostly in widescreen as well. If most of your viewing will be widescreen material then the native 16x9 resolution of a projector will serve you well. For instance, a movie like Toy Story which has a 1.78:1 aspect ratio will fill the entire 16x9 screen. Viewing the same movie on a 4x3 projector and screen will result in black bars on the top and bottom of the screen, and less of the resolution of the projector devoted to the movie. The flip side however comes when viewing 4x3 material on a native 16x9 projector and screen. In this case, you will get black bars to the left and right of the image. A third consideration to consider is most 16x9 material is of a higher quality than 4x3 material so choosing a 4x3 screen to view both widescreen and full frame on it will yield a widescreen movie with black bars on the top and bottom, as well as a blown up (large) 4x3 image that shows all of the defects of the 4x3 material. A complete article can be found at Projector Central for more reading... 4:3 vs. 16:9 - how to select the right format

    HT room dimensions, screen size, and projector "throw" - Room dimensions must be taken into account as well. The length of the room from the front to the back can come into play. The first thing that is important regarding screen size is that it is not recommended sitting closer than 1.5 times the screen width otherwise the image becomes too large to watch comfortably. Once the length of the room is known, you need to determine the screensize you would like to have, and if it will "fit" into the room. For instance, a 16x9 92" screen is 45" high and 80" wide so seating should be no closer than 1.5 x 80 = 120" or 10ft. You also need to determine if the particular projector can create an image of that size withing the boundaries (length) of that room and still have enough space behind for cooling purposes. This is also know as the projector's throw. Most rooms will have a high enough ceiling to accomodate the projector and screen but a very low ceiling may in fact rule out a possible front projection setup.

    Source material & resolution - Today's DVD resolution is 640x480. Some Hdef programming is broadcast at 720 lines progressively, or 720p, while others are broadcast at 1080 lines interlaced, or 1080i. DVHS's resolution is also 1080i and future formats like HD-DVD may also be this resolution. The resolution of the formats you watch, and the ones you would like to watch is another consideration. Projectors come in various 4x3 and 16x9 resolutions. I will list them with their resolutions...

    . VGA = 640 x 480
    . WVGA = 858 x 484
    . SVGA = 800 x 600
    . XGA = 1024 x 768
    . WXGA = 1366 x 768 or 1280 x 720
    . SXGA = 1280 x 1024
    . WSXGA = 1365 x 1024
    . UXGA = 1600 x 1200
    . QXGA = 2048 x 1536

    Obviously, the more pixels displayed, the less visible and smaller the pixels will be and the better the picture quality, all else being equal. Price tends to increase with resolution as well. Many projectors will "down-convert" a higher resolution to fit their native resolution but a projector that is capable of a higher resolution should be considered before one that has a lower resolution, all else being equal of course.

    Your HT room's ambient light, projector brightness & screen gain - Some of us are "fortunate" to have a room that can be totally light controlled (made pitch black even during the daytime), while others of us have room with lots of ambient light. Being able to control the amount of light in a room is very important, no matter what type of projector is used but a projector with higher brightness will be able to handle a room with ambient light better than a projector with low brightness. Many lower end projectors and some of the CRT units can have a brightness of 300 to 600 ansi-lumens. Essentially, these should be placed in a room that can be made totally dark. The better LCD and DLP projectors can be as bright as 1000 a.l. and some can be upwards of 1500-2000 a.l. Ambient light will wash out the colours and the blacks as well resulting in no shadow detail and rendering the picture un-watchable. Once you select a projector then a suitable screen must be selected to match it with an appropriate amount of gain. The higher the gain of the screen, the brighter the image on the screen and the more resistant the image is to a room's ambient light. A reputable home theatre store can usually recommend a suitable screen for a projector you choose but it helps to know the dynamics of the room, particularly how much ambient light it may have.

    Contrast ratio - What is contrast ratio? Contrast ratio is the range between the lightest and darkest light that a projector can produce. The higher the contrast ratio, the better a projector is capable of producing blacks on the image. This is where the better CRT projectors and the higher end DLP units shine. Make no mistake though, LCD technology with the higher end units is on par and should not be ignored either. In any case, those with a lower on/off contrast ratio vary anywhere between 250 - 600 a.l. while some are 600 - 1000 a.l. or higher.

    Inputs/connections - At a minimum, a projector should have composite video, s-video, and component video inputs. Some projectors will accept progressively scanned signals so this is important if either using a progressive scan DVD player of a HDef signal. Other connections include a 12V trigger for a motorized screen and a DVI port. A DVI port (digital video interface), if a projector is equipped with it, allows an outboard scaler or home theatre PC (HTPC) to be used to scale an image to the highest resolution that a particular projector can accept, and can result in amazing images. The most common type of DVI connection is the 15- pin analog DB15 VGA style of connector that computer monitors use. Some others have DVI-D which is a digital 24-pin variant. For more information on DVI, read this article from Dell.com...
    http://www.dell.com/us/en/arm/topics...s_2000-dvi.htm.

    Other features/considerations - There are lots of different features that may prove to be of use to a potential buyer. Some of those include manual/power focus, manual/power zoom, keystone correction, lens shift, inboard speakers and more. The last consideration I will mention is bulb life, something that must be kept in mind with digital projectors. The higher the bulb life the less frequently it will have to be changed. As this is an expense, a higher bulb life will be advantageous. Typically, bulb life varies between 1000-2000 hours. Some projectors offer an "econo" mode that lenghtens the life of the bulb by slightly reducing the light output.

    Conclusion - Once you consider all of the above criteria, a list of hundreds of potential projectors can get narrowed down to a few, or even one that is the best in your situation. There are many online websites that contain specifications that help with the decision making process. Onew thing to remember is that there are some projectors that may have lower lumen and/or contrast ratio specs than others but they are pretty much "spot on" right out of the box and require much less calibration to achieve the proper results. Then there are other projectors that have higher lumen and/or c.r. specs but by the time they are calibrated, those actual real-life specs are much lower. Also, most times, the contrast ratio cannot be achieved at the rated max lumen output of the projector. It is always best to demo a projector for oneself at a reputable local home theatre store rather than buy sight unseen. Your eyes are the best guide.
     
  20. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    When I put in a CD, it's SO MUCH LOUDER than a DVD- Why does this happen? Am I doing something wrong?


    Explaining this actually means a basic trip into the technical world of digital audio. Are you ready? Here we go...

    Digital audio has a hard maximum ceiling for audio. This level is known as "0". All sound in the digital realm is then measured in a scale using ZERO as maximum and working downward (-10, -20, -30 etc). Sound cannot be written to a digital audio format that exceeds this 0 maximum. So think of 0 as the absolute speed limit in the digital audio world.


    Now- movie soundtracks are designed to be dynamic. They want to give you all those big loud booms and hushed whispers....

    The idea of "dynamic" is simply that there is a big difference between the loudest sound and the quietest sound. But, like we said before- no matter what we're encoding- digital has a very hard limit of the maximum level something can be... So, in order to have room for dynamics- you can't make the loud louder- so what do you do? Well, you have to make everything else softer!

    So- movies are created to have their average overall sound level be low. If the average level is kinda low then this gives them plenty of room to get loud before they hit that digital maximum level (they call this headroom-- its the amount of room you have to go up before you hit your head on the ceiling- cute huh?).

    Movies are designed to have their average dialog level be about 25 or 30 steps below the maximum level available. That way, when they want to have some big dynamic special effect- they have room to go louder... So between the dialog (average level) and the loudest sound (max level) they have 30 steps of dynamics to use.


    Video games and CDs are often designed in a different way. Instead of being dynamic- they are squashed. Almost the entire signal is squashed down into a tight package- and the whole thing is just "loud" all the time. The average CD uses just the top 3-6 steps of available volume all the time. In other words- where movies have the ability of having 30 steps of dynamics to use-- CDs only use about 1/10th that much! They push the entire signal all the way up to those top 3 levels below the max- and thus it seems significantly louder than a DVD.


    If you could look at the waveform for a digital movie soundtrack, it would look something like this:

    [​IMG]
    Notice the average level is much lower- but has an occasional dynamic peak that hits the max level.



    If you could look at the waveform for a digital music soundtrack, it would look something like this:

    [​IMG]


    The same audio "squashing" process is used for TV broadcasts, Radio Broadcasts and VHS (although for slightly different reasons)-- you'll find they will also be "louder" on your system. The case isn't really that one is louder than the others (like I said above, they all have relatively the same maximum level)-- it just appears "louder" because all the signal is squished as close to the top as possible... while others set the average level lower to have room for dynamics.

    In closing, there is nothing wrong with your receiver or equipment. The difference in volume is normal and exactly how it should be given the nature of the different audio types.
     

Share This Page