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SACD flawed to begin with? S&V David Ranada's article:

Discussion in 'Music' started by JediFonger, Jul 7, 2006.

  1. JediFonger

    JediFonger Producer

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    P. 82 of the July/Aug Sound and Vision Magazine, David Ranada writes:


    those 2 points were news to me. although it's hard for me to hear the diff. between the CD & SACD, does this mean that SACD is still introducing noise or will that *always* be inherent in all digial sound?

    the second point is that what does encoding have to do with decoding?
     
  2. JeremyErwin

    JeremyErwin Producer

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    DSD is fundamentally different form PCM.

    PCM: At this point in time, the signal has this particular value.

    DSD: At this point in time, the signal is less than or greater than the last sample.

    With a bit of creativity, you could argue that DSD was somehow more similar to vinyl records.

    But PCM was a well established technology. Hundreds of thousands of mathematicians and engineers had published reams of papers on the manipulation of PCM and similar forms of data. It's relatively trivial to analyze the frequency components in a piece of PCM data. But DSD?

    You could convert the DSD into PCM, apply the FFT, do some manipulations, apply an inverse FT, and then convert the result back into DSD. But Sony claimed that some benefits of DSD were lost during the conversion process. You could also develop a new algorithm to work on the DSD directly, but such development costs time and money.

    The benefits of SACD, as far as I'm concerned, lies in the depth of the music library.
     
  3. Kevin C Brown

    Kevin C Brown Producer

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    I actually think the benefit of SACD, unlike DVD-A, is that you don't need a freaking video display to play the discs. [​IMG]

    I have also seen the noise argument put forth for SACD. I see two problems with that: a) The noise is high enough in frequency that humans can't hear it, and, b) I have enough SACDs and DVD-A's to compare that if there is extra noise there, I don't hear it.

    I have also heard the contention that the presence of that noise does make SACD sound more analog. I don't think I believe that either. Both SACD and DVD-A sound more "analog" simply because both are a much better digital representations of the original analog waveform than CD is.

    I have heard that the noise is automatically filtered out if you convert to (high rate) PCM before going to analog. Most i.Link and HDMI connections result in this if you're going to use any extensive BM or TA in the receiver or pre/pro. And, players like the 3910 and 5910 that do extensive BM and TA themselves also do a DSD to PCM conversion too.
     
  4. gene c

    gene c Producer

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    And to me, the biggest problem with SACD is the lack of video content! Oh well. Different strokes for....
     
  5. Felix Martinez

    Felix Martinez Screenwriter

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    I've had my projector for 5 years now, and rarely fire it up to play DVD-As - unless I want to see the video content. I just hit stop when the disk spins up and then press play. I can browse the Groups with the remote as well. Works this way with my Onkyo sp800 universal player and Panny RP-91.

    But...I cannot toggle between the stereo and m/c layers of SACDs...I have to go to the Onkyo set up screen for that - and there I do need a monitor.
     
  6. ChristopherDAC

    ChristopherDAC Producer

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    Mathematically, the dynamic range of a one-bit (delta) modulation system such as DSD falls off with increasing frequency. Simultaneously, because the "slew rate", or size of each up or down step, is fixed, there is a great deal of "hunting" involved in following the slope of the input waveform. It's this latter phenomenon which generates the noise inherent in the process. The noise is greatest at high frequencies, but it actually extends down to the very lowest frequencies. In essence, while the "image noise" produced by spurious frequency components in a PCM system is all above the sampling frequency [twice the maximum reporduced frequency] as long as a proper anti-alias filter is used, in a one-bit system a large fraction is actually within the passband. It is for this reason that SACD players incorporate a 50 kHz brick-wall filter [thus limiting the frequency band to about the same as 96 kHz PCM on DVD-A], to avoid the high frequencies damaging your amplifier. There was a period when 1-bit analog-to-digital and digital-to-analog conversion circuits were widely used in recording and reproducing equipment, with internal conversion to or from PCM, because they were cheaper and easier to build than actual multibit ADCs and DACs which would achieve 16-, 20-, or 24-bit performance. Sony's papers and promotional materials tout the advantages which DSD does have when used in an environment of 1-bit devices, by avoiding multiple stages of PCM-delta conversion. To the best of my knowledge, however, while 1-bit ADCs and DACs are still used in the majority of low-end and general consumer products, they have fallen out of use in professional and audiophile devices, except those dedicated to SACD use! Incidentally, for a quality comparison, I read an article about the remix of — I am fairly certain — Brothers in Arms, the Dire Straits album. The recording engineer described his experiences comparing the various audio formats, and it came out to something like : 24/96 PCM is best, then 1-inch 30ips analog tape, then DSD, then 15ips tape.
     
  7. Manus

    Manus Second Unit

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    " It is for this reason that SACD players incorporate a 50 kHz brick-wall filter "

    Funny thing about this was the dummy who worked on the Sacd of 'Dark side of the moon' showed his ignorance by actually claiming at the launch that this was a flaw of the Dvd-A format !

    " I actually think the benefit of SACD, unlike DVD-A, is that you don't need a freaking video display to play the discs "

    My Meridian player I just press play and the default mlp 5.1 track starts playing ; pressing the Audio button changes between the Audio tracks if required and Video is only really required if you want to view extras.

    ~M~
     
  8. gene c

    gene c Producer

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    Different players, and different discs, handle the start-up differently. On my most played DVD-A's I remember which button or two to push so turning on the display isn't always needed. My new H/K 47 dvd player also has an audio button on the remote that switches between formats "on the fly", or so it says in the manual. Haven't tried it out yet though. BTW, with what you must have payed for that Meridian, it should bring you a cup of coffee and the newspaper in the morning too! Yes, that's envy talking.
     
  9. LanceJ

    LanceJ Producer

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    From the pro audio discussion forums: supposedly because of the noise inherent in DSD, DSD>PCM>DSD conversions need to be limited to less than @5. Past that, then all that noise starts to reveal itself by giving the music a "veiled" quality, which is most apparent in the higher frequencies.

    And on a personal note, I don't much trust a system that only uses data that says "change" or "no change" to describe a waveform.

    BTW: dvd-audio discs can authored so they don't need ANY onscreen navigation to operate them or any video portion *period*. For some reason, except for that Elv1s dvd-audio (a BMG title, before Sony bought them), the labels seems to think everyone likes farting around with TVs to get to the stereo or bonus tracks on the disc. The audio button does usually work with most newer discs to do this, but AFAIK the "Group" button was really the button that was supposed to be used to change between sets of tracks. But for some reason only a handful of dvd-audio players include them, usually just Panasonics (who designed most of the dvd-audio format's hardware), JVCs and Denons.

    Considering that the head of the Dvd-Audio Council is also the CEO of Silverline, IMO I'm totally not surprised the standards for dvd-audio are so effed up.
     
  10. Manus

    Manus Second Unit

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    " it should bring you a cup of coffee and the newspaper in the morning too! "

    No sugar, and the crossword and sudoku's done so I can impress any visitors [​IMG]

    The sad thing which is becoming apparent in this thread is that we should never have had to choose between these formats. Like dts to Dolby ,and Bluray to HD-Dvd they were 'sideways' technologies that each attempt to achieve the same outcome.

    Frustrating
    ~M~
     
  11. gene c

    gene c Producer

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    I see your point. DVD-A vs. SACD wasn't a war but genocide. The exception is DD and DTS. They are both thriving because they are being supported by both sides, hardware and software. And they are pushing each other to our benefit. How far along would Dolby be without DTS on their bumper? Having choices is usually a good thing. Unless the field is watered down to a point where nothing succeeds. And that can happen with only two in the field. With declining sales, will there be a consolidation/shakeout in the avr and speaker industries? And I wonder which one, SACD or DVD-A, would have had the best shot at making it had one been allowed to go solo? Now the Blu-Ray-HDD thing is a shame. They should have worked something out.
     
  12. Chris Gerhard

    Chris Gerhard Screenwriter

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    I love SACD and have read some of the complaints about the shortcomings. I think hybrid SACD had the best chance of success, based on sound quality and the fact the discs play in every CD and DVD player. For the limited group that want the high resolution surround or stereo, of course it required an SACD player. DVD-A had such terrible quality control from its biggest supporter, 5.1 Entertainment Group with many truly horrid releases. I sure don't hear the shortcomings of SACD compared to DVD-A, but I accept there must be some since it has been discussed by very knowledgeable people. Bottom line, I have over 100 SACD's and about 60 DVD-A's and several players and plan to play the formats for the rest of my life.

    Chris
     
  13. Manus

    Manus Second Unit

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    " How far along would Dolby be without DTS on their bumper? Having choices is usually a good thing. "

    Unfortunately, in this instance , I feel that it has worked against us.Having 2 essentially similar soundtracks (Dd/dts) taking up space on SD-Dvd convinced people that it did not have enough room and enabled the idiots to rush 2 new formats to market well before they were ready.

    I think its a pity that Hi-Rez Mch. music has been marginalised as I really the fact that you have to sit down and really listen just like you did as a kid. Its very relaxing.So much music passes us by because of our frenetic lifestyles.

    Chris,Never mind the tech , enjoy your music [​IMG]

    ~M~
     
  14. PeterTHX

    PeterTHX Cinematographer

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    Dunno. Dolby was pretty good about innovation to begin with. Introducing Dolby A, then 70MM baby boom, then split-surround, then SR, etc.

    With the introduction of Blu-ray/HD DVD we get Dolby Plus & TrueHD. I'm pretty sure this would have happened with or without DTS.
     
  15. Rommel_L

    Rommel_L Second Unit

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    ...not a damn thing.

    Good bass management (or lack thereof) depends on how well the album was produced. Speaker-distance compensation? Compensate for what? WTF does that even mean? The writer readily blames the medium/technology than how the music was produced. As the old adage says, "Garbage in, garbage out..."
     
  16. Lee Scoggins

    Lee Scoggins Producer

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    There are really no problems with the noise shaping in DSD as they occur in the ultrasonic range and most recording engineers I speak with have not heard it.

    As for DSD, I think with audio you have to go with implementation and listen critically to the results. I have worked on dozens of record albums, most of which have have recorded in minimalist audiophile live to 2 track process.

    Based on my experience, I find that DSD is more natural than even 24/96 or 24/88.2 PCM (which can also sound terrific). It seems to my ears to have a more analog like sound. I think this is due to higher sampling rate and to the simpler signal recording path.
     
  17. JeremyErwin

    JeremyErwin Producer

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    So, I take it that your home theater consists of five identical, full range speakers, arranged equidistantly from the listening position, with a Subwoofer to reproduce the LFE channel?
     
  18. Rommel_L

    Rommel_L Second Unit

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    Is this for my speaker-distance technobabble comment? To answer your question, no. I have identical front l/r speakers, matching center and rear l/r speakers and a subwoofer for LFE. Since the room is NOT for critical listening, the speakers are configured for a wide listening AREA (as in a movie theater), and to compensate for room size, acoustics, etc.
     
  19. gene c

    gene c Producer

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    I'm sure it all would have happened eventually. But with a little competition, things tend to occur a little faster.
     
  20. JeremyErwin

    JeremyErwin Producer

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    Suppose that a classical piece was recorded in a church with reverberation. The singer' voice echos off the rear walls, and in the sacd recording, the sourround speakers are used to recreate this ambience.

    If the listener is closer to the surrounds than he is to the front, he will will hear the echo before its time (and this will often have the effect of muddying the vocals.). If he is closer to he front speakers than he is to the surrounds, the echo will be heard somewhat later than appropriate, giving the false impression that he church is somewhat larger than it actually is. Distance compensation adds microsecond delays so that no speaker is heard before it's time.

    And, of course, if the speakers are at different distances, they must be calibrated so that no one speaker sounds louder than the others. (but this is trivial).

    Modern 5.1 soundtracks use 5 full range tracks and one low frequency effects track. The lfe contains explosions, dinosaur footsteps, and other elements that would benefit from an extra 10 db headroom. When less than full range speakers are used, the frequencies lower than the crossover slope are filtered out, and added to the lfe to produce a subwoofer channel.

    It is inappropriate to high pass the full range channels at the mixing stage. The listener should be able to apply his own bass management, crossing over at a point which is optimal for his speakers, his room, and his ears. If bass management is applied in production, it removes a bit of flexibility.

    Of course, that's ideal. Most players use a fixed crossover point when speakers are set to "small". I think it's usually 120 Hz.

    Yes, yes, 80 Hz is some kind of standard-- but standards cramp flexibility.
     

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