Difference between Hi-Fi and Dolby?

Discussion in 'TV on DVD and Blu-ray' started by DeathStar1, Mar 23, 2006.

  1. DeathStar1

    DeathStar1 Producer

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    As someone who's still learning, this may sound like a stupid question, but here goes...

    What's the difference between Hi-Fi stereo on a VCR, and Dolby Digital 2.0 on a DVD? Are they the same sound quality, different name, or is one better than the other?
     
  2. Jeff#

    Jeff# Screenwriter

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    Well, historically Hi-Fidelity stereo came out in the 1950s and was only available in some movie theater sound systems and record player consoles back then. It wasn't really until the early 1970s when home stereo systems lived up to their names.

    Dolby Laboratories created home video stereo and also for theatre equipment starting in the 1980s. Dolby Surround and Dolby Pro Logic were two of the earlier ones, and they're still used. Then in the 1990s came Dolby Digital. I think there are differeces in the sound levels and variables between sound (dialog), sound effects, and music. Most of the DVDs I watch have the default sound setting at Dolby 3.2 to 1.
    2.0 is the next setting, and 3.2 to 1 is superior. I recently purchased an RCA TV / DVD combo player manufactured in August 2005, and it has a 3.5 audio setting which is what I use all the time. I'm not a tech guy or an expert on this subject, but if I'm reading the info correctly on the on screen display that's what it looks like (nothing in the owner's manual about that). It works quite well, and the audio for my copy of Beverly Hills Cop II produced in 1987 sounds just as excellent as anything made today.

    I don't like how so many films made over the last 25 years BLAST the music and background sound FX at twice the volume of the dialog. So for home viewing, that's a good reason for me to buy an equalizer. [​IMG]
     
  3. Jack Briggs

    Jack Briggs Executive Producer

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    Jeff, don't know 'bout you but I was thoroughly enjoying two-channel stereo in the mid-1960s. It was the real thing, buddy.
     
  4. Jeff#

    Jeff# Screenwriter

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    I was born in 1968, Jack, so no comment. [​IMG]

    Have to make a correction on one item with my DVD player's audio channels: It's not 3.5 to 1 but 5 to 1. Since I only have 2 stereo speakers built into my TV, that soundtrack setting probably works best with a 5 speaker system.

    The "3" part I cited was just the marker that appears on my player's on-screen programming next to it.
     
  5. Mark-P

    Mark-P Producer

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    Hi-fi stereo on a VCR is a process called AFM (Analog Frequency Modulation) but has very good sound characteristics. The tracks are recorded at a slanted angle that nearly cover the whole width of the videotape. Since the Hi-fi tracks are recorded at a different angle that the picture tracks, they don't interfere with one another. Dolby noise reduction is not employed by Hi-Fi because there is no tape hiss like there is in linear soundtracks.

    Dolby Digital 2.0 is of course digital sound, much like a CD but with compression. Digital sound has better frequency response, more dynamic range, less signal-to-noise ratio, and other improved specs than even I don't understand. So while it is not quite up to the standards of the uncompressed digital sound of a CD, it is still better than VHS Hi-Fi
     
  6. David Von Pein

    David Von Pein Producer

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    Someone can now provide an essay on the detailed differences between Hi-Fi Mono and "Normal"/"Standard"/Non-Hi-Fi Mono on VHS.

    As far as I can ascertain, the only discernible difference between a Hi-Fi Mono track and a Non-Hi-Fi variant of same is a slight decrease in background hiss on the Hi-Fi variant. Is there something more than just this that sets the two apart?

    Thanks...and Godspeed. [​IMG]

    BTW -- IMO, 2-Channel Stereo and Dolby Surround on VHS tapes sound excellent most of the time...and, in some instances, I think the VHS counterparts of a particular soundtrack actually sound better than their DVD cousins...probably due to the audio on VHS being recorded at a much higher volume level.

    I realize that less distortion results from the lower-level-encoding placed onto DVDs; but to the untrained ear of Mr. & Mrs. Average Movie Buyer, the lower level of the sound probably equates to "Not As Good".

    (Does that mean I'm only "Average"? Dear God! Mother! Blood! Blood![​IMG])
     
  7. Will_B

    Will_B Producer

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    Heck yes, something more sets the two apart. The HiFi tracks have much greater fidelity than the linear audio track.

    I don't know the technical specs, but as I recall, back in the day if you didn't have one of those new-fangled "DAT" recorders, you could use the HiFi tracks of a VHS as a very high quality recording medium. They were an admirable substitute for high quality reel-to-reel tapes. They are better quality than audio cassettes.

    In contrast, the linear audio track on the edge of a VHS isn't even as good as an audio cassette, though they tried to make it adequate by applying Dolby to it.

    If you haven't noticed a difference in sound quality between HiFi and linear audio (aside from the noise floor), perhaps you are listening to a HiFi VHS tape that was copied from a linear audio VHS tape and thus has only the low fidelity of the original.
     
  8. JeremyErwin

    JeremyErwin Producer

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    jeff, usually people say "two point oh" or "five point one".

    There is a standard scheme for describing the channels of a movie soundtrack

    fronts/rears.lfe

    A 5.1 soundtrack would be displayed in this format as 3/2.1

    THX EX and DTS ES soundtracks are usually wriiten as 3/2:3.1, as the third rear channel (the rear surround) is matrixed in with the left and right surround. This serves to differentiate from a true 6.1 format, such as DTS ES Discrete. This soundtrack format is displayed as

    3/3.1

    Sometimes, this code is useful for differentiating, for example, the two types of "4.0" soundtracks: 3/1.0 describes a soundtrack with a mono surround, while 2/2.0 describes a quad mix (sans centre).

    Hi/Fi is an analogue stereo soundtrack. The tracks can be mono, straight stereo, or dolby surround.

    Dolby Digital 2.0 is a means of lossily compressing a stereo or surround track, often at very low bitrate, in which case, it can be very much inferior to an HiFi, or Linear PCM (uncompressed digital audio). In rare cases, it is possible to compress out the phase information, destroying the dolby surround effect.
     

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