| AudioREVIEW's Forum Archives - Amplifier-Preamplifier |
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|   ProLogic,ProLogic 2 and DTS | pegasusxls2
Aug 28, 2002 4:16 AM | | Can anyone explain the differences? |
| re: ProLogic,ProLogic 2 and DTS | wanderingbob
Aug 28, 2002 8:15 AM | | Dolby Pro Logic is a method for "matrixing" two channels of audio information to route information to surround speakers. Dolby Pro Logic is not "discrete" - that is, the surround channels aren't actually independent channels on the DVD or VHS tape (VHS tape does support Dolby Pro Logic).
Dolby Digital and DTS are "discrete" sound formats with at least 5.1 channels - two front channels, a center channel, two surround channels, and a subwoofer (the ".1"). With Dolby Digital (DD)and Digital Theater Sound (DTS), the DVD actually has at least 5.1 independent channels (DD and DTS aren't available on VHS tape). DTS offers an improvement over DD because DTS uses more bandwidth (data storage on the DVD) and therefore compresses the audio data less than DD. DD uses "psychoacoustic compression" whereas I beleive DTS does not.
Later offerings (Dolby Digital EX, DTS ES) may offer a back center channel or both side and back surrounds (6.1 or 7.1), but essentially operate the same as the earlier versions.
If you want to talk to some real DD and DTS experts, try Richard Greene and "Sir" Terrence "the Terrible One" on the Home Theater forum.
Bob Gardner
wanderingbob@yahoo.com |
| re: ProLogic,ProLogic 2 and DTS | A
Aug 28, 2002 8:57 AM | | Here is a short explanation of most of what interests you:
http://dolby.custhelp.com/cgi-bin/dolby.cfg/php/enduser/std_adp.php?p_sid=og7GUQng&p_lva=&p_faqid=136&p_created=1015027785&p_sp=cF9ncmlkc29ydD0mcF9yb3dfY250PTYxJnBfcGFnZT0x&p_li=
You should probably also read:
http://www.dolby.com/ht/Guide.HomeTheater.0110.html
Both Dolby Digital (DD) and DTS can have "5.1" discrete (separate) channels, but Dolby Digital may have fewer channels (DTS can also have 6.1 discrete channels). So when you buy a DVD, if you want to know how many channels of sound are on the disc, you will need to know more than just that it has DD.
Both DD and DTS use data compression to fit all of the channels on the available space. DTS uses less compression. However, that does not necessarily mean that it sounds better; the quality of the sound is very dependent upon the way the data is compressed, not simply how much it is compressed. As far as I know, there have been no proper, independent, demonstrations that either format sounds better than the other. If you want to read what DTS and Dolby claim about this, see (these are pdf files; something like Adobe Acrobat Reader will be needed to read these; Adobe Acrobat reader is available as a free download):
http://www.dolby.com/tech/mp.in.0103.DigitalVsDTS.pdf
http://www.dtsonline.com/dtsposition.pdf
http://www.dtsonline.com/dolbyrvu.pdf
Not surprisingly, Dolby says Dolby is better, and DTS says DTS is better. Most people "decide" one is better based on improper testing or flawed reasoning; they typically say that DTS is better because it is less compressed, which is something that is not necessarily true, or they listen to two soundtracks on a few DVDs in both DD and DTS. There are two problems with this: First, people typically do not level match the two (which is necessary because if one is slightly louder, people subjectively tend to prefer the louder one). Second, there is no reason to suppose that the two soundtracks are the same mix/master, so there could be differences before they are encoded into DD and DTS, and these differences may be heard later. Such differences would make it impossible to judge which of the two formats was better, because the mix in one of them may be better (for more on this idea, listen to The Beatles' Yellow Submarine on CD, both in the original release and in the newer "Songtrack" release; both are CDs, but the mix is different and they sound very different from each other).
For more complete answers, see:
http://www.dolby.com/
http://www.dtsonline.com/ |
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