If you already know about 5.1 standards, then skip to the section labelled "For the experienced..."
For movies, AC3 and DTS are now the standard for DVD because there is better separation of the surround channels vs. Prologic 5.1. And because the THX standards are so improved over past implementation, multi-channel SACD is now using roughly the same post DAC implementations and specifying 5 full range speakers instead of 2 full range and 3 satellite sizes. If we remember that SACD stereo is supposed to transduce 20-100Khz and at least 20-50Khz, that is a pretty stringent standard. (Yes, I believe the the standard is only 20-20KHz for 5.1 SACD, but cannot recall with certainty.)
Tomlinson Holman has been the guru of surround since Hafler in the 70's and Dolby in the 80's. His work AES related work has (so far) been the basis of most of the recent standards. You'll have to do some Googling, but it's all there.
http://www.tmhlabs.com/research/research.html
It should also be noted that 5.1 is completely unnecessary for listening to material recorded in stereo and can even destroy the presentation originally intended by the mixing engineer. With the right decoding, it is useful, but not needed for material that is stereo music with some surround encoding. There is a boatload of material on what matrix system is compatible with another so, sorry, yet more googling.
Finally, I think it is important to say that cheap 5.1 doesn't come close to even mid-fi stereo for soundstage, object placement and realism. It is fairly common for the quality of the analog stages to be the limiting factor in most consumer setups. And, they will continue to be until consumers get some discerning ears.
For the experienced,
nothing beats a high quality 5.1 decoder or processor. Most HT receivers at the US$750 level have decent processors, but don't have matching analog output until about the US$1500 price bracket. (IMO, as you can tell, it is not the processing, but the analog stages that need to be improved. Not A vs D but quality of both should match.)
Most pro-sumers make the mistake of getting a DVD player that has all sorts of features (DTS, 24/96, etc.) and then hooking it up to their HT receiver digitally. At that point, all those great specs are lost because the receiver is only 16/48 (or whatever) and has really noisy and distorted (pre)amps. They just bought this really expensive transport and they didn't know it. And, it probably doesn't have better jitter specs than the cheap DVD's. (Of course, the video is better, but that is not at issue here.)
This is why I bought the Sony NC-650V. It is an SACD/DVD/CD 5-disc changer. Since the analog output stages are shared, they have to be high enough quality for the SACD. They are not ES-series quality but way better than practically everything in the same price range up to about double the price. I not only get the wonderful analog outs, but 6-channels of analog output. With decent amplification and speakers, which is cheaper than any comparative HT set-up, I get HT at a mid-fi price. If I play a CD only the L/R mains give me sound. Too bad it is no longer in production. I think they still make the NC-700 series with 5.1 analog outputs.
Source: Sony NC-650V
L/R mains: Yorkville YSM1-p active studio monitors
L/R rear: Tannoy Proto-J studio monitors/Marantz 1530
Vol ctrl: Teac 2A 4-buss mixer
Finally, I think speaker placement is critical. In each SACD 5.1 case, there is usually a little diagram that shows the usual equilateral triangle with the addition of a circle. The ideal location of the rear surrounds is supposed to be at about 120deg relative to the centre channel with all speakers right on the circle for equal distance to your head. This ideal 5.1 set-up may not coincide with your ideal stereo set-up due to room reflections, bass boost, phase cancellations, etc. I believe this is the greatest problem when comparing an audiophile HT in both modes.
Dave: If you are having problems with your centre channel, it might be because you don't have the required delay for the surround channels. On any 2.0 matrix decoded to 5.1, there must be a delay of about 15ms total for rear channels. Without it, the brain is not fooled into thinking that the surround channels are behind. If the stage collapses relative to the LR mains, then you may require a digital delay (1 ms / foot) as a result of the distance from listener to speaker. I find that DVD requires a centre to locate dialogue properly at the screen. Even with my virtual centre there is a lag of about .25ms between the mouth movement and sound and I cannot compensate with my 1ms delay resolution.
Bill: In a nutshell, the advantage of 5.1 discrete over 2.0 matrix is the channel separation. And this is assuming that the quality of the recordings are the same, yielding the same low noise, and frequency range.
:)ensen.
PS: I try to be helpful and for me it is unhelpful to be incomplete. Thus, I tend to be pretty verbose so my apologies for any annoyances.
HT vs Stereo - an issue not covered?
) if you have the entire package, including a large enough room to get the full effect of the Enterprise coming from behind and passing over your head.
