Audigy review

[Guest]

Just a few audio-related notes.

1) Tom refers to the center channel in 5.1 sound as for speech. Although it is true that normally all dialogue goes into the center channel, a lot of other sound goes there as well. It is, in fact, the main channel in most surround mixes.

2) What he refers to as the "sub-bass" channel is correctly referred to as the low-frequency effects channel.

3) The card's frequency response plot is shockingly bad. I wonder if some processing mode was inadvertently engaged during the test.

4) The noise and dynamic-range measurements demonstrate that the 24-bit A/D and D/A converters are mere window dressing. Performance is no better than one would get with decent 16-bit converters. (In fairness, I have yet to see specs for any A/D or D/A converter, 24-bit or otherwise, that indicate better than 20-bit resolution, which is about 120-dB S/N. The physics of the situation are daunting beyond that point; I doubt that one could get true 24-bit resolution without running everything in liquid nitrogen to get the thermal noise down.)

 

[FatBurger]

First, Tom didn't write the review. It was written by two people named Stéphane Moreau and Stéphane Kauffmann. Just in case you didn't realize that.

1) They state "the card distorts the sound normally intended for the central satellite, or the voices in films."
Yeup, I think you're right on that. Oh well, small error at least in my opinion.

2) American terms, European terms. Don't ask him to look under the hood of your car, tell him to look under the bonnet of the car. This might not be the case, but it's my guess.

3) I was also wondering about this. It just doesn't seem to fit. Are you familliar with similar tests on different cards? I am not, maybe you can help clear that up.

4) I'm sorry, I'm missing your point in this one.

<font color=green>I post so you don't have to!
9/11 - RIP</font color=green>

 

[Guest]

1) Thanks for the catch. I noticed my error after I'd made the post, unfortunately.

2) You may well be right. I brought it up only because many people think the LFE is a subwoofer channel. Although it usually is reproduced by a subwoofer, it doesn't have to be.

3) Yes. Take a look here: http://www.pcavtech.com/soundcards/reports/index.htm
Really good cards are within +/-0.1 dB up to 20 kHz--not +0.5, -2.5 to 16 kHz with huge ripples from 2 kHz up!

4) A lot is made of the fact that the board has nominally 24-bit converters, but the performance is, at best, a little shy of what you would get from ideally performing 16-bit converters. So the 24-bit converters serve only a marketing function on this board, not a technical one. The secondary point is that to a considerable extent "24-bit" is strictly marketing hype whenever it comes up, since it's pretty much impossible to make a converter that delivers true 24-bit resolution (about 144 dB dynamic range).

 

[FatBurger]

Ok, that's what I thought you were saying, but I wasn't sure.

Oh well, only the second audio review on Tom's, I guess they all deserve some slack.

<font color=green>I post so you don't have to!
9/11 - RIP</font color=green>

 

[Guest]

You're right. I copied my original post to the TH editors, in the vein of constructive criticism. Audio is a surprisingly complicated subject, and few of the people who write about it really understand the technology very well--a situation that has gotten worse rather than better over the years. Tom's Hardware is an excellent site; I expect the audio reviews will get better over time. The one on the Audigy was generally good, except mainly for the praise of the card's frequency response.

 

[FatBurger]

Agreed. They also didn't mention what speakers were being used (that I noticed), which would make a huge difference.
Time to hook up some Genelec studio monitors, or at least the Mackies. That'd make a huge difference.

My suspicion is that the speakers were causing the bad frequency response, although I could of course be wrong.

<font color=green>I post so you don't have to!
9/11 - RIP</font color=green>

 

[Guest]

I would think they would measure the electrical frequency response at the line output.

 

[FatBurger]

Could be, but it's impossible to tell for certain.

<font color=green>I post so you don't have to!
9/11 - RIP</font color=green>

 

[Guest]

Response measured from speakers normally would be a *lot* messier looking.

 

[FatBurger]

Not necessarily. Ever seen frequency response charts from the studio monitors I mentioned? (Genelec and Mackie)
Pretty flat

<font color=green>I post so you don't have to!
9/11 - RIP</font color=green>

 

[Guest]

The curves they publish in their spec sheets are no doubt very heavily smoothed. No speaker on earth has response as clean as that from a purely electronic device. There are always lots of small (sometimes large!) driver resonances. The raw response plots of even the best speakers tend to be pretty ragged looking.

 

[Guest]

Pray that they do. Error introduced by first converting from an electric signal to a air pressure signal, and then back might totally swamp what was being tested in the first place. Hopefully the signal was routed straight from the card to the test equipment. I don't think the testers could be that incompetent, and still have their material published, on this site. From what I've seen Tom and crew seem very sharp, and I guarantee they would not allow this kind of thing to occur.

 

[Guest]

The curves (awful as they are) would not look anywhere near as clean as they do if they were measured via speaker output.

 

[Guest]

Mr DIggs I agree with all you said about this review some of it was sketchy. Especially the frequency response graphs I mean come on +0.5, -2.5 dB? Is that meant to be good?

Does anone think that the D/A convertoers were being excited at all during the noise measurements?

WHat about the upsampling algorithms? are they any good?