How can you tell how good a sound card's DACs are?

[Ken90630]

Hey, All,

In reading about sound cards recently, I've seen some guys talk about the DACs (digital-to-analog converters) being a big factor in their analog output sound quality and how some Via HT-24S based cards are better than others because their "DACs are better."

But, I've never seen anyone mention how they know the DACs are better. How are they determining this, and how can a person tell how good a given card's DACs are? Are there particular brands of DACs, or certain kinds of circuitry in them that vary, or ???

Maybe a dumb question, but I'd like to understand this better. Any educatin' I could get here would be much appreciated.

PS: For purposes of this discussion, I'm mainly interested in the DACs found in the Via HT-24-based cards. I'm not looking for sound card recommendations with this thread -- I really just want to get a better understanding of how DAC quality is determined. Thanks.

 

[Matthias99]

Originally posted by: Ken90630
Hey, All,

In reading about sound cards recently, I've seen some guys talk about the DACs (digital-to-analog converters) being a big factor in their analog output sound quality and how some Via HT-24S based cards are better than others because their "DACs are better."

But, I've never seen anyone mention how they know the DACs are better. How are they determining this, and how can a person tell how good a given card's DACs are? Are there particular brands of DACs, or certain kinds of circuitry in them that vary, or ???

Maybe a dumb question, but I'd like to understand this better. Any educatin' I could get here would be much appreciated.

PS: For purposes of this discussion, I'm mainly interested in the DACs found in the Via HT-24-based cards. I'm not looking for sound card recommendations with this thread -- I really just want to get a better understanding of how DAC quality is determined. Thanks.

Well, there's a couple things you can do.

For starters, you can just look at the chips on the card and see what brand/model they are (unless they are unlabeled, but sometimes you can figure out what they're using by looking at press releases/spec sheets, etc.) Certain models/brands/types of DAC are better than others. If the board maker is skimping on the hardware, it's probably not gonna sound all that good.

If you don't know what hardware it's using, or you want to actually test the card as a whole (maybe it's using a new chip and you don't know how it will perform), I would imagine the best way to test would be to play back a 'known' reference digital audio source (such as an audio CD or WAV file), and record the analog outputs with an oscilloscope (or other high-resolution capture device, such as the line-in on a high-quality soundcard). You could then compare the output waveforms to a reference output and see how much they differ.

Finally, you can do subjective testing -- hook two soundcards (or a soundcard and a reference source) up to an identical set of speakers and play the same material on them. Of course, subjective testing is (by definition) subjective, and not as precise. But this is sort of what counts overall, since at the end of the day you're presumably listening to something with your ears, not watching the output of your sound card with a scope.

 

[Ken90630]

Thanks for the reply.

For starters, you can just look at the chips on the card and see what brand/model they are (unless they are unlabeled, but sometimes you can figure out what they're using by looking at press releases/spec sheets, etc.) Certain models/brands/types of DAC are better than others.

Okay, so reviewers are presumably looking at the chips on the card (or on press releases/spec sheets), like you say, to see what brand/model DACs are on there. That obviously makes sense. :thumbsup:

I guess my question that follows then would be which models/brands/types of DACs are considered, by some sort of accepted consensus among those in the know, to be the better ones? I can't recall reading any reviews where the reviewer says something like, "The ABC brand card has the XYZ brand/model DACs, which are _________ (insert quality assessment here)." They usually just say something like, "The ABC brand card has better DACs than the DEF brand card." So I guess folks like us just basically have to assume that they know which DACs are the best and are making the right call? I might be more or less comfortable with this if I were reading a professional review, but a posting by Joe Anybody on Any Computer Hardware forum could be anywhere from way off to spot on (or somewhere in between).

I would imagine the best way to test would be to play back a 'known' reference digital audio source (such as an audio CD or WAV file), and record the analog outputs with an oscilloscope (or other high-resolution capture device, such as the line-in on a high-quality soundcard). You could then compare the output waveforms to a reference output and see how much they differ.

Yeah, I agree, but I don't have an oscilloscope, nor would I really have the time to go to those lengths to do the testing myself. I'd rather just read a credible review from a skilled pro who knows what he's doing and has that equipment (naturally) .

Finally, you can do subjective testing -- hook two soundcards (or a soundcard and a reference source) up to an identical set of speakers and play the same material on them. Of course, subjective testing is (by definition) subjective, and not as precise. But this is sort of what counts overall, since at the end of the day you're presumably listening to something with your ears, not watching the output of your sound card with a scope.

Yeah, I agree again. It would just be my preference to not have to buy two cards and do the testing. (I don't have a lot of free time these days.) I'd rather be able to read a few credible reviews and be able to buy based on a know fact that Sound Card A has the ABC brand/model DACs and is thus gonna have better quality analog output than Sound Card B with the DEF brand/model DACs. Does that make sense?

I guess what would really help me now is if anyone happens to know which DACs are considered to be the better ones. That way, like you say, Matthias, it would just be a matter of identifying the DACs on a given card and I'd be good to go. Anyone know which DACs are considered to be best right now vis-a-vis the Envy 24-HT cards?

Thanks a lot for the info.

Ken

 

[Matthias99]

I'm not really one of those crazy home-theater-audiophile types, but the folks over at AVSForum are.

I couldn't tell you offhand which DACs were "better", other than finding a spec sheet for the chips and comparing the ratings (bandwidth, SNR, bit depth, stuff like that). I think you'll probably find that a lot of "skilled pros" don't necessarily know a whole lot more than the "average joe" about computer-oriented stuff like this (at least if their background is in home theater/stereo equipment).

 

[Ken90630]

I'm not really one of those crazy home-theater-audiophile types, but the folks over at AVSForum are.

Nor am I. :laugh: I'd characterize myself as a "sensible audiophile" -- very interested in quality sound, but not to the point of being obsessive about it or spending zillions of dollars to achieve it. I'll check out that link to the AVS Forum though.

I couldn't tell you offhand which DACs were "better", other than finding a spec sheet for the chips and comparing the ratings (bandwidth, SNR, bit depth, stuff like that).

Yeah, that sounds like the ticket. I can spend a little time doin' that.

I think you'll probably find that a lot of "skilled pros" don't necessarily know a whole lot more than the "average joe" about computer-oriented stuff like this (at least if their background is in home theater/stereo equipment).

Yeah, there's truth to that, but there are educated pros out there (David Ranada comes to mind, et al.) who have formal educations in audio engineering or related fields and many years of experience writing for well-respected audio publications. There are a few handfuls of guys out there who are the real deal. The trick, of course, is like you say -- finding folks who can, and do, apply their audio knowledge to computer-oriented stuff like, well, sound cards and their DACs. That's what I'd really like to see, but I haven't seen much of such things yet. So I'm stuck relying on Average Joe's opinions on sound cards, without knowing Joe's credentials behind his opinions. Having said that, I will check out that site you linked me to. Maybe there are some genuinely qualified reviewers or members over there.

Thanks again for the info and taking the time to educate me a bit.