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Not to be curt...

Posted by Presto (A) on October 6, 2011 at 17:46:33

In Reply to: RE: What did you find objectionable in that review? posted by John Atkinson on October 6, 2011 at 10:01:50:

But it's a yes/no answer.

Did you guys use ASIO or not?

This is a dual-headed driver -> it functions under the WDM (Windows Driver Model) and ASIO. Personally, I avoid cards with C-media based chipsets and associated drivers like the plague. Recent codecs HAVE provided for non-resampled digital out and a greater variety of sample rates and this has found it's way to their cards. For example, the ASUS Xonar D2 that I tested had strange counter-intuitive ASIO channel mapping (at the time of testing) and also does NOT accomodate automatic sample rate detection.

But I digress - back to the issue at hand:

ASIO operation can be totally different from WDM operation, IME and withing WDM operation, waveout, kernel streaming, directsound and now the new WASAPI can all behave differently as well. This is especially true when it comes to things like volume controls and resampling. There are also certain things that people need to be aware of (that few understand completely) that need to be done in the Windows environment to ensure that bitperfect playback is obtained when using WDM. The lack of a clear and total understanding of how the various iterations of the windows audio stack actually behave (given complex condition sets) has led to a plethora of misinformation about when and how the stack resamples. Some said that the stack ALWAYS resamples to 48khz, and is on ALL THE TIME (even with one stream) and kernel streaming is the only way to get bitperfect playback. Wrong. I was able to get bitperfect out using directsound (out of windows media player actually!) through to a receiver using a DTS test track that will scramble not only with resampling but even due to a simple volume bit change! The DTS test (if it can be used) is truly definitive.

So back to the review in question. The fact ASIO4ALL "cured a problem" is not proof positive there was a problem at all. Huh? In other words: the fact that there was resmpling going on does not mean (necessarily) that the driver is inherently defective. It *could* just mean that on that particular PC with that particular OS/Service Pack/Settings and that particular player and those particular Windows Audio settings that the windows digital mixer was being envoked for SOME REASON. It could be as simple as a microphone input being "on" or a seemingly innocent application polling the WDM driver causing the resampling engine to be enabled. Resampling can be enabled without "hearing" something being mixed in as well, something that many people also miss. It can be a negligible noise floor - the point is that a second data stream is present - even if that data stream seems to contain "nothing", its' still "there", just like zeroes in a true digital (-inf db) silence still results in a data stream. It's streaming zeroes - but it's still streaming.

I don't doubt the reviewer had an issue with the card. It's just his explanation for the problem which is not, in my mind, adequately definitive. I've done EXHAUSTIVE tests of WDM drivers (Direct Sound, Waveout, Kernel streaming), ASIO4ALL and ASIO drivers using various audio interfaces and let me tell you - there are some seemingly innocent or innocuous variables and settings that can cause digital mixing to be invoked. Worse yet, 90% of "definitive intel" out there in cyberspace is a combination of data that is either incomplete, partially incorrect, correct only for a specific condition set(s), or just dead wrong.

I'd love to install this card and run it through one of my "bitperfect" test batteries and see if this condition can be emulated, then provide what would be a more concise explanation as to the source of the resampling in non-ASIO mode.

I'm not a fanboy of this card at all. I already stated that I returned to the store it's little brother (in other posts). My agenda here is really simple: we need to be careful not to create false corollary especially about resampling because this information spreads like wildfire in our surprisingly small little online world of computer audio.


I liked the review. But I think the resampling part requires further investigation (or at least further explanation). Maybe the test done was definitive. Or maybe it was not. Too little info to say one way or the other.

Cheers,
Presto

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