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[Lynn]

Hi Matt,

What output mode (Wave, DirectSound, ASIO) will provide the best sound quality when using the PC as a front end to an external DAC and a Hifi?

I have heard that Directsound may not be the best choice since it may modify the sound in what I have heard is called kmixer.  

On the other hand, I have tried ASIO, which I understood provides a more direct route to the hardware.  However, it appears to be more timing sensitive even when one uses a powerful CPU and a dedicated music platform.  I recently did a comparision of ASIO vs. Wave, and I am not sure but in my setup it appears there is a loss of information using ASIO (background harmonics, especially on fast tempo songs are truncated).

Lastly, Waveout in the past bypassed Kmixer.  Is Waveout the way to go?

Thanks in advance to the inside developers scoop on the best path to use.

Regards,
Lynn

[Omni]

Lastly, Waveout in the past bypassed Kmixer.

Who on earth told you that?  Tsk. Tsk.  So sad the misinformation that gets passed around on the internet.  It's DirectSound that bypasses kmixer, not the waveOut API.

Check out this link (from the source!), and happy reading.

Omni

[NanjingGuy]

Who on earth told you that?  Tsk. Tsk.  So sad the misinformation that gets passed around on the internet.  It's DirectSound that bypasses kmixer, not the waveOut API.

Check out this link (from the source!), and happy reading.

Omni

The way I read their doc, not much bypasses kmixer.

At the top left of the figure, a DirectSound application loads wave data from a file to a sound buffer that the user-mode DirectSound system component (dsound.dll) manages. This component sends a wave stream to a WaveCyclic or WavePci device, whose port and miniport drivers appear at the bottom left in the figure. If a hardware mixer pin is available on the device, the stream passes directly to the wave port driver, bypassing KMixer. Otherwise, the stream first passes through KMixer, which mixes it with any other simultaneously playing streams. KMixer outputs the mixed stream to the port driver.

As before, the miniport driver binds itself to the port driver to form the wave filter that represents the underlying audio rendering device. This device might play the stream through a set of speakers, for example.

Alternatively, the wave stream can be rendered by a USB audio device instead of a WaveCyclic or WavePci device. In this case, the stream cannot bypass KMixer; the USBAudio class system driver (not shown in figure) always passes the stream to KMixer

[Omni]

The way I read their doc, not much bypasses kmixer.

I should have been more verbose.  Sorry.    I meant that between DirectSound and waveOut, only DirectSound has the capability of bypassing kmixer whereas waveOut does not.

Omni

[jleerigby]

Lynn,

Can I suggest that it will be a lot easier to read this forum and a lot easier for you to attract the attention of the right people to answer your question if you use a more meaningful subject heading.  This for example:

'Which sound output mode is best to connect to external DAC?'

Most questions are technical and Matt's not the only one who can answer them.

[nameless]

Oh, come on now, don't be quixotic!    People will never stop using subject lines like "Hellllllllllllllllllppp!!!!!" and "Question" and "Problem with MC" and "Why is this?".  It drives me clinically insane, but hey, that's what people are for, right?  

[JimH]

I've changed the subject.

Lynn, you'll get great advice from lots of folks here.

[NanjingGuy]

I should have been more verbose.  Sorry.    I meant that between DirectSound and waveOut, only DirectSound has the capability of bypassing kmixer whereas waveOut does not.

Omni

How do I know if my soundcard has a 'hardware mixer pin'?

What benefit is there to having the stream bypass kmixer?

[Omni]

How do I know if my soundcard has a 'hardware mixer pin'?

Well, an application can find out by querying the IPin COM interface maybe.  How the user knows?  I don't know... check the device's datasheet?

For the record, this is a little out of my field of expertise, so anyone else please feel free to jump in.

What benefit is there to having the stream bypass kmixer?

That is sort of a question that has both an objective and subjective answer.

Lynn, the original author of this thread who has seemingly disappeared, would probably want to bypass it since the stream could then be processed by "higher-end" equipment rather than by Microsoft.

Also, I have "heard" (though I haven't found a direct source to verify it) that kmixer resamples everything to 48 kHz.  I am highly skeptical of this, actually, but if someone dug up a link on Microsoft's site that confirmed this rumor, I wouldn't be surprised.

Omni

[phelt]

There are a number of frighteningly knowledgable folks over at Hydrogen Audio, and kmixer has shown up in quite a few discussions.

Here's a search of some of their forums for "kmixer"

Other, more refined searches of Hydrogen Audio might produce better and/or more specific results.

[slikvik]

kmixer does resample to 48khz which can be proved by trying to play 44.1khz DTS audio disc.

ASIO will bypass the kmixer, but I agree with the original poster that on my system (Denon 3802 and Rogers speakers) ASIO does tend to have more background noise when output to my Amp for DAC duties - cant explain it though.

Also worth noting is that most sound cards will resample to 48khz as well. This includes most SoundBlasters, most AC97 compliant cards and nForce2 Soundstorm. That last ones a real bugger for me as I bought that motherboard for Dolby Digital encoding features and then found out that nVidia kept in the resampling to make it more compliant!!

Vic

[jleerigby]

kmixer does resample to 48khz which can be proved by trying to play 44.1khz DTS audio disc.

ASIO will bypass the kmixer, but I agree with the original poster that on my system (Denon 3802 and Rogers speakers) ASIO does tend to have more background noise when output to my Amp for DAC duties - cant explain it though.

Also worth noting is that most sound cards will resample to 48khz as well. This includes most SoundBlasters, most AC97 compliant cards and nForce2 Soundstorm. That last ones a real bugger for me as I bought that motherboard for Dolby Digital encoding features and then found out that nVidia kept in the resampling to make it more compliant!!

Vic

I have a Denon 3802 and an Audigy 2.  This resamples at 96khz and sounds great using Wave Out or Direct Sound.  I can't tell any difference between the 2.