My tests over kmixer effects, Seem to be none... Options

[KikeG]

I've been doing some tests over kmixer effect, both using standard waveout and directsound, connecting my TBSC digital output to my Audiophile digital input, under WinXP (no SP1), and I'm sure that with a single stream at 48 KHz, with the TBSC mixer volume at max, the kmixer doesn't touch a bit of the audio stream, it's sent bit-perfectly to the output of the card. At 44.1 KHz I can't be so conclusive, since the TBSC resamples everything to 48 KHz and I've had some problems to test it the same way, but according to my analog measurements in loopback mode of Audiophile output, there is no trace of signal degradation over the 44.1 KHz played data.

...So it's very possible that this kmixer sounding worse than ASIO or k.streaming is our old friend mr. placebo entering into scene again.

Anyway, I'll do some more tests in the future.

This post has been edited by KikeG: Jan 16 2003, 09:42

[Patsoe]

There's some evidence that using directsound acceleration (also called hardware mixing) does same thing as using kernel streaming, and enables getting bit-perfect output. However, I haven't been able to verify this, since my Audiophile card doesn't support it.

I've tested hardware mixing today on a Terratec DMX 6fire 24/96 and can't confirm this evidence.

I used foobar2000 v0.667 for playback and CEP2.00 for recording; OS is Win2k SP3, Terratec driver version is 5.00.2000.128.

Setting kernel streaming in foobar, recording in digital loopback was bit perfect. So, I concluded CEP was fine as a recording interface.

Then I selected Directsound, and ticked 'Allow hardware mixing'. In Windows Sound&Multimedia Settings, there's a Hardware Acceleration slider. I tried all settings. In the higher two, foobar reports 'Hardware mixing available, 33 streams total'. In the lower two foobar says 'Hardware mixing not available'. In both cases, loopback was not bit-perfect: spectrally flat 1-bit dithering was present (and dithering in foobar was disabled, as were all dsp's, ofcourse).

I found the same using Waveout.