The HF roll-off is a result of low-passing twice, first by DirectSound and then again due to the bug.
Why should DirectSound do 20kHz lowpass-filtering if you're using 192kHz sample rate on the output?
Your signal will imho be lowpass-filtered twice, once in the output stage at around 40-50kHz (if your codec is good) and once in the input stage at 20kHz (recording at 44.1kHz).
Maybe we can get an additional confirmation? Personally, I would also scratch my head if I read this. The culprit is an ALC889 on an Intel DP55WG mobo.
Full stop. It was just RMAA that fucked up. And with it I did ofc. I should not have relied on a single tool. When I playback and capture white noise manually wit Audacity, everything works as expected at all sample rates, including 192 kHz. There is no 20 kHz low-passing at 192 kHz. It is just RMAA that behaves strangely at 192 kHz with the ALC889. At 96 kHz and below it measures full-spectrum. Set to output 192 kHz in non-loop-back mode it falls back to just 20 kHz bandwidth. But in loop-back mode it tests the whole 96 kHz bandwidth. Next I will try to reproduce the HF roll-off manually with Audacity. Maybe that was also just RMAA.PS I also cannot reproduce the 44.1->192kHz roll-off with Audacity.For the record: Windows 7's resampling is fine!
I couldn't longer ignore the impression that the resampled output sounded somewhat muffled and did some measurements.
What about your initial suspicion about muffled sound?
http://blogs.msdn.com/b/matthew_van_eerde/...-pull-mode.aspxhttp://blogs.msdn.com/b/matthew_van_eerde/...t-you-hear.aspxIs it possible to test Vista/Win7 SRC quality with this small app? If yes, then 192->44.1kHz or 44.1->192kHz SRC isn't that bad...
How exactly was this Adobe Audition plot made?
What was the source sweep file derived from?
What Play and Record applications were used?
Quote from: Greg on 17 April, 2011, 03:51:11 AMHow exactly was this Adobe Audition plot made?Select the whole audio, press Alt+Z, press "Scan Selection".Quote from: Greg on 17 April, 2011, 03:51:11 AMWhat was the source sweep file derived from?IIRC it was just a pulse train.Quote from: Greg on 17 April, 2011, 03:51:11 AMWhat Play and Record applications were used?Play: silence.exe + foobar2000 with DirectSound output.Record: loopback-capture.exe
Playback over WASAPI must match the sample rate of the output device. Thus applications must supply their own resampling if the playback rate does not match. Most applications don't do this but just employ MME or DirectSound, which provide transparent resampling for non-matching rates.Since some of my content is 44.1 kHz and some 48 kHz I used to set the output rate to 192 kHz so that all audio had to be upsampled. With good software resampling and a cheap onboard codec this could, in theory, even improve the overall result. But the opposite was true. Today I couldn't longer ignore the impression that the resampled output sounded somewhat muffled and did some measurements.You can view the result [a href='index.php?showtopic=86675']here[/a]. The upsampled output (44.1 -> 192 kHz) suffers from quite a HF roll-off in comparison to pure 44.1 kHz output.In Windows XP the SRC quality could be adjusted. I can't find anything comparable in Windows 7. Does anyone know more?
Media Foundation, DirectShow, DirectSound, and waveOut each do sample rate conversion slightly differently. There is a bug in the waveOut sample rate conversion which results in a lower-quality sample rate conversion than was done in XP.
Have you done any measurements on XP to confirm that there's a regression in Win 7.
Media Foundation, DirectShow, DirectSound, and waveOut each do sample rate conversion slightly differently.
I generated a 40 Hz tone in Cool Edit Pro, both in 44.1 kHz and 48 kHz. Whenever the sample rate doesn’t match the Windows sample rate, I hear the same high-frequency distortion artifact.Here are the results of playing a 44.1 kHz WAV file (40 Hz tone) in various apps with the Windows sample rate set to 48 kHz:Cool Edit Pro 2.0 – distortionWindows Media Player – no distortionFoobar2000 – no distortioniTunes 7 – no distortionWinamp (with Directsound output) – no distortionWinamp (WaveOut output) – distortionIn short, Directsound output upsamples correctly. WaveOut produces distortion.