Windows 7's resampling sucks, How can it be improved? Options

[googlebot]

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 here. 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?

This post has been edited by googlebot: Feb 9 2011, 20:33

[SebastianG]

I also don't think -1 dB at 17 kHz and -3 dB at 18.25 kHz makes a difference in real listening situations. The early and slow rolloff has also advantages in theory (possibly lower delay, computationally cheaper).

[Notat]

I also don't think -1 dB at 17 kHz and -3 dB at 18.25 kHz makes a difference in real listening situations. The early and slow rolloff has also advantages in theory (possibly lower delay, computationally cheaper).

Such anti-aliasing filtering is necessary in a sample-rate and digital-to-analog conversion. As Sebastian indicates, there are trade offs in filter design. You are comparing Microsoft's software filter to the hardware filter in the DAC. They are implemented differently and it is not surprising that you can measure and hear a difference. Have you done any measurements on XP to confirm that there's a regression in Win 7. I would not assume that removal of user settings implies reduced performance. It could alternatively mean that overall performance was improved to the extent that user settings are no longer necessary.

[Woodinville]

Have you done any measurements on XP to confirm that there's a regression in Win 7.

XP and Vista (and I believe W7) are so dissimilar that there is no means to compare them. One is fixed, one is float, one uses a polynomial resampler, the other a dedicated, high-quality resampler (unless you provide many, many inputs in which case it will drop the quality due to the demand on the CPU).

That is, if you use new, rather than legacy, system inputs.

This post has been edited by Woodinville: Nov 5 2011, 08:33