http://bugs.winehq.org/show_bug.cgi?id=14717
--- Comment #90 from Alexander E. Patrakov patrakov@gmail.com 2010-12-27 23:49:59 CST --- (In reply to comment #87)
it is meaningless to test those emulated sound card sb16 and ac97 in kvm or virtualbox.
I would agree if the emulated sound card used the driver specifically written for it (i.e., something analogous to the VMware video driver). However, the emulated card pretends to be a real thing, identical to something manufactured in real-world silicon, and uses the drivers meant to be used with the real-silicon cards (i.e., the drivers that come with Windows itself). So these drivers would send identical output to the emulated and real-world cards and thus are suitable for reverse-engineering the resampler, provided that kvm itself does no resampling (that's why QEMU_AUDIO_DAC_FIXED_SETTINGS=0).
The reason for using an emulator is that it allows to capture the output digitally. A real sound card with S/PDIF output would also work if I had something that could record from S/PDIF.