Using the vanilla 3.6-rc5 kernel with my Debian Wheezy system, sound is distorted: One can still recognize the sound that's supposed to be played in the distortion though. Unfortunately I don't know how to properly describe what I hear in English, please let me know if a recording would be helpful.
I am using PulseAudio as sound system. The distortion happens both with KDE system sounds and when using VLC.
Using the 3.2 kernel from Debian or a self-compiled vanilla 3.5.3 (and all the same userspace), sound playback is crystal clear, so this is a regression in 3.6. I can do a bisect, but I'd appreciate if someone could tell me to which directory it should be restricted - reporting this against the sound drivers is just a pure guess.

All this is on an Asus X53SM. The relevant part of the lspci -v output is:

00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
        Subsystem: ASUSTeK Computer Inc. Device 1ac3
        Flags: bus master, fast devsel, latency 0, IRQ 49
        Memory at df000000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [50] Power Management version 2
        Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+
        Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
        Capabilities: [100] Virtual Channel
        Capabilities: [130] Root Complex Link
        Kernel driver in use: snd_hda_intel