Is there an ACPI script or something?

Seems to occur only after the latest update.. Seems to disable ALSA after 11 seconds without sound and makes a loud cap-POP!! when sound starts again, i don't think that's worth what power it conserves so rather let it just stay on.

This is probably controllable/settable using either the sysctl method (setting states by echoing commands into /sys/somewhere) or by using a module option in /etc/modprobe.d/alsa.conf or a similar file either pre-existing or of your own creation.

Either method depends mostly on what particular audio device (what sound chip) you are using, and which driver module, and also, it may help to tell us which Linux you are using (is it the SuSE Linux? You appear to have posted from a Solaris machine.).

If you know what sound driver you are using, you can query it for options that it accepts; as an example, if you have a sound chip that uses the snd_hda_intel driver (the Intel HDA driver) you would try:
and in the output, examine the lines beginning with "parm:" as these are "parameters" that the driver accepts. Maybe there's a power_save parameter (the snd_hda_intel module apparently does have such an option) which you could set to "0" for no power saving, or "10" for max power saving.

Sasha