http://www.gentoo.org/doc/en/alsa-guide.xml has references to alsaconf but alsaconf is no longer installed since it's broken with sys-apps/kmod's depmod and was useful only for old ISA cards Users should be editing /etc/modprobe.d/alsa.conf directly, or do nothing at all since udev autoloads the modules by default just fine Only when rc_coldplug= is set to YES in /etc/conf.d/udev the modules won't get autoloaded by udev
Looks like this is solved by the migration to https://wiki.gentoo.org/wiki/ALSA