ALSA (or "Advanced Linux Sound Architecture") is the preferred framework for doing low-level sound on Linux systems.
The ALSA API was introduced into the LSB as a trial-use module in 3.2.
The plan is for ALSA to become a required module in 4.0. Two things are needed before this can happen:
Is it useful? Can apps use it? One high-visibility app to check: OpenJDK (see LsbJava.
As a complication, the current spec is what it is because of the state of ALSA in SLES 10 and RHEL 5; if we stick to our plan to tie 4.0 to the current enterprise distros, we can't add much.
We need tests. Currently, ALSA has no tests at all apart from the generic checkers. A suite is being developed (see Template2Code), but its release date has not been set.