I have a number of USB audio adaptors that I am tried to get working with an Atheros AR9331 chipset router board. Every version I compile (tried historic and latest builds) has playback and recording issues. When playing back audio files (with alsa aplay) every other audio instance has what sounds like static or noise over it. When recording (with alsa arecord or sox rec) there is static and echo in the recording.
I then built the exact same OpenWRT build (recompiled) for an ipq40xx platform router board and used the exact same alsa settings and the playback and record is perfect! Does anybody have any idea why this might be? Why would it make a difference which platform it was built for and how can I replicate whatever (kernel or alsa) configuration works for the ipq40xx on the ar71xx?