rec.audio.high-end - join
High-end audio systems. (Moderated)
Low activity, 903 subscribers, Usenet

rec.audio.misc - join
Post about audio here if you can't post anywhere else.
Low activity, 232 subscribers, Usenet

rec.audio.tech - join
Theoretical, factual, and DIY topics in home audio.
Low activity, 1073 subscribers, Usenet