(rec.audio.misc) Intended to be a catch-all for any any all posts that might not fit into one of the existing audio groups. Basically, anything that is audio-related and doesn't belong somewhere else is fair game.
Threads: 2,850 Posts: 14,637

(rec.audio.opinion) This forum is a place for users to post their opinions and experiences regarding home consumer audio.
Threads: 10,168 Posts: 165,498

(rec.audio.high-end) Within the realm of high-end audio, any topic is permitted. Theories, opinions, and questions are all appropriate if they are concerned with the reproduction of music.
Threads: 3,678 Posts: 35,752

(rec.audio.tech) A place for users to post concerning home consumer audio that are of a factual, practical, or theoretical nature. Sample topics might include: "How do I compute standing wave frequencies?" or "Ported vs. non-ported speaker designs"
Threads: 7,471 Posts: 79,147

(rec.audio.tubes) Discussion of vacuum tube audio equipment, including hi-fi, guitar (and other instrument) amplifiers, radio circuits, theory and design, vintage and modern equipment, repair/ modifications/ restoration and recommendations.
Threads: 9,772 Posts: 79,140

(rec.audio.car) Any discussion pertaining to car stereo systems in general, systems in cars, cars as they relate to stereo systems, car alarms, mobile navigation, car audio competition, and any other auto related sound topics.
Threads: 11,063 Posts: 51,657

(rec.audio.pro) A forum for the discussion of professional audio products, recording and studio engineering as it relates to any of following:- radio/tv audio for on-air and production, sound reinforcement & recording.
Threads: 36,406 Posts: 354,866

(rec.audio.marketplace) This forum is a place for users to post forsale and wanted articles of audio equipment that you wish to buy or sell. Note this is the *ONLY* place to advertise.
Threads: 16,840 Posts: 26,367

Any questions or feedback on what this forum is or how this forum operates.