/r/audiophile Quality audio reproduction of all forms.
/r/headphones All topics related to headphones
/r/audioengineering Recording, editing, and producing
/r/AVexchange Trading used gear
/r/hometheater IMAX in your house
/r/vintageaudio Old School Cool audio
/r/diytubes Discussion of vacuum tubes and their uses
/r/diyaudioswap Have parts, skills, or projects that you'd like to sell or trade?
/r/diyaudio The subreddit this sub is replacing, check out /r/diyaudio for older posts though if you want to see some cool builds, otherwise /r/diysound is the right place for diy speakers etc
/r/audiophilemusic Music for your system and your ears
/r/budgetaudiophile Affordable stuff you can't build
/r/vinylpro and /r/vinyl for turntables and shellac spinnery
/r/headphonemods for headphone DIY
/r/synthDIY for all your DIY robot tone needs

Rules

Check out our sister subs /r/diytubes for vacuum tubes and /r/headphonemods for headphone DIY!