Frédéric Giasson has published a new version of the Music Ontology (revision 1.11). One of the discussion on the mailing list was the taxonomy used for musical instruments (both classic and not). The current musical ontology leaves this open, the users can refer to their own taxonomy.
At the time of the discussion I made a conversion of a taxonomy on MusicBrainz (I hope to have used most up-to-date version). I converted it into SKOS, which seems to be the most appropriate format for something like that. I created a purl URI today; ie, here is a stable namespace for it:
Of course, any update request is welcome…
Rectification, 2007-04-06: we agreed with Frédéric that it would be better to use another namespace for the taxonomy that would be closer to the music ontology itself. The final namespace for the taxonomy is therefore: