- Wiki: Public_domain_music. Musopen does the hard work.
- Quora: Can you use music by long dead composers like Mozart, Wagner or Strauss in a film or advertisement without paying royalty fees? If so, is there a database or resource for specific recordings?. Short answer - Yes.
- Filter by author, performer, instrument.
- Easy to find with search, filter and order.
- Comfortable interface - has preview, filter by the perfomer and clear info about the current audio's copyrights.