Creative Commons license Attribution-NonCommercial-ShareAlike 3.0.

It allows sharing (copy and redistribute) and adapting (remix, transform and building upon) the material (music), in any medium or format under three conditions: Attribution (name and link to the creator and license), NonCommercial (no revenue must be gained from sharing or adapting) and ShareAlike (if you build upon the work, you must re-distribute it under the same license).