Royalty Free Music is NOT Royalty Free!! Say what?
Usually Royalty Free Music licensing does not include “public performance” royalties. Those are royalties paid to composers when their music is performed publicly – on television for example. But these royalties are not being paid by you (the music purchaser) they are being paid by the network that is broadcasting the show where the music is performed either as a featured piece or more commonly on television as background music. Performing Rights Organizations (PRO) like ASCAP, BMI, SESAC, SOCAN, PRS, etc. are being paid by the networks and are in charge of distributing the performing royalties to the music composers. So for the person purchasing the music license it is entirely Royalty Free but if fact some royalties may be paid to the composers by the PROs. Wikipedia mentions this as well on its Royalty Free Music page.