I work in this niche too and get 4k visitors a day - non-grey ways to monetize that I've found work successfully:
standard adsense / DFP: CPC is low but CTR is good, I average 1.5%+
affiliate links through to buy the music: half decent, but most people want illegal downloads
pre roll videos etc can bring some income, not loads though unless you have decent video delivery via a custom player
generally, I find just drive more traffic and keep it simple with adsense works for me, other ad networks just don't have enough advertisers to want the niche traffic, and often euro traffic.
one of my close associates is more focussed on doing releases and offering downloads of promos from artists, they get more traffic (10k+ a day) and took the move to set up their own ad network across that site and some download ones they have, it's worked well for them as they can get a much better rate for CPC/CPM, but also it takes 2 people a full time job to negotiate ads and keep on top of things.
