[sardon]

One thing which I've done and which has worked somehow, is to give it away to artists out there.

Make a list of artists (musicians in your case) which you think would like your app. Do some serious research to some contact detail for them. You then write to them and offer them the app for free, through a coupon code. Ask them for feedback. Write casually, like the indie dev that you are.

If they like your app, it's likely they will talk about it, and generate some buzz, which hopefully some blogs / sites will pick on.

And be ambitious with the artist list, send it to top people !!