This app sells the tracks very expensive. As much as 12.95 for the isochronic tracks, but they lack the ability to control the music or ambient noise and their separate volumes. Something that pretty much all other apps do. They give you the ability to listen to the music or ambient sound of your choice, or to nothing at all other than the tone or beat by itself. Wow, what a concept! Almost all the tracks Ive downloaded have music or ambient sounds that are downright annoying. The developer must think that everyone has her/his taste. May be that works for rookies but not for seasoned isochronic tone and binaural beats user like me. I have years using them. If I was paying .99 cents for each track then I would probably be OK, but when Im paying 13 bucks per track and I dont have the ability to get rid of the annoying music or ambient sound, its not worth the money. What is the point of listening to something that its not to your taste? Just because you pay a lot of cash for something doesnt mean that its high quality. Like they say, "not everything that shines is gold!" I have a feeling that this app is nothing more but fools gold. Hey developer, if you are going to charge a ridiculous amount of money for tracks, at least have some decency and earn your money by giving people the ability to play their own music or ambient noise or neither, and having the ability to control separate volumes. You have one of the most expensive apps in the App Store, yet it lacks very BASIC functions for an app of this type. You are not selling CDs at a book store, but an app.