T here Are a Lot of Metamusic Tapes. The Hemi-Sync sounds that are blended into the music are the same or similar in most Metamusic tapes. The biggest difference is the music itself. Metamusic tapes are designed to be played in the background, so you won't find strong melodies and rhythms that would ask you to pay attention. Differences lie mostly in the instruments used and the general melody of each piece.
Music preferences are highly individual.
If a tape is used at home or in therapy over open speakers, it is very important for everyone listening to like the tape. Hemi-Sync doesn't make the brain respond in a specific way just because of the sounds. It invites the brain to participate. If you sense that it's not okay, don't use it. If at all possible, borrow a tape or listen to a music sampler tape before buying a tape.