Well, simply put, any music that YOU find soothing (we’re talking soothing, not your favourite party selection). There has been much written about different musical styles and origins, and it is true that specific tempos and rhythm play a definite role – but all this is of no benefit if you simply do not enjoy the music you are listening to. In fact, it can have exactly the opposite effect that you’re hoping for. If you don’t enjoy classical, it’s okay. There are many modern composers producing work that you’ll likely enjoy.