I have been playing classical music specifically and routinely to my plants for the last 3 years and apart from making me calmer, I swear my plants have been healthier too. It has been suggested for decades about plants and classical music being beneficial and whereby heavy rock/metal can actually kill plants. After careful observation of my plants and a perceived increase in over all well being, I now try and make sure that they get 3-6 hours a day of classical music and feel that if I don't play it for more than 2 days in a row, they somehow seem to be "asking" me or "telling" me that they are unhappy that they haven't had their "music therapy" and would I please put the radio onto the classical music station for them. It is probably all in my head, but I do reckon I can notice a difference in my plants and will forever more, use this "music therapy" as an integral part of my growing technique.
I must admit to being a "bit out there" though, as I am also a firm believer in "companion planting" and using the lunar cycle to influence my decision making regarding all aspects of cultivation. None of these things are harmful and probably a bit "esoteric" for most people, but perhaps used in conjunction with each other, they can actually lead to happier and healthier plants. Either way, I am now an advocate in all 3 of these principles and will continue to make them an important part of my cultivation strategy and also believe my plants have never been healthier since I began using all 3 ideologies together, with dedication.
Hope this helps,....
Organoman.