Bests & Worsts Reviews from Amazon

I really liked the idea of this sound machine. I use sound machines for sleeping and when I study so I purchased this one for travel. I have had it for a couple of days and I have started to notice this really weird high pitch melody coming from the machine. It happens every couple of seconds. I kept turning the machine on and off to make sure it wasn't something else. Definitely the sound machine. Once you hear it, you can't un-hear and it is very distracting. Sadly, this will be returned.