Medicine for the Soul

Also known as music. How is it possible for random sounds in melodies to be soothing to one's soul when feeling down and out? After all, its just random sounds which sound good to the human ear. One might initially assume that it's just the lyrics that soothe, bringing up good and constructive memories which help heighten the mood. Sure, this might be a big part of it, but what about music without lyrics?

I know first hand that music without lyrics can work just as well as music with lyrics in calming the spirit down. There's the tempo, rhythm, and melody which can be attributed for, but this doesn't really explain anything. I'm at a loss for how this whole music soothing thing actually works :-/ . One thing is for sure, it does (I speak only for myself).