It is true dogs hear things much "louder" than we do so volume is important in the relaxing effect of music on dogs.
Dogs seem to relax to soft slow strains, and sometimes become agitated to loud, drum-based tunes. Queen's University in Belfast, Northern Ireland, and the Rehoming Centre of the National Canine Defence League in Evesham, England studied the effects of music on dogs and found this to be true. Guide Dogs for the Blind training facilities tested music specifically composed by Thomas Schoenberger to calm pets. They were sufficiently impressed to endorse the CD called Doggone Songs for use in stressful situations such as separation anxiety, injury recovery, storms, fireworks, travel, destructive behavior and aggression. This CD is also touted as an aid in training. Considering that music helps memory, and stress reduction helps learning, it makes sense. Another album created specifically for dogs is called Ask the Animals: Songs to Make Dogs Happy! by Skip Haynes. Some song titles include "I'll Be Back," and "I Love Food," two proclamations that most dogs love to hear.
Many animal behaviorists, veterinarians, kennel keepers and even pet owners now play music for their animals. Just one of several ways to deal with anxiety, the right kind of music can reduce stress, aid relaxation and alleviate depression. The shelter where I volunteer leaves a radio turned on low in the dog room at night. It provides background sound to soothe their sleep. Sleep is important to overall health and serves to keep barking to a minimum.
Music can have an even greater beneficial effect on dogs if they associate certain tunes with a positive experience such as cuddling on the couch with their humans or enjoying a gentle massage. This can be another tool in easing your dog's stress if he suffers from separation anxiety.
While You Are Gone Music Pets Love: http://www.amazon.com/gp/product/B00004ZB78?ie=UTF8&tag=k9co-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=B00004ZB78a link to a one of the music CD's made for dogs