Mechanical sounds include showers, fans, cars, or anything else man-made. These are often more repetitive than nature sounds and can make a great background noise to get young children or babies put to bed. If you don't hear the sound right away please turn up your volume.
Choose a track and hit to listen to the relaxing sounds.
Wikipedia - White noise Babies Online FREE Birth Announcements - Create a web site for your new baby, complete with pictures, instantly and for free! Tons of other great (and free!) stuff for new and expectant parents too, so check it out. About.com - Get information on sleep disorders and how you can treat them.