Try one of these services to take your soundtrack from so-so to supersonic:1. Audio Sushi (audiosushi.com) taps its library of 3 million-plus tunes to create brand-appropriate music, and even suggests hip but mellow songs.2. Custom Channels (customchannels.net) delivers its edited playlists through an online radio station built expressly for each client.3. Rockbot (rockbot.com), the first music app built specifically for businesses, lets retailers create and stream playlists; customers vote on and request songs from their phones.4. Prescriptive Music (prescriptivemusic.com) curates programming online and makes private-label CDs. Virtual channels let users control sound zoning, beats per minute, and more. 5. Muzak (muzak.com) builds custom channels for businesses and sells subscriptions to its proprietary background music channels.