"Sobald die Glocke hier erklingt, Die Marke aus dem Kasten springt."

If only musical, how about
  "When the bell sounds, the melody jumps out of the box."

Or if it's advertising, possibly
  "When the bell sounds, the brand name jumps out of the box."

Or better yet, "When the bell sounds, the beat jumps out of the box."

It's (perhaps obviously) years since I learned German ...

Todd Augsburger - Roller Organs
http://www.bright.net/~allmax/index.htm