Muzak Holdings LLC, the company famous for bringing pop music into elevators, filed Tuesday for bankruptcy protection in a bid to restructure its crushing debt load.

Muzak, based in Fort Mill, S.C., filed for Chapter 11 protection in U.S. Bankruptcy Court in Wilmington, Del., along with more than a dozen affiliates, listing about $370 million in bond debt. The company also owes $105 million to its senior lenders.

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