Samsung Electronics said on Wednesday its unit Harman International signed a deal to acquire U.S. firm Masimo's audio business for $350 million.

Now, in a move that many suspected might come sooner, Masimo is unwinding that decision—announcing the sale of Sound United to HARMAN International (a Samsung subsidiary) for $350 million in cash.

This move supercharges Samsung's ambitions in the premium audio space. Harman already owns a stable of respected audio brands, including JBL, Harman Kardon, AKG, Arcam, Mark