A classic rock station here is the first radio station to broadcast in stereo-compatible MPEG surround on its main digital HD-Radio channel, but it's not the first U.S. radio station to broadcast in surround.

Boston's WZLX-FM began broadcasting select songs this week in 5.1-channel MPEG Surround over its HD-Radio signal to prototype receivers provided by the Fraunhofer Institute to Bose, Boston Acoustics and Tivoli for evaluation. MPEG Surround delivers surround sound through a multispeaker audio system but also creates virtual surround through a pair of speakers, according to Coding Technologies.

Prior to that launch, 61 classical FM stations in stereo-compatible 5.1-channel Neural-THX Surround over the air and over the Web. (See story above.) The broadcasts can be decoded by commercially available home A/V receivers incorporating the Neural decoder.

Boston Acoustic confirmed that it has an evaluation unit but said it has no current plans to develop such a product at this time.