The AirPort Express wireless router can stream multichannel audio out of its hidden S/PDIF jack. Just add an -inch-to-Toslink adapter.

The palm-size AirPort Express ($99) by Apple (apple.com) has some surprising abilities. Connect an Ethernet cable, and you can create a 10-user Wi-Fi network. Connect a USB printer, and you can print wirelessly. Or connect a stereo miniphone cable, and you can play audio from any Wi-Fi-enabled Mac or Windows computer running iTunes. You can even stream audio to multiple AirPort Expresses.

At the bottom of the audio jack, though, lurks the coolest musical feature of all: an LED that beams out a lossless, optical S/PDIF version of the audio. Drag a DTS or Dolby Digital file into iTunes, and the AirPort Express can transmit the multichannel signal to a surround-sound decoder. The secret is to crank iTunes' volume to its maximum and turn off all audio processing (EQ, Sound Enhancer, Sound Check, and so on). With Airfoil ($25) by Rogue Amoeba (rogueamoeba.com), you can stream audio from other programs, too. (For more about David Battino's work, visit batmosphere.com.)