While it may not look like much, what's contained in those little black boxes is the future of hi-fi: USB audio done right. Empirical Audio has been on the cutting edge of USB audio design for a while now and they're even closer to the Holy Grail of playback with a few new goodies shown at Vegas and rumors of even more products to come.
First, Empirical's Steve Nugent is a man bent on destroying jitter. For those out of the loop, jitter is what makes CDs sound nasty. We covered an excellent article by Steve that is a must read for anyone remotely interested in the CD/USB/vinyl wars taking place and why, ultimately, USB will win. If you're unfamiliar with Empirical, they're a modding house hot-rodding all kinds of DACs, preamps, amps and other gear in addition to their line of USB converters. If you have any question about this guy's mad skills, check out the reviews at the Audio Circle forum.
Now, as a means to reduce jitter even further, Steve champions I2S connections on his USB converters. I2S is, according the Empirical literature, "the native interface on most DAC chips." By running I2s straight to the DAC, S/PDIF conversion and associated jitter is tamed. Of course, you have to have a I2S DAC such as the great Perpetual Technologies P-3A or a Benchmark modded by Empirical, both of which are available from Empirical. Yeah, it's a barrier to entry, but I love seeing someone throw convention to the wind and say, "hey, this new connection is technically superior and just sounds better...hello, is this thing on?"
Price for the Freeway USB I2S is $550 while the higher end Off-Ramp is $950. You can, of course, purchase his USB converters with standard S/PDIF outputs. Rumor has it a wi-fi model is in the works based on the Apple Airport Express. Additionally, Steve, having cracked apart enough DACs and tweaked them into perfection, believes he can bring out a USB DAC of his own design that will blow this industry wide open. Keep an eye out for this guy, he's a man on a mission.