Q: Is USB the best-sounding PC output available?
A: No. In my tests, FireWire proved to be a far better audio interface than USB. As already noted, FireWire PC ports, though not universal, are commonplace. However, there is as yet no such thing as a FireWire DAC. So in order to assess FireWire, I turned to the pro recording market, where FireWire is the PC audio interface of choice. There, a large array of FireWire gear is available. Because many of these units incorporate S/PDIF outputs, they require nothing special on the DAC end. Many support resolution of 96/24 or higher.
I tested one example, the Focusrite Saffire ($499), and was knocked out not only by its lovely sound, but by the complete absence of the characteristics that spoil USB. (My review of the Focusrite Saffire, referenced above, contains a detailed description of the Saffire’s and FireWire’s sound.). While the Saffire alone cannot speak to FireWire’s ultimate sonic potential, it does establish a floor that is already higher than USB’s apparent ceiling. This interface holds great promise for audiophiles.
USB heralds a new era in the way we buy, store, and play music, but for now it is sonically a step behind. Coax S/PDIF is unquestionably a superior digital interface, capable of a natural presentation, rhythmic engagement, and tonal richness that elude USB. Given that S/PDIF is by far the more entrenched source-component interface—a state of affairs that hopefully will not drift wayward—most audiophiles need not worry about USB’s current limitations.
Yet the idea of a laptop acting as a music server has real merit, and here coax S/PDIF is rarely an option. Instead, the two most common interfaces are USB and FireWire. Here again, though, the existence of good-sounding USB-to-S/PDIF converters reduces the need for a USB DAC. Meanwhile, it has long been accepted dogma in the pro recording industry that FireWire sounds better than USB. My own tests, in a completely different context, confirm that consensus. Given that, high-end designers would do their customers a great service by producing a FireWire DAC. No doubt audiophiles would also welcome a FireWire-to-S/PDIF converter built to audiophile standards. The sonic possibilities of such products are truly exhilarating.
Despite the presence of alternatives and workarounds, the USB revolution will undoubtedly continue to build momentum, fueled by the interface’s ubiquity and simplicity. Considering the currently deficient state of USB audio, the high end must not merely embrace this revolution, but direct it toward the sonically meaningful standards our industry is built on.