I have an M-Audio FireWire 410 FireWire external digital audio interface and it has no noise as far as I can hear. The quality is outstanding and it is capable of supporting multichannel playback. M-Audio recently released the less expensive FireWire Audiophile which I would prefer over the USB Audiophile interface. Even with USB 2.0, I am not excited about the bus technology in terms of avoiding resource conflicts. FireWire, in my opinion, is a more media-friendly bus for handling bandwidth-intensive I/O. You might be better off going with the FireWire Audiophile as it also draws power from a wall wart power supply rather than through the bus connection like the M-Audio Sonica. Sometimes drawing power through the data bus can be a resource problem. Let the data bus be a data bus.
Now just to address the internal vs. external argument, I would say that there are many who are misled to believe that an external audio interface is better than an internal simply because it sits outside of a PC chassis. True, the PC chassis interior can be a noisy environment, but some high quality PCI-based cards have been rigorously evaluated against external audio interfaces and have been judged to be superior to some external DACs. It all comes down to circuit design and layout, quality of the components used in the circuits and the quality of the PC itself including power supply unit, motherboard design and quality, etc. Craig Anderton, a highly esteemed audio engineer and editor for EQ Magazine changed his views toward PCI soundcard audio interfaces when he came across the Lynx Studio Technology PCI soundcards.
