A3D 2.0, one of the most popular positional audio API's, was designed to provide the best 3D audio experience using headphones. To the gamer, this means that Half-Life will sound even more realistic, the atmosphere in Thief will be enhanced, and you're going to have an extra edge when Quake 3 Arena is out with A3D 2.0 support. Seems compelling for the owner of a Vortex2 based card, but what about those who have something in the Live! family?

The benefits that accompany the Live! are a little different, but still very relevant. One of the main features of the Live! is the excellent sound quality and S/PDIF in for digital CD audio. Listening to a well-mastered CD on the HD 600s via the S/PDIF connection is a very pure experience, with sound quality even a seasoned audio enthusiast will appreciate. A set of speakers to rival the 600's will run you in the neighborhood of $1000/pair.

In order to get the most from the HD 600s you're going to have to make sure you have a nice PCI soundcard. Owners of legacy ISA cards should consider a sound card upgrade before considering these headphones.

If portability is an issue for you, then headphones are also the most likely alternative. Large speaker systems don't work well on the road, in an apartment, or in the study lounge (nothing like a good tune to keep you awake right?). Be warned, though, as these headphones require significant power to be properly driven, which can severely tax battery life.

So now that we have determined that headphones are a viable alternative to a set of speakers, lets take a look at the specs and explain what all of the confusing numbers really mean.

One of the most intimidating aspects of audio is taking a gander at spec sheets. While everyone is spouting off on video cards about fill rate and T&L, not many people really understand about impedance or harmonic distortion, which is why we're going to lay it down for you.