This is neat! It's a software DSP that analyses a short, "impulse" response and from that can derive pretty much any combination of EQ, reverb etc and implement it in foobar's audio pipeline. The idea is that you take a reference impulse file (usually a white noise "blip") and apply your own effects to it - Convolver identifies these and applies them to whatever foobar is playing at the time. I've been messing around with it for a couple of hours this evening, using Cool Edit's parametric equaliser to process the impulse file. The blue plot is the native room response and the purple plot is with the DSP active. The difference in terms of real-world listening is remarkable. You can see I had an absolutely huge peak at ~64Hz which created that uncomfortable "pressure-in-the-ears feeling" on certain tracks (like sitting in the back of a car going at 80mph with just the front windows open, lol). Not perfect but it's a start and I'm sure I can get things +/-3dB without much more effort. A nice free upgrade for 2 channel HTPC output. MuFu. P.S. I think there's something similar available for Winamp as well.