Just discovered EqualizerAPO and WOW! I am using the flat curve (only one I could find) for my HE400 and I like the sound of the EQed cans much better than stock. I thought I would miss the bass and, to be fair, having head shaking bass is nice, but flat, the bass sounds so much less intrusive but still plenty present. I guess I just prefer a flat headphones frequency response. Who would have thought? Anybody else discover the beauty that is uncolored sound?