I love listening to Tool w/ the HE-500. I'm actually listening to Lateralus (one of my favorite Tool albums) w/ the HE-500 as I type this (laptop >> Headstage DAC cable >> Objective2 amp >> HE-500).
It sounds fantastic. Things that impress me right away is the clarity, microdetail, control, timbre, and balance the HE-500 offers. It makes this equally vicious & elegant Tool album sound absolutely effortless. Notes have terrific weight and imaging is near perfect. Treble is very articulate, detailed, and accurate..while remaining smooth and non-fatiguing. The unique liquid-y midrange presentation is absolutely addictive.. if you've never heard a (properly amped) ortho, you have no idea what you're missing out on when it comes to the midrange presentation. It's truly one of a kind and makes going back to listening to anything else quite difficult. Bass is very well textured, nimble, precise, and extended very deep. It's balanced in it's presentation so there is no unnatural boost (or recession) in it's tuning. Decay and speed is perfect.
It's important to note that the HE-500 will take you as far (and as well) as you're will to effectively amp it. While not as voracious as the HE-6, don't let its seemingly manageable sensitivity specs fool you. It's likes power.. and lots of it. The Objective2 drives it surprisingly well, though (as does the fantastic Neco Soundlab V3-portable amp). If you want to hear just how textured, effortless, balanced & robust the HE-500 can sound, amp it well.
As I've said before.. the HE-500 is one of the best investments I've made.. in all of electronics & audio. I couldn't be happier with it's sound and it's actually saved me a bunch of money since I've got no desire to buy any other full sized phone.
Edited by FlySweep - 6/5/12 at 11:28pm