It's in my sig. PWD > S7.
Extension isn't the problem that bothers me, it's resolution and texture. The three different HE500s I've heard lacks it against most every ToTL phone I've heard on every system I've heard including BA, Mjolnir, Dynahi, BHA-1, Woo, NAD M51, Eximus DP1, etc, etc. Listen to a HE400 (a good one, I guess there are two variations) side by side and you should be able to pick out more information in the low end. Other than that it's just a monotonous droning type of timbre my ears hear. Other than that the HE500 is pretty good but I can't get over that part.