Short and sweet to start. I'll add more later... Backstory From the first listen to the HE-6 I immediately thought there was something off about them. Some claimed they needed break in, others claimed to try various pads (which did help to some extent). However there was always treble glare and just a overall brightness to the sound. I could tell there was potential even compared to my fully modded HE-500. The bass was more refined and had articulation and differentiation between notes. Definitely NOT one not bass! I started playing around with different materials to try and tame the treble and etch that I was hearing. I was going all by ear and wanted to match the gold standard reference the HD650. Frequency response of my mods done by ear I was pretty happy with these mods as I was trying to reach a -10dB slope target from 20Hz to 20kHz. However, there are inconsistencies like the 1.3kHz peak, the dip in the midrange, and the slight treble bump at 8kHz. I decided to build a measurement rig to get accurate and repeatable results. HD650 for reference My current mods for HE-6 Here is an overlay of HE-6 modded vs HD650 HE-6 with Audeze pads and no grills (this is soooo close to sounding right) I'll post pictures of my measurement rig later.