Oh, you're listening to them stock? The HE-6. The headphone you shouldn't listen to in stock form. Err, well, that's what the internet would lead you to believe. Hop around HF and you'll find that it's very rare for someone to contently listen to these stock. One way or another, HE-6 owners take the extra effort to make sure their headphone is not as Hifiman intended. Anyone who's been on the Hifiman merry-go-round would find that the HE-6 has some odd dampening built straight into the headphone. And when I say "odd" I mean you won't find this on the HE-400, HE-500, HE-4, or HE-5-LE and certainly not on the new offerings from Hifiman. The dampening I am referring to is the fiberglass/cotton on the back of the driver and the triangular foam insert on the front (see OLD and NEW versions of earside dampening). Well, as you can imagine, just like the many other HE-6 owners out there, I don't want Hifiman shitting on my dreams and I figure it's time to say goodbye to the foam and cotton. For no reason other than "it's better". It doesn't really end there though. In fact, removing these is basically the 'default' modification. It's almost assumed, at this point, that nobody in their right mind would even bother keeping that junk in there. The real question, then, is with the pads. Hifiman has done a great job creating many different options in the pad department. When it comes to the pad rolling, the amount of options is enough to increase just about anyone's heart rate. I know my pets are certainly sick of hearing sine sweeps. So, without further adieu... Stole this sweet pic from HF Abbreviations used Pads: PL - stock pleather V - velour AV - angled velour (HE-400S pads) Fo - focus pad FoA - focusA 1540 - Shure 1540 Other: NG - no fiberglass/cotton NF - no foam on earside Rug - rug liner (same stuff used on Anax 2.0 mod) Subjectivity and stuff This is a bit of rapid fire. Feel free to skip this crap and get to the shiny graphs. Admittedly I went through these measurements fairly quickly and didn't have long listening sessions with each setup. I will comment where I felt a strong enough difference. Stock PL - Actually not bad. Bass and midrange is perfect, treble is a little rough in Sibilance City. tiny bit of wonkiness. Stock V - Brighter than PL. Upper mids and treble are a little glaring still, not bad. No wonkiness. NG PL - Wonky. Upper mids are not as present (despite measurements below). NG V - Very nice. Pleasant low bass and only a little glarey in the treble. Awesome mids. NG AV - Biggest difference from velour is bass is not as present. Maybe the bass decays more quickly here? Not sure since the measurments are very close. NG FoA/Fo - Similar criticism as the AV. Surprisingly, the FocusPads don't seem to have much of a difference vs. angled velour as opposed to on the HE-400S. NG 1540 - Just too dampened. These sound great on the spacey HE-4 but not here. Too intimate. Treble is way easier on the ears, however. NG NF V - Nailed it. I'm either getting used to the treble or this foam piece was somehow adding some glare. Nothing else seems affected, and the treble difference was subtle if possibly non existent -- not confident here. NG NF V Fuzz - Took too long to do the mod to notice big differences. This mod just makes sense, though. dampening reflected waves without impeding incoming waves? Sign me up. After doing some initial before/after with the glass, it was about the time where I said "screw it", thinking it gave an uncomfortable amount of glare. Plus, having more openness on the back sounded nice. Taking off the foam didn't change enough for me to try putting it back. Now for shiny graphs... Stock HE-6 (stock dampening, pleather pads) FR Distortion CSD Notes: Classic 1kHz PL peak. Effect of Removing Fiberglass (pleather) NG vs. Stock NG CSD Notes: Was not expecting the differences to be non-existent objectively. Velour (NG) V NG vs. Stock V NG CSD Notes: Cleaner CSD than stock, despite what may be the "ortho wall". Warmer tilt on the FR with a much more even midrange. Angled Velour (NG) AV NG vs. Stock AV NG CSD Notes: Even cleaner CSD than normal velour pads. Almost identical FR to velour. FocusAPad (NG) FoA NG vs. Stock FoA NG CSD Notes: More velour-like than pleather-like. Shure 1540 pad (NG) 1540 NG vs. Stock 1540 NG CSD Notes: The leveling of the treble is expected based on the thick pad dust cover.