I will try to keep this a little more succinct that usual (key word try) and only include information relevant to the tuning correction on my Aeon. Please see my original thread for further information, but understand that any information in this thread supersedes my original impressions before the Aeon had its tuning corrected. I got my Aeons back a while ago with the tuning fix but have just now been able to post about it. I had anticipated a relatively minor change with the fix, but the Aeons sound noticeably different. As far as I know, this is what my pair was supposed to sound like. So, what has changed? - Much less low-end bass. They still have good extension but sound much more neutral now. This is both a pro and con in my mind. On the upside, they are more accurate now. On the downside, I liked that the extra bass pre-tuning-correction gave the Aeon some good "oomph" to the sound. I think this helps counteract what I perceive as a lack of macro-dynamics inherent in almost all planar headphones. (Even the lean HD800 can slam like crazy with the right amp. Not so much for planars, in my mind.) - Bass-to-midrange transition is much smoother now. No more major dips. There is still a bit of a disconnection, but it's more subtle and broad, somewhat like the Ether C with some filters in place. - Midrange and treble are both relatively unchanged. Now, what this means is that even though it's basically just the bass and lower-mids that have changed on the corrected unit, you would be surprised at how much of a difference this makes in the overall tone. The corrected tone is fairly neutral, but trends towards sounding a bit lean and bright. Previously, the upper-mids and treble sounded a bit bright, hard, and glaring on the Aeon. It was pretty easy to overlook with the excess bass. Now that the bass is relatively controlled, any upper-end problem areas stand out more. Everything is relative. - In continuation of the above point, the bass-to-mid transition no longer sounds hollow, but it still sounds lean and lacking in body (previously offset by the large bass boost). This also exacerbates any upper-end issues, and despite the overall neutral-ish tone, makes the headphone not feel as such. Despite sounding noticeably different, the overall traits from before the tuning fix remain. The sound is crisp, fast, and clear. Staging is fairly good for a closed headphone. They have decent resolution. It's really just the lower-end balance that came out differently. Without the foam inserts in place, I find the Aeons too lean, glaring, and bright sounding. They are more tolerable with the inserts. And, really, they are pretty balanced sounding in and of themselves, especially for a closed headphone. I know it's not easy to get everything nailed down perfectly. Given that, I do still think they are a good headphone and overall better now with the tuning fix than what I heard originally, but I recommend an audition before blind purchase. Using different front damping actually goes a long way on the Aeon. A bit of toilet paper, or similar material, and thicker foam can really do wonders for the Aeon. If you are very careful and have precise measuring gear to ensure channel balance, you could theoretically change the port damping material too. Just note that I don't think this is necessary, nor should you expect Dan or MrSpeakers as a whole to support that level of tweaking. Measurements The corrected Aeon is indeed quite different on the low-end. No more huge bass hump (required an absolutely perfect seal - slightest leak = goodbye bass). No more huge dip while transitioning into the mids. I would argue that while this is a very positive change overall, an even better subjective balance could be obtained were the bass to be a little heavier up until about 100Hz and with a slightly warmer-tilted blend into the midrange around 500Hz. Think more of a straight line from 10Hz to 500Hz. As it stands right now, everything between, say, 80Hz and 500Hz sounds to be lacking in body. And while that's a lesser issue than the pre-fix dip, I still find myself wishing for that next step in adjustment. Otherwise, the Aeons sound about the same as before in the rest of the midrange and treble. And while the overall response looks pretty decent on paper, you may be surprised how bright the Aeon can actually sound. It's still easier to listen to relative to the Ether C (w/out additional filters, that is), I think, but measurements can be deceiving. Adding the foam filter is a step in the right direction. I would like to see something with further impact on the response, but, hey, I won't complain for them being included for free. I have plenty of my own damping material to play with. NOTE: Blue = stock (left channel), and red = with the foam insert. CSDs look OK, but not great. The filter helps clean up a few edges. It could be the mild ringing centered around 1-2KHz that makes them sound hotter than they may look in frequency response measurements, but I'm not sure. Either way, not a whole lot to comment on here, positively or negatively.