I forgot to take pics, but I added three strips of micropore tape to the rear of the drivers in a 6 pointed star config (so the centre is layered three times, and some parts of the outer edge are not covered). I didn't experiment here; just randomly laid it down that way.
The sound is interesting. My frequency sweeps are kinda wobbly and a couple spots in the midrance feel oddly damped. And I'm still getting distortion in the bass at moderate volumes. If I had to judge purely by test tones and sweeps I would think I did a terrible job. Judging with music though, I am utterly surprised at the result. Bear in mind that I just finished doing a writeup for a bunch of portables (here) so I'm approaching it with a super critical ear... but wow I'm just digging how this sounds. The separation of layers is better than the DT1350, and the visceral touch of separate notes is easily perceptible. The only other ortho I can compare directly to at the moment is a Realistic Pro30, and while the Pro30 reaches lower without distortion and can deliver more punch, the detailing isn't even close.
I wish I had another T40v1 to play with. I'm thinking it's mostly the interaction of the driver and larger angled cup that produces this feeling. The sound doesn't hit hard (and it really can't without distorting), but it doesn't have to when each little note reaches out and tickles your ear.
