Tempur Mod Update
So I had some time to try Tempur one last time. This time I cut it down to between 1/8" and 1/4" around the edges, and slightly less than 1/8" in the region directly behind the driver. Well, using this little Tempur yields results similar to cotton, but maybe slightly better. It leaves the sound only slightly modified, your head will still vibrate quite a bit to the sound of the bass. Not enough containment for me, maybe enough for you.
Conclusion: Getting the right amount of Tempur is tricky as the devil and could keep you up nights, but as a pure dampening material, it is the most effective I've tried so far, even if I failed to find the exact amount that yields the best dampening without too much curtailment of bass.
Then it hit me. In listening to this latest Tempur mod, all of a sudden I had a flash. Why am I still getting so much vibration? Well, duh, dummy, it's because you are dampening the wrong thing.
What is passing on vibration to the rest of the frame? Is it the wooden earcups to which you are applying all this damping? No. It's the driver assembly, the round plastic housing of the driver that is transmitting all this non-musical information. So why am I trying to damp the ear cups, which are only *responding* to the vibration generated by the driver assembly? You are treating the symptom and not the cause.
The problem is that the only mod I've tried so far which would have damped the driver assembly was when I used a huge chunk of Tempur that, when squeezed into the space behind the driver, actually made contact with the rear of the driver assembly and held it firmly in place. When that was done, as you will recall, a LOT of bass information was cut out, in an unacceptable manner.
Much to my chagrin, this opens up a new area for damping, namely the driver assembly itself. Damping this will need a material that can cling to the assembly without smothering it like the full Tempur mod did.
I don't know where this is going right now or what I will do. But I have a few other materials headed my way that I will try, while also considering how to *gently* damp the driver assembly portion of the Denon.