I finally modded my YH-3s this evening, after much prodding from Kabeer to get it done so I have a better reference for the YH-100 mods. First thing I did was ring the driver with Blu-Tak and seal it off to the front bezel.
I had tried the driver completely taped off with just the Smeggy felt in teh cup and it was great sounding mids/highs, but limited bass. So I went back to Ludoo's scheme with the Moorbrook over the driver's holes. Mine are apparently VERY bass heavy! Ludoo's bass heavy mod with the Moorbrook over the Smeggy felt was still under damped far too much. I taped off three holes on each side, the three outer most holes that weren't easily covered by the felt disc. Back to over damped. Took off the tape on two sides. Man, back to under damped again. Can six holes make that much difference? YES! I ended up taping all three holes on each side off again, then cutting out the middle hole. Eight holes taped off, four partially covered by the felt, the rest covered by the felt. I also trimmed the Smeggy felt undersized and ringed it with a thickness of Moorbrook the same height as the cups.
And the result was exactly what I hoped for! Great bass to go with the sweet mids and highs. I'm in awe of the sound, and most importantly for me, pianos sound like live pianos! WOOT! WOOT! Thanks Ludoo, cetoole, and dB, but especially Kabeer for pushing me to mod them!
Now I'm ready to tackle the YH-100s and T20s.
Oh yeah, pics will follow later. I have them, just need to upload them tomorrow morning. Crashing for the night.