Hi fellas. Here are my thoughts on and after the phaseplug experiment.
The Process: Removed the drivers from the boxes. Used a few drops of petrol to soften the rubber-based adhesive used to fix the dust cap to the whizzer cone. Removed the dust cap with a tweezer slowly and carefully. Placed the drivers in sun for half an hour to dry off the petol. Put a thin circular line of Quickfix gum under the plugs and placed them on pole piece. Then dried under fan for about six hours with the drivers lying front side up.
Physical Aspects: Near the bottom, the plugs have about a couple mm gap between their outer plane and the voice coil. Although a little wider than what I like, it proved very handy during placing the plug on the pole piece and centering it without adhesive touching the voice coil. Oriented vertically, the top of the plugs protrude above the drivers' height by 4-5mm which initially looked a little odd to me, but after fixing the drivers to the enclosure they look quite nice in horizontal position. Also, (!) yesterday the dye looked deep-brownish than how they look today - deep purple, though I can't say that I hate it. Besides, the cone color isn't black either - more of a deep bluish-gray, with which I feel the plug color is well in "sync" haha. The hole from turning process is visible in front of the plugs, which doesn't bother me too much but I think I will put some m-seal on both to fill the holes and also maybe make the front a little convex or pointy... undecided as of yet.
Sonic Aspect: Now, did the plan work out in the audible domain??? The answer is YES!
No dustcap and voice coil cavity almost filled - so the 6KHz peak is gone and I can go full-band loud without covering the ears. The speakers are placed with about 4ft between them and used to gradually attenuate treble material as I walked from listening position towards the middle of them - at that point the emergent virtual mono in the middle was almost totally comprised of mids, and very little of highs. But now things are different. That gradual attenuation is gone and standing close to the speakers in the midpoint I can clearly hear trable. As it seems, the drivers now have much better dispersion than before. HF level feels more equalized all over the room - in other words the treble fills the room now, instead of firing like lasers! From the listening position I can feel a big increase of soundstage and improvement in stereo projection.
My first choices of test material was Bombay and Taal, and all the tracks came out with a higher dimension of clarity than I was used to get from these speakers. Due to the HF "lasering" being turned off, treble doesn't overpower the vocals now and I can hear the mids much more clearly and can dig deeper into the music without much effort (in loss of a better phrase to express it).
Overall, a success! Hurraayyy!!!!!!




Here are a couple pictures of the speakers after placing the new phaseplugs.
Cheers!
shaan