Kub3, Shin, I don't want to give too much away about my speakers too soon, give it a little more time  Going well though.

I was going to try a pair of D3004-660000 or the Seas Millennium from Linkwitz fame. The Millennium has more excursion and was measured on a slightly smaller baffle hence its earlier measured roll-off. On the other hand driver design has probably progressed since the Millennium so the subjective performance might be better in the D3004.

Something to consider might be a Hi-Vi D8.8+ with the dustcap removed (4" voice coil!) and a ScanSpeak D3004 (just the right size without face plate) mounted in the pole piece.  4th order Xover at about 1.5KHz. If you replaced the dustcap with a small hole for just the dome of the tweeter and space the tweeter back enough for the negative excursion of the cone it would make a very interesting monitor IMO.

Mr. Devil, it is true that all speakers have audible distortion. If they didn't they would be indistinguishable from a live performance in the room, including vertical spatial information which is not possible to reproduce from a stereo speaker without false trickery playing with phase in the recording.