admired , envied and NEVER duplicated ! the Allison convex cone midrange and tweeter!
There is no modern tweeter capable of as wide dispersion as Allison's tweeter. It was innovative than, and it is innovative now as well, by both past and modern standards.
Wide dispersion from conventional modern and old tweeters is possible only with some complex waveguides//phase plugs/slots/lenses/reflectors.
search for the patent ? according to interview w/ Roy there is none !
SM: The transducers used in the Allison One looked proprietary. What were the design criteria for the dome tweeter, dome midrange and woofers?
RA: The midrange and tweeter units are not really domes in the usual sense. They are convex radiators, but each is driven by a voice coil at approximately half the distance from the centre to the suspension edge. Neither has a spider. The cone part of the tweeter, although convex overall, is curved inward and the outer edge is clamped through a very thin ring of latex foam to the mounting plate. Thus the radius of curvature of the cone changes as the voice coil moves, simulating a pulsating hemisphere that puts large amounts of high-frequency energy into the reverberant field all the way up to 20kHz. The midrange unit has a straight-sided cone with a flexible polyethylene edge suspension. It has extremely wide and uniform dispersion over its operating range… as does the tweeter.
Neither is proprietary inasmuch as they’re not protected by patents, but they are difficult and time-consuming to make properly, and they do project relatively far out from the front cabinet panel, which complicates the grille design. They have not been imitated, probably for those reasons.
Roy F. Allison Interview | Hi-Fi | Feature | AVHub
Thanks for the likes folks I'm constantly amazed when I'm looking for something and totally unexpected I run across some gem like I just found above so I'm able to copy paste it and share it with you all
As I recall it started because somebody was trying to say in another group that the Allison Twetter was not the best dispersion of any Tweeter ever and I knew that couldn't be true so here we go Google searching and look what turned up another erudite empirical concise and enjoyable! Explanation by Roy himself!
The technology of the internet and the freedom it gives us to find this kind of thing is just amazing isn't it?
