In Reply to: hi there! Email me? posted by Timbo in Oz on November 21, 2008 at 13:42:17:
The spheres had two fathers - Michael Brown and David Jones, apart from Olson on wave-launch, they did not know that curved surfaces have very low bending modes as well.
Eg, a sphere made of different radius rings of MDF, clamp-glued and then turned smooth, would be a lot lighter than concrete, and faster. And very probably quieter than Celestions 600 and 700 boxes. I've heard both models and despite disappearing they till sounded like boxes.
IME for the Flat 5 the box enclosures threw away just about everything the spheres got right, and got in the way of much of what the Flat5's get right.
Floor loading does help with the baffle diffraction step (BDS), but adds early reflections in front of the enclosure.
The model 2's # (Coral Fl5), and M3 * (the Fostex 2-way), and M4 #(2 x Coral Fl5) all had BDStep issues. *No LP filter/ # no filters. I've always wondered what an M4 would sound-like if the second 5 was only fully effective from their -3db BDS point and on down IE as a 1.5 way design, ;-)!
Near to wall mounting on adjustable articulated arms strikes me as likely to keep most of the sphere 2's launch right, and give some broadband bass boost. I used to run my LTLoan pair in the bedroom on tall stands about 2.5feet out. Articulated? Hard to wall for when you're not listening closely, and out for close attention sessions. But they still can't/don't do bass. More than half the 5's I find are burnt out, by people trying to MAKE them do bass.
IMO the best way to use a pr of 5's in sphere2's is from no lower than 150 and all the way on up. The lower down the steeper the high-pass needs to be. Just like with single pairs of 57's - ;-). As the link, in the post above, sets out.
Did you ever find a fill-in / 'super' tweeter to go with the 5's that was worth the trouble? I've heard the Foster/x RPT in that role (the one with the round mounting plate) but thought it needed a small wooden sphere - ;-) as it was audible and placeable. I'm thinking of that small 16?mm Dayton?!
What is your opinion of pole-piece extensions - misnamed phase-plugs - for a pr of metal dust-cap Flat 5's? IE remove the dust caps and put a turned 'bullet' on the central magnet pole?!
JBTW David J taught me how to set-up sprungies, and I now have their Linn jig!
http://www.theanalogdept.com/susp_tim_bailey.htm
TIA
WarmestTimbo in Oz
The Skyptical Mensurer and Audio ScroungerAnd gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
http://www.theanalogdept.com/tim_bailey.htm
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Follow Ups
- why? I live in Canberra and have known the sphere guys from the 1970's - Timbo in Oz 15:18:28 11/21/08 (0)