Damping factor or watts?

Hi Rodman99999,

I don't blame you one bit for fighting to keep the family farm.

92 dB is higher than average efficiency, I'll admit. Whether or not it qualifies as true "high efficiency" is a judgment call - over on Audio Asylum they discussed at length where to draw the line, and if I recall correctly the consensus was 96 dB. You and I will probably have to hire lawyers and go to court to settle this issue. Or maybe we could have a cage-fight? We could sell tickets and split the proceeds, maybe both be able to buy some new gear (allow me to recommend a nice low-damping-factor amplifer...).

Sorry, couldn't resist.

Okay, back to the RMAF rooms. No autoformers were used. The only things that made the speakers "low damping-factor friendly" were a smooth impedance curve and a fairly low port tuning. The port tuning is actually user-adjustable, so the speakers can be adapted to different room acoustic situations, but this feature is also useful in amplifier matching. With a solid state amp, a higher tuning frequency would probably work better.

Duke

Audiokinesis- It's been a few years(like maybe 26) since anyone threw any Thiele-Small parameters at me, so I'm still picking up the pieces of my shattered brain here! From what you're describing: I'm going to guess the woofers are about 8" based on the Vas? If that's so: with a fairly high mechanical(11.69) and electrical(.35) system loss, they sound like they might have a relatively stiff compliance. The moving mass isn't all that high, so I'm thinking a fairly short throw(or single/flat wound) voice coil. If I'm all wet here, I'm certain you'll let me know. I don't expect any mercy!!

Funny thing Atmasphere: I've got that very paper saved on my computer. I've never liked negative feedback loops, probably what endeared me to David Hafler(his early ideas). I wondered if there was a connection between your name in here and the OTLs. The lack of a hyphen threw me(not so hard to do at my age).

Rodman99999, I chose those woofers based on low thermal compression, suitable combination of bass extension and efficiency in a size box that I could live with, and sufficiently smooth response between 1 kHz and 2 kHz. I'd have liked higher voice coil DC resistance in both cases, but went with what was available. These woofers were not picked out as being uniquely "low damping factor friendly".

The heavier-cone woofer is a 12" with plus or minus 7 mm of linear excursion, and the lighter-cone one is a 10" with plus or minus 6 mm of linear excursion. Both are prosound drivers with unusually low efficiency (and consequently good bass extension) for prosound units of that size; most prosound 10" and 12" woofers are really midranges with efficiencies in the upper 90's.

Duke

Audiokinesis

Thanks for the info on Atma-Sphere S-30 - I checked and it looks very very interesting.