slaps = acoustic lever?

jbell · 18th February 2009, 01:47 AM

Dumb question... but with the different size surrounds front and rear... is an earthquake slaps, effectively the same thing as dr. geddes acoustic lever? and is that why earthquake claims +6db?

Ron E · 18th February 2009, 09:29 AM

They probably claim +6dB because passive radiators don't suffer as much from port compression, although suspension nonlinearity can still be a factor.

jbell · 18th February 2009, 01:52 PM

Earthquake claims that a combination of the 'M' surround and the big roll surround that it's linear over 1.5" of travel (3" p-p). I have to believe that the differences in the surrounds presents different pressure areas on one side vs the other, which would be a lever.

I know in earthquake subs I've watched with the slaps, I see the slaps appear to move MUCH further than the driver.

My thought was that this is a lever, and it solves the issue geddes had with having a device mfg'd that would have sufficient travel, and not prematurely fail.

If this is a lever.. another interesting part to me, is that both the slaps, and the lever are patented..

Ron E · 18th February 2009, 10:17 PM

Quote:

Originally posted by jbell
I know in earthquake subs I've watched with the slaps, I see the slaps appear to move MUCH further than the driver.

My thought was that this is a lever

PR's generally move at least 2-3x as far as the active cone they are coupled with assuming they are the same size.

18th February 2009, 09:29 AM	#2
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	They probably claim +6dB because passive radiators don't suffer as much from port compression, although suspension nonlinearity can still be a factor. __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley

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18th February 2009, 01:52 PM	#3
jbell diyAudio Member Join Date: Apr 2003 Location: .	Earthquake claims that a combination of the 'M' surround and the big roll surround that it's linear over 1.5" of travel (3" p-p). I have to believe that the differences in the surrounds presents different pressure areas on one side vs the other, which would be a lever. I know in earthquake subs I've watched with the slaps, I see the slaps appear to move MUCH further than the driver. My thought was that this is a lever, and it solves the issue geddes had with having a device mfg'd that would have sufficient travel, and not prematurely fail. If this is a lever.. another interesting part to me, is that both the slaps, and the lever are patented..