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using a Celestion G18Q-400 in a 4Pi-18 [message #42714]

Wed, 15 October 2003 14:59

bikehorn
Messages: 14
Registered: May 2009

Chancellor

I have the opportunity to get a G18Q-400 for a good price. its specs don't totally match the Omega Pro 18's, but it'd still like to use it(i'm going to use this cabinet for electric bass). because it's such an obscure and unknown driver, it won't be going anywhere fast, so i have plenty of time to buy it.

i emailed Celestion and got some specs:

D 0.38m
Re 6.4ohm
Fs 32Hz
Qms 7.06
Qts 0.244
Qes 0.252
Mmt 99.2g
Cms 0.25mm/N
Vas 459l
Bl 22.4Tm
Rms 2.8kg/s

will the speaker sound bad in this cabinet? what changes should i make, like port length? thanks

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Re: using a Celestion G18Q-400 in a 4Pi-18 [message #42717 is a reply to message #42714]

Wed, 15 October 2003 17:45

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

PiAlign recommends 4.0ft3 tuned to 50Hz using a rectangular 5.8" x 10.3" port that's 9.2" long. Response is nice and flat with f3 of 60Hz and f10 of 40Hz. A four π-18 cabinet is a good choice also, providing an EBS alignment having a -3dB shelf from 40Hz-100Hz. Response is nice and flat in the shelved region with a slight 3dB rise through the 100Hz - 200Hz octave. Considering the shelved region as the baseline, f3 is 40Hz and f10 is 30Hz in the four π-18 cabinet.

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ahhhhhhhhh! hardcore physics!! [message #42729 is a reply to message #42717]

Thu, 16 October 2003 16:03

bikehorn
Messages: 14
Registered: May 2009

Chancellor

Thanks Wayne! some of that went over my head though :(

i understand the PiAlign Part, and right up until "A 4Pi-18 cabinet is a good choice also"...and the rest is over my head except the 3 dB rise in 100Hz-200Hz range. are your results good or bad? thanks for the help.

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Re: ahhhhhhhhh! hardcore physics!! [message #42732 is a reply to message #42729]

Thu, 16 October 2003 21:55

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

Both are very good. The smaller cabinet recommended by PiAlign generates response that is optimally flat, but the larger four π-18 cabinet generates an EBS response curve that provdes deeper bass extension. Both are good solutions; Your choice depends on your needs. If these will be mains, the smaller cabinet is good and if subs, then the larger might be better.

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