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Originally Posted by mgboy /forum/post/14172105
4 FiCar IB18's. Maybe 6.
Originally Posted by penngray /forum/post/14172144
4 18s wont do it, I have 4 and 2000W and I can not get 125dB, although my room is HUGE (20000+ cubic feet).
what is average size? Room gain might get you there....
I would get 8 to be sure and power them with 6000+ watts
btw, have you been on the IB cult site to ask the same question?
Originally Posted by Funky Waves /forum/post/14172223
Depending on how much room gain you have. 16 FI IB18"s would be needed, if you only have 14db room gian, 8 if you have 20db room gain, 4 you would need 26db room gian which might be pushing it. The best way to figure it out would be to take a sealed box subwoofer that at a certian displacment should be giving you XXdb's put it where the IB outlet will be and see how many db's you accualy get, then you can determin how many you need. Or better yet get one IB driver biuld put it in and see how much output you get, then double the number of drivers for every 6db more you need.
Haven't been to the cult yet.
What kind of numbers are you getting with your 4 18s?
penn. =P Mighty big living room
Originally Posted by penngray /forum/post/14172294
You know, I have not run them extremely hard in a long time and I dont have the measurements. I should try to get some this weekend when the family is away.
Originally Posted by Willd /forum/post/14172252
From what I understand, gain that low should be pretty large.
Great. Your 18s are in an IB?
Don't you guys dial in a sloping house curve or something? (assuming electronics can take it in the first place, which gotta be...else why chase this low in the first place ). So including room gain, a flat response won't cut it, will it?
Originally Posted by bossobass /forum/post/14173807
Ilkka claims that the harmonic distortion will be easily audible, even with a 30dB reduction of the higher order harmonics which will realize zero gain. I disagree with that assessment, but being that there is virtually no data on this subject, there is little to be gained from further discussion of this particular aspect. Still, Ilkka is a formidable source of logical processing of known facts, so I wouldn't discount his opinion without your own tests.
Originally Posted by mgboy /forum/post/14172166
I was thinking of something normal - not a house plan penn.
Originally Posted by noah katz /forum/post/14174094
"It becomes an input signal rather than a sound wave because it has no chance to appear as a complete sound wave."
Interesting point, though I'd say that from the listener's perspective there's a wave because he experiences a pulsating pressure and ssociated perception of sound and feeling.
"Pressure Vessel Gain (demonstrated by the gain seen in cars) is in effect in every room at 5Hz. This is in addition to Boundary Gain, which can technically be 18dB with a corner placement, less losses due to the construction of the boundaries."
Isn't that double-dipping? I think PV gain *is* boundary gain, where the wavelength is so long that anywhere in the room is effectively near all of the boundaries.
Alternatively, I believe you'd need to invoke wave reflection, and as you said above, wave behavior is absent sufficiently below room mode freq.