One big subwoofer or two weaker subwoofers?

The SW systems are in the wall because I like the characteristics of a sealed (acoustic suspension) system. There are many drivers suitable for sealed box alignment, but few designed for infinite baffle operation. Also, it is an outside wall.

It is three separate SW systems, each having 15" and 12" drivers. Each driver has it's own amp. This is necessary because the 4 ohm driver impedance discourages parallel operation. Each 15" driver is powered by half of a CarverPro ZR1600 digital amp, 600 watts. The 12" drivers are powered by 250 watt SW "Plate amps" and their signals are equalized for phase and frequency response. I intend to use the 12" drivers to tweek the overall system performance, but in practice little or no equalization is needed. The enclosures are about 7.5 cubic feet each. The front baffle of each enclosure (which resemble coffins standing on end) is covered with acoustic foam to absorb some of the back radiation from the Magneplanars. The whole SW system is concealed behind fabric wall covering. In spite of its massive size, it is nearly invisible. (WAF you know). At present I am using 80 Hz 24 dB/octive for crossover. This makes life easy for the Maggies.

Because I designed and constructed the whole thing it didn't cost too much. I reckon it was about $3200, including 2550 watts of power amps, and sheetrock, plaster and paint to remodel the living room. Besides, the project was interesting. Better than dropping $3200 in a one hour visit to an audio shop.

if you really beleive 8-10 inch is faster than 15 -18inch..your wrong....8-10 quality is better than 15-18 crap' but 15 18 sota, come on !!!!If your room is big enough...if you are using monitors than 8-10 is better

Mavilla, are you really considering different subwoofers or did you start this thread just to see the blood? :-)

I agree with Rives, depends on a lot of other things. There is no "one size fits all" answer. His link along with other usefull info. should help you decide on which may work best for your system and room.

This thread has some great info. on bass and speaker design along with what can happen as you try to blend the wrong sub with your speakers. While the thread is not about subwoofers..the principals apply for a smooth blend. http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1032037028&openfrom&61&4

Fast bass Slow bass is another good read...http://www.soundstage.com/maxdb/maxdb061999.htm

You may also want to do some reading at this AA forum, http://www.audioasylum.com/forums/rives/bbs.html

Dave

"Faster". What does this mean? Here is what I think.

Frequency response is part of the story. A subwoofer that is flat to 400 Hz will handle 80 Hz better than one that is flat to 200 Hz.

However, a loudspeaker that reproduces the LF waveform perfectly can still be "slow" in the sense that the amplitude of the sound builds up slowly, and perhaps persists after the electrical signal is cut off. This characteristic does depend partly on the size of the driver, with large ones tending to be slower. However, apart from the enclosure, the full story involves not only the size of the driver (actually the moving mass of the cone) but also the strength of the motor that drives the cone: the voice coil, magnet, and amplifier. My 15inch drivers, for example, have 4 inch voice coils, massive magnets, and are driven by powerful amps. They are not slow. The characteristic of a driver that would correlate with slowness is a ratio of motor force/volt to the moving mass.

Also, I must mention my view that most very low frequency sound sources are, by nature, slow. A large organ pipe, for example, does not sound forth at full volume when activated, and it continues to emit sound after it is turned off, not to mention the hall resonance that can be strong for several seconds. I think that what many people take to be "slowness" in subwoofers is really the nature of the sounds they reproduce.

Finally, aren't subwoofers fun! How often do you see similar debates about tweeters?