Sub output: Is it the woofer size or the rated RMS

Shadorne - I wasn't thinking of slap and 5kHz when I mentioned 10" woofer's bass definition - for that bass enclosures have tweeters. I was thinking of low frequencies. 10" woofer arrays have better controlled/damped (shorter) bass while 18" woofers tend to produce "woolly" bass. The question is what is cheaper - 18" woofer or 3 x 10" woofers (to obtain the same surface area).

"Why do we use eight 10” speakers? Because we learned early on that 10” speakers work much more efficiently than fifteens or eighteens—and if you put eight 10” speakers together, you can move a much larger column of air."

Mmarvin19 - excellent point. Bass players know that 10" speakers provide the best compromise between power and bass definition and use arrays of many 10" speakers.

Speakers in array made in the same enclosure work better. (Acoustic impedance lowers, resonance frequency drops down) Making simple reasoning 18" speaker moves 3.24 times more air than 10" speaker. To avoid membrane bending (cone breakup), that Almarg mentioned, membrane has to be 3.24 time thicker and in order to keeps everything proportional coil and magnet have to be 3.24 times larger to move 3.24x heavier membrane with 3.24x more air pressure. Am I right? Speaker people - are you there?

One correction - membrane of 18" speaker should be 10.5 times heavier because it should be 3.24 times thicker and the area is 3.24 times larger. That is probably why definition is getting poor (too heavy).

Shadorne - I was thinking of three 10" woofers versus one 18" woofer (same area).

Drew - Thanks. I forgot about xmax.