Two medium size woofers Vs One big size woofer

"Acceleration factor" is the ratio of force or motor strength (Bl) divided by moving mass (Mms). It ignores cone area, and is imo therefore misleading.

Let me illustrate why: Suppose we are comparing a single 10-inch woofer against four 10-inch woofers, and they are all identical. So the acceleration factor (the ratio of motor strength to moving mass) is the same for the single 10-inch woofer as for the four 10-inch woofers. But it would be a mistake to claim that the ability of the single 10-inch woofer to accelerate air is the same as the four 10-inch woofers. The four woofers can accelerate four times as much air as the single woofer.

And ultimately it is the ability to accelerate air that we are most interested in. 

As for whether a single big cone is better for bass than multiple smaller cones, assuming the capability of the multiple small cones adds up to the equivalent of the single big cone, I believe that I could get better performance out of the multiple small cones by distributing them to different locations on the loudspeaker enclosure to improve their interaction with the room.  There would be tradeoffs for doing so, and the cost would almost certainly be much higher for the multiple small cones.  

Duke

No speaker has ever given me the attack, and thump of my old D-9 wardogs!

  They were , and still are amazing monkey coffin speakers!

Yes, there are tradeoffs  either way. Can't have it both ways. 

Another factor to consider is a large, 15" or so, woofer properly loaded into a well designed bass front horn can make any combinations or 7" of 5" drivers ashamed of themselves.  The transients, impact, tunefulness, definition and clarity is unequaled by other systems for bass reproduction.

@kingharold --

Another factor to consider is a large, 15" or so, woofer properly loaded into a well designed bass front horn can make any combinations or 7" of 5" drivers ashamed of themselves. The transients, impact, tunefulness, definition and clarity is unequaled by other systems for bass reproduction.

I wholeheartedly agree. Myself I’ve chosen the tapped horn principle - do you know of it, and have you heard any tapped horn subs? A traditional front loaded horn would have suited my requirements very well also, but that’s another discussion. It’s great to see the sound of horn bass/subs acknowledged - you put it just right.

What’s interesting is how the horn acts as a force multiplier in being an acoustic transformer, and thus a horn-loaded 15" like you mention acts and feels quite differently compared to a 15" (or bigger) direct radiator. Even compared to ported subs with 2 x 18" drivers per cab, a horn-loaded 15" to my ears feels more effortless, present and "malleable" somehow, as if the bass flows in more organically and naturally with the rest of the frequency spectrum. Ported 2 x 18" is typically more of a "pounding" experience that potentially stumbles over itself with very demanding bass lines; 15" horn-loaded bass is more a floating/flowing experience that vibrates, or even shakes the whole air volume in the room, making for a very present, enveloping and tactile feel. It’s a shame so few have heard horn (sub) bass..