Two medium size woofers Vs One big size woofer

I have two Vandersteen 2wq subwoofers. Each has three 8 inch drivers driven by a 300 watt internal amp. They have a "Q" control on the cabinet back to increase or decrease the tautness of the sub response. The three 8" drivers with the "Q" set low provide amazingly tight bass. If you want it to boom, for home theater movie reproduction you just turn that dial up.
I just bought a new disc player and power cord for my system amplifier. The disc player is rendering a tighter bass profile and the power cord (7 gauge) has really given heft and gestalt to the bass and system sound overall.
On the other hand, one large driver can do a nice job especially if it is used in a servo controlled system.

How many subwoofers have you seen using ten 6" drivers?

I wonder how the larger surface area of a large woofer factors into the acceleration factor.  A large driver with twice the surface area of a smaller one only needs half the movement of the smaller one to move the same amount of air.  That has to factor into the equation.  I think you'd need to understand the relationships between size, extension, distortion, etc. to be able to have a meaningful opinion on this.  Big drivers are definitely better for deep bass.   You'd need 9 6" drivers to be the equivalent of my 18" sub and in order to have a comparable excursion the surround would need to have as much surface area as the cone.  That would have to contribute to distortion.

"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!