One "big" woofer or four "small"?

[Audica]

Which combination will give a better result, namely tighter bass, kick bass, attack ...?
One of 10 inch woofer or four of 6.5 inch woofer per side?

Thank you

[fastbike1]

More drivers are louder, not lower. Which do you want?

As for your adjectives, that depends on the specific drivers being considered. I can think of good and bad examples for each adjective for each size.

[Audica]

I do not want bass less than 35-40 Hz.
To my attention a number of small units that work together, faster and can produce better attacks one big unit.
Of physics. Four 6.5-inch units can produce more energy when they work together. Am I wrong?

[adason]

one 18" woofer!

[adason]

if you do not need so low, find good PA 18" woofer and that will beat any 6.5" crap anytime

[weltersys]

Originally Posted by Audica

I do not want bass less than 35-40 Hz.
To my attention a number of small units that work together, faster and can produce better attacks one big unit.
Of physics. Four 6.5-inch units can produce more energy when they work together. Am I wrong?

Given adequate motor strength, there is no difference in transient reproduction between a single larger unit compared to multiple smaller units that equal the Sd (effective cone area).

Small drivers can have adequate cone stiffness and control with lighter weight cones and magnets, but it takes about four 6" cones to equal the cone area of a single 12" speaker.

[18Hurts]

The only difference is frequency response is not in the equation would be...

Two 8" woofers in push-pull configuration to lower distortion. That is about it, besides...the two 8 inchers would have less issues with 40Hz instead of four 6.5 inch woofers.

[RockLeeEV]

Four of the average 6.5" drivers, in parallel, will have impedance around 2 ohm or lower. That's really what it comes down to... availability of drivers that can work in 4X parallel

[chris661]

I'd've thought that being able to wire series-parallel means more flexibility on impedances than a single driver.

However, taking Sd to be equal for 4x6.5" drivers and 1x10" driver, each of the 4 6.5" drivers will have to move as far as the 10" driver to give equal output.
For a decent 10" subwoofer, 1" p/p of travel is reasonable enough to do. But even for the most specialised 6.5" driver, this is a lot of excursion, and distortion will have increased considerably.
The excursion to driver size ratios mean the 10" driver ought to win in this respect.

Chris

[18Hurts]

Good point Chris,

It all depends on the frequencies you're using with your woofers. If it's below 500Hz, all is well--if you are trying to cross to a tweeter at 3KHz, I'd go for four 6.5's and use two of them with an inductor for baffle step correction.

If it is for below 200Hz, I'd go with larger woofers personally--either two 8's, one 10" or whatever you can handle as far as size goes.