All you really need is one woofer and one tweeter to have a great sounding speaker. Multiple drivers can create more problems than they solve. Close your eyes and let your ears decide.

starfish, thanks for the reply. But I wonder why so many expensive speakers have such an array of woofers if they interfere with each other?

There are many theories to how to make a good sounding and good looking speaker .

Some manufacturers use one large driver for bass. 12" to 15" diameter. One drawback to this is it makes for a rather wide speaker cabinet.

Other manufacturers will use multiple smaller drivers for bass. 6" to 10" diameter. This gives them the woofer surface area desired for good bass response but allows a narrower cabinent face.

This does get interesting. I have B&W speakers at present with one 8 inch woofer per speaker. Is that good enough?

If YOU like the sound of them, then yes, that is good enough.

BTW I have B&W speakers, too. DM603 Series 3. They have dual 6.5" woofers.

Here is a link that might be useful: DM603S3

most electronic stuff - especially "consumer" brands, its all marketing play -- whos got this "biggest", "more than" blah blah. IGNORE all that...size matters not one bit (as Yoda whould say) -- there are very high end loudspeaker systems using nothing but very small drivers, and very cheap crap using dual 15" woofers. i.e. its NOT about size...its about engineering. YOUR ears will determine what sounds best for you in your room..nothing else. Example, I have a Martin Logan tiny 8" subwoofer that will rock the foundation of my house. Listen with your ears and ignore absolutely everything else spec or size wise. Also if you can avoid at all costs any big box, big brand store, and hunt out smaller independant audio shops...youll get access to audio driven products and knowledgable salespeople and service. Many will also let you audition products in your own home. Happy listening!