Does subwoofer + bookshelve=full range speaker?


I am sort of new to this hobby so this may seem like a dumb question.
I always wonder if add a good sub to a bookshelve speaker do you get a same performance as the large full range speaker.ie if you add a subwoofer( assuming a good one) to B&W 805 or Martin logan entry level model . do you get the same performace as N801 or prodigy or more because the subwoofer in many instance will go even deeper than the full range speaker?
if not why not?
a1126lin

Showing 1 response by a1126lin

maybe 801 /805 wasn't such a good example. but that say if you use the same midrange and tweeter but one has a smaller woofer 6 inch vs the full ranger model 12 or 15 inch. I think it would cost much more to build a 12/15 inches full ranger speaker and it still may not go as deep as a power subwoofer that crossover with smaller speaker . many powered subwoofer can reach 20hz where as alot of full range speaker don't get anywhere near there. I think the N801 goes down to 37hz.
Obvious you don't get someting for nothing. if it were that simple , manufacture would sttop building full range speaker , and we all be using sub/sat for our system.