What makes speaker's sound big?

Audiogon, where the science of audio goes to die ....

For a point source with an unencumbered spherical radiation, SPL reduces by 1/R, or it is 1/2 at double the distance (-20log(0.5) = -6db. Sound intensity (power) reduces by R squared. Human's are sensitive to sound pressure (SPL).   For a perfect line source, SPL reduces by 1/sqrt(R), or 1/squrt(2) at double the distance of -3db.


However, no line source is a perfect line source, and walls, floors, and ceilings contain the spherical distribution so the equations above are guides, and the reality is somewhere in the middle.

And "full" is still a factor of SPL at your listening location, over an extended frequency range, no matter how you achieve it, and what gets to you is a combination of direct and reflected.  Larger room, and the reflected is reduced. Damped room and the reflected is reduced. Line source and there is less direct loss with distance, but less reflected energy to contribute to the arriving SPL.  Larger drivers provide the ability to achieve higher SPL with less cone movement at low frequencies. Multiple small drivers can achieve the same thing.  You still need to move the same amount of air, area*excursion, to achieve a similar pressure wave.

MA,
Wow pull something useful out these comments will require use of a divining rod.
-"Buy a Raven amp. pair with the DIs and die a happy man"!
-"Buy a Maggie"
-"Ohm Walsh!"


Singblues says you can trade 4 ea 15" woofers in for 2 ea 5" Harbeths and with enough placement experimenting achieve
a nirvana similar to his FSMs. 

My experience- Similar room size as yours. I use the Tannoy FSMs now and have tried the Joseph Audio Pulsars to see
how it compared. 
After a few days of "adjusting to Pulsars" you may forget what
you liked about the big boys. i.e. they move a lot of air and you feel it in your chest. 
I let the Pulsars go to another friend and am happy with the Tannoys.

The answer to your question only brings up more questions.
Good luck!!

The things that make a speaker sound big are driver size, cabinet size, and low end capability. You can not defy the laws of physics so when you go to a small speaker with subs you get an uneven wave launch of sound on the mids and highs that does mesh right with the bass unless the three pieces are larger like a big wide baffle mid high tower with a large subwoofer.

^^^ --- Well this is pretty much made up nonsense --- ^^^

Not much else to say. This is just ignorance of how to properly integrate subs.

Martin, no point source speaker is going to produce a life sized image. What you get out of them is a mini sound stage like you are sitting all the way in the back of the hall.

Sorry but you are wrong.... Too much play with equalizer not enough with acoustic...

We must use not only passive treatment acoustic , but activated room acoustic...

My point source speakers produce a life size image filling all my room, the sound dont come from the speakers at all...

Why?

My room is activated by my devices, my grid of Helmholtz resonators doing great work and some others devices...

It is not the type of the speakers that matter, it is the relation between the speakers and the room first, and the method for activating the room...

The sound is not only a passive result of the boucing back of waves.... This is simplistic acoustic....It may be the result of a controlled pressurized dynamical atmosphere with different devices....Helmholtz teachings....


What make the sound big? many factors some here have already mentioned; but the main factor is an ACTIVATED room, there exist 2 necessary and COMPLEMENTARY ways in acoustic of small room: the material passive treatment, and the active non electronic one....Helmholtz resonators grid are very powerful....


Anyway even if you forget my acoustical remark, think about the absurdity of your affirmation.... All designers of point size speakers would have designed speakers condemned to always produce a "mini soundstage" betweeen the boxes? Asking the question is answering it....

The fact that you have never set a pair of point source speakers the right way yourself is a more probable answer....Sorry....

By the way i know how magnepan can sound in a bad room and in a better one....Each type of speakers ask for his type of room geometry and proportion and acoustic treatment and specific acoustic control....You dont put magnepan anywhere and small box speakers anywhere also....