Richard Crowley wrote:
"John A. Weeks III" wrote in message
...
In article 41a909c9$0$15230$afc38c87@, Don Ritchie
wrote:

Other then the obvious (3 inches), what is the REAL difference
(in use) between 12 inch speaker and a 15 inch speaker.

A well made 15 inch woofer can produce bass that goes slightly
deeper than a 12 inch speaker. A poorly made 15 inch speaker
will just make more mush out of the music.

They also have different polar patterns. I've seen the 12 vs 15
inch discussion a couple of times (re sound reinforcement)
over at news:alt.audio.pro.live-sound

Yes, but once you put them in the cabinet you can play with the polar
pattern anyway by changing the size of the front baffle.

A 15" woofer will have twice the surface area as a 12" woofer.
Therefore it can move twice as much air with the same Xmax. But,
it will tend to break up more `since it has the same cone material
but a longer path to breakup (this is a horrible oversimplification,
but all you really need know is that the breakup modes are different).

What you REALLY care about as far as the depth of bass is the resonant
frequencies of the box/driver combination. I have heard some 10" drivers
with a 16 Hz free-air resonance, and some 15" drivers with a free-air
resonance more than two octaves higher.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."