On Wed, 20 Oct 2004 16:30:17 -0400, "Arny Krueger"
wrote:

"Computer Prog" wrote in message
. com
Lets say we have a subwoofer driven off a 500W amp and it can output
120db at a specific distance.

Lets now assume that we have the same sub driven off a 250W amp and it
now produces 117db at the same distance. (120db - 3db for half the
power).

Finally lets add another identical sub driven off another identical
250W amp and it also produces 117db.

What will produce more output, the single 120db sub driven off the
500W amp or the two 117db subs driven off the two 250W amps?

I think we have been here before. . .


Presuming that the subs are linear, the amount of energy transferred into
the environment is the same due to conservation of energy.

Well yes, 500 watts of power in, 500 watts of heat out. The room
warms up just the same.


However, two identical subs will not have the same radiation pattern as
either sub. Two subs radiate their energy over a slightly smaller region,
because the larger effective diaphragm will be more directional. If the
measurement position is some distance from the subs, the SPL at the
measurement mic will be higher for the two identical subs, presuming
conventional side-by-side mounting and otherwise normal use.