polk 6x9
"Eddie Runner" wrote in message
. net...
MOSFET wrote:
I can imagine a
scenario where the 6" distance has gone up and has started it's way back
down while the 9" distance is still going up.
ARE YOU NUTS!?
That wont (CANT) happen!
the 6 inch part will rise and fall the EXACT same rate and distance the 9
inch part will move. THEY WILL RISE AND FALL AT THE SAME TIME, NOT ONE
BEFORE THE OTHER...
Eddie Runner
I think he's referring to the cone flexing at different rates due to the
additional mass over the long ends. Depending on the stiffness of the cone,
surround and even elevation (air density) this certainly can happen.
Measurable? Probably... Audible? Doubtful...
This can be demonstrated by holding a wooden yardstick or a similar long
thin flexible item (in the middle) parallel to the ground and moving it up
and down. As you speed up, you will notice the ends are no longer moving in
unison with the middle, there is a delay in following the middle section. As
you speed up more, (depending on the stiffness of the yardstick) it's often
possible to get the ends 180degrees out of phase with the middle, ie: you
move the middle up and the ends go down.
This effect would be very minimal on a oval speaker because unlike the
yardstick above, the whole cone is supported by the surround on top, and the
voice coil on the bottom. The cone is much more rigid, likely throwing the
resonant frequency of the cone (and the tendency to "fold" onto itself like
a taco shell) well out of the mechanical range of the speaker.
Even if there was a problem in the "old" days, 3D modeling software and FEA
have put an end to it.
Chris
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