What's Tuning Frequency?

[jamo]

It doesn't seem to be related to the F3 or the F10. Could someone explain it?

[johnddaugherty]

> It doesn't seem to be related to the F3 or
> the F10. Could someone explain it?

The tuning frequency is determined by the relationship of the acousto-mechanical properties of the driver to the net internal volume of the enclosure in which it is placed and, to a lesser extent, to the damping in that enclosure. When the net internal volume is such that the Fs of the driver, the F3, and the Fb, or box frequency, are very nearly the same, then what you have is termed the 4th order "maximally flat" alignment. You could raise the tuning frequecy by using a shorter duct and/or a smaller net internal volume. The effect would be to raise the center of the frequency band where the port's output is significant, broaden that range somewhat, and produce a peak in the response curve below which the roll-off curve would be more steep.