So, what exactly does a compression chamber do??

[NV&H]

Can someone please explain the theory and function of a compression chamber? Why do horns need them?

[GM]

Greets!

Well, first and foremost, it protects the very fragile diaphragm if required. Second, it keeps the driver from comb filtering with itself. Third, it can be used to reactance annull the horn (apply the right amount of acoustic compliance to offset the horn's air mass loading) to obtain peak performance down to Fc.

GM

[mwmkravchenko]

In a rear loaded horn the compression chamber acts as a capacitance to create a high pass filter if used as a chamber behind a driver that has the cone radiating into the air.

A capacitance blocks low frequencies at the rate of 6db/octave below the corner frequency. The corner frequency is determined by the size of the chamber.

Mark