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Romy wrote:

"...Let pretend that you play a normal some kind of horn with a lot of air in it. The air drives the driver impedance down..."

I'd like to understand this; correct me if I'm wrong:

As soon as the membrane of a horn-loaded driver starts to move, that membrane sees the air mass located in the horn as a load. Because the air inside a horn is confined by the walls of the horn, this load will be greater than what the membrane would see if operating in free air or as a direct radiator. The result is a pressure inside the horn fluctuating between greater and lesser than normal atmospheric pressure outside the horn; the difference being most pronounced at the throat of the horn. 

It would seem fair to say that this load physically "impedes" movement of the membrane, and that a horn-loaded driver will experience greater resistance to movement, or greater physical impedance than would an identical but non-horn-loaded driver.

Are these conclusions correct? If they are, then does that increase in physical impedance equate to an increase in electrical impedance as seen by the amplifier? If so, can it not be said that "driver impedance" has in effect been increased by the load (the air in the horn)?

jd* 

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