Can anyone help educate some haters over here?
http://forums.presonus.com/showthread.p ... 408&page=2

And why exactly does a horn increase impedance?

Impedance is a combination measurement. It is NOT strictly resistance. It represents capacitance, electrical resistance and mechanical reisistance. Ohms are merely a convenient method of measurement. Impedance is increased by the resistance of the air column in horn throat, thereby raising the mechanical resistance of the driver. It is measurable.

Stick a ohmmeter on a raw driver, it will read the same as it does in the box. You have to do actual impedance measuring to determine cab impedance. For most cabs, it's the same as the driver. Horn loaded subs are the exception.

I don't do internet arguments anymore.

No thanks. There's no point in trying to educate someone who already knows everything there is to know and won't hesitate telling you so.
The impedance load of the air in the horn is higher than if the driver is exposed directly to the open air.

Is that an electrician's forum?