do piezo compression drivers have an impedience

[tuneman]

as the title says,

i've always wondered, they dont measure anything with a meter!
is there any way of testing them? besides the obvious they either work or don't

[bob91343]

Impedance bridge.

[dangus]

Instead of an impedance bridge, set up a sound card to do impedance tests. Google will find information.

Anyway, piezo drivers are supposed to be mostly capacitive. That might explain why some amps don't like it if you connect a piezo tweeter without some series resistance.

[Steerpike]

They are indeed almost entirely capacitive - so any ohmmeter that uses DC will show open circuit - such a meter only measures resistance, not impedance.
Only an LCR meter that measures with an AC test signal will give the true impedance - which to be strictly correct, is a complex number (i.e. involves the square root of a negative number).