How to measure ohms of a cab?

[stevie]

Assuming the measurement you took was correct, those drivers are not 8 ohms. I've never seen an 8-ohm driver with a DCR that low.

Let me tell you about a trick some speaker companies have been known to pull. They fit 6-ohm drivers to their cabinets and label them 8-ohms. Why? Because it makes the speaker louder than the competition in the showroom. It only becomes problematical when you connect two speakers to one amplifier channel. However, at loud volumes where you would expect the amp to complain, the speaker impedance rises, neatly solving the problem.

The worst example I've seen of this was the Zeck 15/3 PA speaker, unknown over here but a best-seller on the continent a couple of decades ago. They had the nerve to fit a 4-ohm EV driver to their 8-ohm box. The magazines raved about how much louder it was than anything else but none of them ever bothered to measure it.

Edited December 7, 2012 by stevie

[alexclaber]

The old EA CXL112 is an 8 ohm nominal cab with a 4 ohm nominal woofer. I heard it explained as that once the voice coil is up to playing temperature it's then measuring more like an 8 ohm woofer, though that doesn't help if your amp shuts down before that point...

[Bill Fitzmaurice]

[quote name='alexclaber' timestamp='1354886040' post='1891607']
The old EA CXL112 is an 8 ohm nominal cab with a 4 ohm nominal woofer. I heard it explained as that once the voice coil is up to playing temperature it's then measuring more like an 8 ohm woofer, though that doesn't help if your amp shuts down before that point...
[/quote]Quite the hocus-pocus that, but not surprising from a company that claims to make transmission lines when they are not.