How to measure impedance of 3 way speaker

[audiorp]

I put together a pair of 3 way speakers from left over parts. Xsim told me the system impedance would be mostly 8 ohms but the DC resistance of the system measures 11 ohms. Is there a way to measure the actual impedance of the system? I have a DATS V2. All the drivers are rated at 8 ohms.
Thanks

 

[mlee]

REW (Roome EQ Wizard) has a section that outlines how to make impedance measurements. Its been a while but it boils down to a box with a resistor connected to your speaker, run a sweep and you'll get an impedance plot.

 

[Michael Chua]

Connect your DATS V2 to the speaker terminals and click "Impedance Sweep" button.

 

[audiorp]

I thought the DATS was only to be used on the driver that is not hooked up to anything else. I want to test the system.

 

[Michael Chua]

DATS is not just for Thiele & Small Parameters.

It can used to measure loudspeaker impedances too.

Below is an impedance sweep of my 2-way.

 

[audiorp]

So to be clear, you just hook the DATS leads to the speaker box input terminals? With the drivers wired up to the crossover? And then do a sweep?

 

[mbrennwa]

So to be clear, you just hook the DATS leads to the speaker box input terminals? With the drivers wired up to the crossover? And then do a sweep?

Yes.

 

[Michael Chua]

That's right. It won't damage DATS or your speaker.

 

[audiorp]

Cool, thank you all so much.

 

[head_unit]

DC resistance of the system measures 11 ohms...ll the drivers are rated at 8 ohms.

Sounds to me like something is miswired in series. "8 ohms" would be about 5-6 ohms DC resistance, and 5.5x2=11. Trace your wiring really carefully, and measure the DCR of each driver.

 

[Dave Bullet]

An impedance sweep is the first thing I do to make sure I have the crossover wired up correctly and avoid frying my output transistors. This is especially useful for a 20+ part 3 way crossover

 

[audiorp]

Thanks again. You folks are great.