How to measure impedance of a 412 cab?

Low_fidelity2100

New member
So my 412 is wired for 4ohms (4x 16ohm speakers wired parallel)...I've checked the wiring and its definitely wired as it should be. But I decided to try and check the impedance with my Multimeter, just to see/make sure.
Set the meter to the 20k ohm setting...Touched the Meters leads to the speaker cable...got a reading of 0.00...Tried different settings on the meter, kept getting Zeros. Thought maybe the meter was messed up, so I measured some pickups...And its reading them just fine...Then I tried to read a single speaker, and again, got 0.00 (and yes I know the speaker works)...

The cab works fine, sounds fine, all speakers are in phase, and working, etc...I know its wired correctly, I even rechecked tonite just to make sure. But I can't figure out why I can't get any reading at all off the cab, or even single speakers...So obviously I don't know how to go about reading a speakers/cabs impedance/resistance (I thought ya just measure it like a pickup, and then Round the resistance up to the nearest standard speaker impedance, i.e. 3k = 4ohms, 6k = 8ohm, etc..)...So yeah...anyone wanna explain to me what I'm doing wrong? haha
 
Re: How to measure impedance of a 412 cab?

if you've plugged a speaker cable into the jack, touch the red lead to the sleeve, black to the tip of the cable.

and make sure your multimeter is set to the 200 setting (ie ohms, not kilo-ohms). 1 kohm = 1000 ohms. It's not working because you have it set to 20 kilo-ohms.


Edit: I just took a reading from the supposed 8 ohm speaker in my practice amp. I got 7.6 ohms.

Similarly, the old Celestion G12-65s are supposed to be 15 ohms, but you can use them as you would a normal 16 ohm speaker.
 
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Re: How to measure impedance of a 412 cab?

if you've plugged a speaker cable into the jack, touch the red lead to the sleeve, black to the tip of the cable.

and make sure your multimeter is set to the 200 setting (ie ohms, not kilo-ohms). 1 kohm = 1000 ohms. It's not working because you have it set to 20 kilo-ohms.


Edit: I just took a reading from the supposed 8 ohm speaker in my practice amp. I got 7.6 ohms.

Similarly, the old Celestion G12-65s are supposed to be 15 ohms, but you can use them as you would a normal 16 ohm speaker.

Thanks! On the 200 setting, I get 4.3...seems higher than it should be for a cab wired 4ohms, but at least its something!
 
Re: How to measure impedance of a 412 cab?

as long as your roughly in the range, it should be fine.

don't forget, you're also reading the resistance in the cable, and the cab's wiring in addition to the speakers.
 
Re: How to measure impedance of a 412 cab?

If you want to measure something of 4 ohms, why did you set the mutimeter to 20000 ohms?
 
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