The Steel Guitar Forum

I have a cheap multi-tester that has an ohms section. The lowest setting is 200 ohms. I connected it to my 4 ohm JBL-D130 and it read 3.6 ohms. I connected my 8 ohm TT-12 and it checks 5.5 ohms. I know ohms can be approximate when measured. I just need to know if my cheap multi-tester can check ohms by just connecting to the speaker terminals or is a more sophisticated instrument required.

Speakers are AC devices so the rating is for AC impedance. The impedance varies with frequency. Your meter reads DC resistance and the readings you’re getting are pretty normal.

Fred

Sounds like it's working right. The ohm readings measured this way should always read a bit lower than the rating.

I checked with the speakers not connected to an amp. Should they be connected to an amp so they are "hot" when checking?

Nope. You get better readings when disconnected.
Matter of fact, never try to check ohms on a powered up circuit. Best case the ohm meter will get confused, worst case it will blow it out.

The rule of thumb is to multiply the DC resistance by 1.3

Gary, are you saying I should multiply the ohms measurements by 1.3 ?

Yes, that is exactly what I'm saying. While DC resistance is not the only component of impedance it is the most significant contribution.
Here is a brief rundown https://www.kevinchant.com/uploads/7/1/ ... edance.pdf .
I hope this helps
Gary Jones
I ain't dead yet.