Impedance change!?

Speaker impedance varies with frequency, so the ratings you're using are "nominal" or average, and you can't expect them to match a volt-ohm meter. But if you measure the same way they should measure the same, and they don't, so something is wrong. In other words probably not just the amp that's blown.

Hi Paul,
I strongly encourage you to measure the impedance using something like DATS V2 or Room EQ Wizard with a jig.

Miller is correct in that a multimeter which measures impedance at DC is not a helpful tool, but they should measure the same. 

The DATS or REW tools however can tell us a great deal about what's wrong.  You may alwo find DIYaudio a better place for these conversations.  You can measure your speakers, post the results, etc.

Five ohm resistance is about right for an 8-ohm speaker. Eleven ohms means there is a broken wire or connection somewhere.

Just open up the crossover and figure out whats wrong. Its not rocket science. Figure it out. 

+ 1 gs5556 or lost a portion of the XO including a driver or a driver alone. Some amps go haywire and the DC goes HIGH. Adcoms were BAD for it.. behind leaky electrolytics on the signal boards. I’m actually looking at one. 565 MB Adcom.

It would blow the woofers, cook the voice coils, especially with 6 db first order, NO way to weed out destructive DC current (no cap there) or fuse usually, POOF!

Just a guess.. look to the woofer give it a sniff, if your looking to repair it anyways..

The amp.. It’s time ay? Dad helped all he could, unless he’s got another spare amp..

Happy Happy.. hunting that is..

Regards

Thank you very much for taking the time to reply (apart from Kenjit of course!), I really appreciate it :) 

I'll check wires and see what I can find, I'm aware the DMM doesn't give an accurate figure, but I just need ballpark at this stage of troubleshooting. 

I was told the crossover doesn't affect impedance, but I'll look into that now thanks to your advice. 

Kind regards, 

Paul 

I was told the crossover doesn't affect impedance, but I'll look into that now thanks to your advice.

Hahahaha, well that is not correct.

https://speakermakersjourney.blogspot.com/2016/12/crossover-basics-impedance.html

Multimeters are super basic, and at the drivers can test for the coil not being open or shorted, both bad, but can't really tell you the impedance of the drivers in audio frequencies, just DC.

Best,

E

Thanks for the link Erik, this was obviously the right place to go!