Impedance change!?


Hi, 

I'm after some expert advice :)

I got hold of a pair of Celestion15s recently and they blew a channel on my Sharp SM1122 amp (it was my Dad's) which accepts 4-16 ohms. 

Impedance is a rock solid 5.2 ohms on one speaker, and a wavering 11 ohms on the other (so it's highly suspect!) The label says 4-8ohms. 

I've googled of course, but can find no reason for this difference and would appreciate any input on how I can resolve this issue. 

Kind regards, 

Paul 



gtfour1154
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.