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Help with Sonus Faber Extrema issue

I have a pair of Sonus Faber Extremas hooked up to a pair of Parasound JC1 monoblocks.  One of the speakers periodically will exhibit signicantly lower volume (down to almost no volume) in the middle of a listening session.  It seems to occur when during more dynamic passages and also when the amps have been on for a while.  If I turn everything off for a few minutes, the problem usually goes away.  I reversed the speaker cables at the speakers and the same speaker still exhibited the issue, so the issue is with the speaker.  What could cause this problem?  Could it be a bad connection somewhere in the speaker?  Could it be that crossover parts need to be changed due to age?
wcheng2
mijostyn's avatar
mijostyn
8,252 posts
 
wcheng2, You need a volt /ohm meter. You can get one cheap.
  https://www.amazon.com/AstroAI-Digital-Multimeter-Voltage-Tester/dp/B01ISAMUA6/ref=sr_1_4?crid=25A5L2Z8KUDEW&keywords=volt+ohm+meter&qid=1571097024&sprefix=volt+o%2Caps%2C160&sr=8-4
There is a short in that speaker. Again, if they are still under warranty let the dealer deal with it. If not you are on your own. You have the good speaker for comparison. Good luck,

Mike
daveyf's avatar
daveyf
2,837 posts
 
Winston, I am almost 100% sure your problem lies with the x-over. The Extrema's need a lot of power...but can, like any speaker, be over driven. That and the age, means a trip to to the tech. 

@mijostyn, the Extrema's haven't been made for decades...warranty service isn't in the cards, LOL.
imhififan's avatar
imhififan
2,136 posts
 
The tweeter pair should measure open circuit because of the cap in series .
The bass will measure what ever the resistor is in series, (does anyone know what that is?) . https://ibb.co/BNtQdtJ
George,

Extrema treble section has no series capacitor but a inductor connected in parallel with the tweeter and a resistor in series to match the output of the woofer.

https://www.hifisentralen.no/forumet/attachments/diy-og-utvikling-ha-yttalere-forsterkere-etc/228418...

Post removed 
georgehifi's avatar
georgehifi
10,312 posts
 
(mine came from Stereophile, your doesn’t say, except diy)

Which ever xover it has, the OP has to say to us.
What’s actually happening, is there nothing from the tweeter or nothing from the mid-bass
or very little from the tweeter or very little from the mid-bass
Only then can this problem be sorted before dismantling the speaker.


https://www.hifisentralen.no/forumet/attachments/diy-og-utvikling-ha-yttalere-forsterkere-etc/228418...
If it does have this xover then the mid/bass unit should be what the voice coil is of that driver my guess around 4ohms).
And the tweeter should be around 7.5ohms (because of the 2 x paralleled 15ohm series resistors and the almost short of the inductor)
Cheers George
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