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Hales Revelation 3 Crossover Help

I'm looking for a crossover schematic for a pair of Hales Revelation 3s  or a good picture of a factory unmodified one.  It's a long story, but without one, I will be unable to save my beloved speakers.   Any help or direction would be fantastic.   I've only been able to dig up one image that isn't clear enough to find the problem with mine.

steelneyes
steelneyes OP
3 posts
 
Erik_Squires
Would this explain why he said they measured out at 3 ohms when he was done?  Thought they were 4ohm nominal?

timlub
2,039 posts
 
This speaker uses 4th order crossovers with all film on top. The concept that Erik is referring to should not happen with smaller tweeter caps when only tweeter caps are replaced.
There have been at least 2 other threads where the ESR issue was raised.... I say at least, because on 2 occasions, I received private messages from the ops looking for help to work through the problems. Each issue was different. First Verify that the correct replacement diaphragm was used also If the diaphragms got to hot putting them in, that can make the changes that you are referring to. I don’t drink, how about a hamburger.
timlub
2,039 posts
 
According to the impedance curve posted, these speakers used a 4 ohm woofer and most likely a 6 ohm mid and tweeter. The woofer at one point drops to below 3 ohms, this is most likely why you are reading a 3 ohm dcr. Nominal means no more than average impedance over its operating range.
Also,  the method that Erik is referring to,  you would add the appropriate resistor to the tweeter only (wherever the caps were replaced)
steelneyes OP
3 posts
 
I appreciate the responses!  I informed the person that worked on them so that he can read through your thoughtful answers.   Unfortunately, I have zero skills as far as speaker repair.  Originally I tool them in because the tweeters were getting increasingly harsh sounding and he confirmed that the ferrofluid had began to fail and was solidified.  
I am unsure exactly what capacitors were replaced.   I can build a house or fix just about any outboard boat motor out there but knew better than to attempt messing around with the Hales.  
He is a knowledgeable person with a good reputation.  We're just trying to get through my issue so I can back to listening and not thinking about speakers and systems. 
erik_squires
16,058 posts
 
This speaker uses 4th order crossovers with all film on top. The concept that Erik is referring to should not happen with smaller tweeter caps when only tweeter caps are replaced.

Pretty much true, though I could imagine if a zobel or notch filter was employed it might.


I was referring to the general use in a low pass filter. Ideally you'd use something like DATS to measure the speaker impedance and that of the components that were removed. That would give you a definitive answer.



Best,

E
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