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JBL LSR 28P Odd Behavior

DinoA

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Hi all!
New member, so apologies if this question is in the wrong section!

I have an early set of JBL LSR 28Ps that I bought new back in the day, and all components are original. I mostly monitor at low levels (less than 80db) while working. Lately, one of the monitor’s tweeters has been “slow to engage” when I turn the monitors on. What I mean by that it the tweeter seems attenuated, or even off. However, once I give the master volume a little more “gas”, the tweeter will come alive again and work fine for the rest of the session. What would cause this? Is the tweeter itself beginning to fail, or is the built-in amp or crossover components for the tweeter?
 

Koeitje

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I'd check the wiring, sounds like bad connection? But then again, I'm not an expert.
 
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DinoA

DinoA

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I'd check the wiring, sounds like bad connection? But then again, I'm not an expert.
Hi Koeitje,
It was the first thing I checked. I re-seated all the internal connections, but the problem still exists.
 

Filio45

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@DinoA good timing with your post. I have something similar with one of my 6328p, after lending them to a friend! The tweeter still has output but obviously less compared to the other speaker, easily audible. I haven't noticed any difference with giving that speaker more volume. It's down as soon as you turn it on and stays that way. I'm not really sure if it's outputting less high frequency or the same frequencies with less output, or both. Anyone got any suggestions? I've yet to open them up to inspect. :confused:
 
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DinoA

DinoA

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I'd be starting here rather than the crossovers or speakers themselves.

I guess these would have been produced and purchased 20 - 22 years ago?



JSmith
Yes, I bought them sometime in that 1999-2001 range.
 
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DinoA

DinoA

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Dried up ferrofluid?
I don’t know, maybe…but if the ferrofluid did dry up, I don’t understand why the tweeter will work fine after a brief volume “goosing”.
 
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