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Differing bass left to right

CDinMB

CDinMB

Active Member
The issue is with mid 70s Klipsch La Scalia Industrial just cosmetically refurbished and new Crites crossovers. With some critical listening (head in the bass bin opening) I can hear punchier bass coming from one bass bin versus the other. Both are working but one side is significantly quieter and not producing a defined thump. The amps are MC30s both newly rebuilt and I have swapped amps and preamp channels and the low volume stays with the left side bass bin. I have not opened the bin to check the wiring or the speaker. These are separate bass bins. I did find the horn box and old crossovers miss wired so I am suspicious I may have a phase issue. There is no distortion as I would expect with a blown speaker.

Any suggestions?
 
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First, switch the wiring on the quieter bass speaker IF you hear a null as you cross from one speaker to the other. This will put both woofers in phase.

Second, check the woofer is snugly installed. The opening is on the bottom of the speaker for the woofer chamber.

Third, ensure no one stuffed any toys, stuffed animals, etc into the doghouse fold.

Then check the impedances of both woofers. They should be pretty close to one another.
 
I don't have the proper tools to measure impedance accurately, but both bass bins measure 3.9 ohms resistance on the DMM. I will do the other tests today. Thanks for the ideas!
 
Swapped polarity on the left bass bin and had no effect on the sound, it was still quieter than the right channel. Took the Bass bin apart. It was easier than I expected. No foreign items found. The wiring is fine, connected properly. The speaker was mounted solid but I removed it anyway to look at the cone. Only found the traces of an old repair along the edge of the K43-E. It looks like a well done repair, so I doubt this is the cause. Should there be sealer or weather stripping along any of the seams? There is nothing at the speaker to box interface other than the speaker surround, a thin closed cell foam at the bin hatch. Should I add something to ensure a good air tight seal? Also noticed the speaker was reinstalled by restorer in an orientation different than factory. I mention this because there are gasket deposits on the wood and voids on the speaker gasket that did not match up. This alone could cause air to escape. I reinstalled it matching the factory install.

Also, when I gently push on the cone I feel a lot of resistance (this is subjective and I don't know what is normal) and I hear and feel some rubbing and notchy travel. The best I can isolate the sound it seems to be coming from the voice coil not the cone and there is some notchiness in free return. Do I have heat damage?


IMG_3186.JPG
Old repair. Looked at it under 10x and saw no open seams. So, I assume this should perform well.


IMG_3188.JPG
Inside bin shows left behind gasket on the wood. When I bought it the S peaker was not installed the same to use these seals. It is now.
 
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Hard to tell from the photo, but it looks like the repair job may have pulled the cone off center causing the rub. Try GENTLY shifting the cone away from the repair and see if the rub ceases.
 
usedto said:
Hard to tell from the photo, but it looks like the repair job may have pulled the cone off center causing the rub. Try GENTLY shifting the cone away from the repair and see if the rub ceases.
Click to expand...

Took it out and that looks like an artifact in the picture. However, I tried moving it away from the repair and forward/back and it was a bit smoother. Exercised it a bit. Could be my imagination but it got smoother. Put it back together aligning the gasket to the factory position and there is strong bass again!!! I am guessing rotating the speaker so the full gasket was sitting on gasket pieces caused an air gap and twisted the frame. I have a good seal now and it sounds great! Love these speakers! I should probably take the other one apart just for my own piece of mind.

Thanks for all the ideas!
 
The rubbing and distortion comes and goes, I am thinking burnt voice coil, and decided to replace the speakers. Called Klipsch they said they had only cast frame K43s, they won't fit, so I ordered Crites K33 replacements. Just got a email from Klipsch saying they were wrong they found some stamped steel frame K43s. Hmmm. Well, hopefully I will like Bob's woofers.
 
Bob delivered them in 3 days and only 15 minutes to install. They sound great. Good solid bass and no distortion. I like them better than the K43s. Using the Thorens/M44-7 combo they actually thump bass. Definitely not my normal listening mode but something I never thought I'd hear from the LaScalas!
I am a happy camper again.
 
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