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Late 70s LaScala buzzing midrange


tswei

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Just brought home a

Used pair of Scalas from the 70s. I am generally very pleased, but when I ran a series of tone tests, the left unit had a loud buzz on the 80 & 90Hz steady tones. When i pushed firmly on it the sound stopped, but it took quite a bit of pressure. Is the mount loose or is the driver bad?

It did not happen on 100, 70 or lower, just those two frequencies. Thoughts?

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He did say the buzzing stopped when he pushed on the midrange driver. Maybe a dried up driver gasket or loose driver?

But, with 80 and 90Hz making the noise, it points to a leaky bottom bass bin gasket.

He has a couple of things to check.

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Thanks so much for all the suggestions, everyone!!

This is an awesome community and I am over-the-moon to finally be part of the Old School Klipsch community. This has been a long road since first hearing a vintage pair of K-Horns playing a classical piece at a party in the late 80s. Could not get that sound out of my head, and now I finally have that sound running in my basement.

Better late than never.

Cheers.

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I'm dissecting my KHorns for new crossovers, and just yesterday I noticed that the driver on one of my

squawkers was loose, about 1/8 turn. Everyone should reach around back and tighten the driver every

10 years or so. Or after a household move.

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See my posts in this thread here: http://community.klipsch.com/index.php?/topic/143229-my-newold-pair-of-la-scala/#entry1634397

..and also here: http://community.klipsch.com/index.php?/topic/130970-is-it-the-al-3-or-the-squakers/?hl=gasket

Basic heritage maintenance items that'll go a long way to restoring their original sound, for only a few bucks and couple hours of TLC.

*edit* Fixed broken links

Edited by Quiet_Hollow
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I think I have found the problem. Got it upside down and removed the bottom panel to reveal the bass bin.

I played 80, 90 and 100 hz in a loop and leaned over the thing (it's big) and looked closely at the woofer to see if something was detached/resonating etc.

So as I am leaning on the bottom sub-panel ( the piece sandwiched between the bottom panel I just removed and the vertical walls of the bass bin), I realize the buzzing has stopped!! Seems like the sub-panel/vertical wall join is vibrating and my leaning into the bin with all my weight on it stopped the resonance.

(http://www.flickr.com/photos/97729757@N05/)

You can see in the attached picture that the factory used staples to join these. I guess after 40 years of hard rocking, that join is loose.

My plan to to sink countersunk wood screws where each RED "X" is on the image. Not sure how many I need, maybe I've got too many. Any thoughts?

scala bass fix.pdf

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Good detective work. [Y] Countersunk screws sound like a good idea. One every six inches or so should be plenty. 1-1/2" to 2" long should be good.

Naturally, you'll want to check the other speaker in the same way, since they're both the same age and the second one could start to show the same symptom anytime.

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You can see in the attached picture that the factory used staples to join these.

I believe they are actually finsihing nails, used in a nail gun. They use ring nails for a lot of the cabinet work, which usually hold quite well.

Bruce

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