Technical Questions

Re: dead woofer?

goingtoMontana — Wed, 15 Jul 2009 21:17:26 GMT

I tried that before i opened them up and realized that the woofers were different to the touch. Well I already took these by bob crites house (I am also from Arkansas) and he said they were probably toast. So he traded me out for his k-33 replacements (since i am using them for home use). Thanks everyone and thanks Bob.

Ryan

Re: dead woofer?

Just_Strummin — Wed, 15 Jul 2009 14:49:11 GMT

Liar, liar, woofer on fire!

Change your speaker wires and see if you're getting the same problem out of the other speaker. If so, it may not be your speaker.

Re: dead woofer?

goingtoMontana — Sat, 04 Jul 2009 04:44:11 GMT

Thanks for the information. So I lied and I have not pulled the woofer out yet but it is on my list of todos. I knew when purchasing these speakers that one of the tweeters was out so it was not a surprise when there was another issue, but I got a deal so I cannot complain. Hopefully I will have the woofer out by sunday or so and can diagnose the problem.

Ryan

Re: dead woofer?

djk — Sat, 04 Jul 2009 03:45:03 GMT

" I noticed that when I tapped the cones that the working one reverberated while the broken one sounded dead and flat."

See if you can even move the cone, my guess is you have a shifted magnet (the cabinet having been dropped at some point in time).

If the cone doesn't move, cut it out of the frame with an exacto knife. If the gap the voice-coil fits into is pinched over to one side buy another K43. If the gap is OK it may be re-coned.

http://www.speakerrepair.com/ocsrepairprice.html

OCS can re-cone it for about $60 plus round trip shipping.

If the magnet is shifted they can sometimes repair it, or come up with another frame suitable for re-cone. If your magnet is shifted I would inquire about them coming up with a suitable frame as the cost to repair the magnet and the savings in not having to ship it to them will probably be enough to cover a suitable frame.

Re: dead woofer?

William F. Gil McDermott — Fri, 03 Jul 2009 22:44:10 GMT

I think you may have a partially blown woofer.

When you buy something used, it is not too uncommon that the units are being sold because there is an issue.

In many cases a speaker driver fails completely because the voice coil winding wire is physically broken due to too much heat. Or the little tinsle wires between the terminal and the moving diaphragm breaks for the same reason. Sort of like a fuse blowing. In that case the voice coil tests as an open circuit electrially and the unit is dead.

In your case it is proably a warped former - melted glue - partially displaced voice coil winding. The former is the cardboard-like cylinder on which the voice coil wire is wound. There is also some glue holding the windings in place.

There can be long term high levels of drive which heat up the voice coil, like a toaster. Then the glue melts and the windings come out of place.

The mechanical issue is that the voice coil on the former is sitting in a relatively narrow ring-shaped gap. With deformation due to heating, the voice coil bloats or deforms and binds in the gap.

The result is that the speaker driver works to some extent at high freqs but the bass is gone. A normal diaphragm assembly will move smoothly when you push gently with an open hand and indeed resonate. A warped and binding voice coil feels jammed or gritty.

My guess is that you will find this when you take the woofer out of its housing.

BTW I took apart a pair of failed woofers owned by a young relative. They were totally dead so I took an X-acto knife to the diaphragm - voice coil units. The windings were out of place, glue was melted and there was charing.

In many cases of second hand purchases, it is the tweeter which has been damaged. That was not the case with those. I can only guess that someone drove them with the bass control all the way up and the loudness switch "on".

Wm McD

dead woofer?

goingtoMontana — Fri, 03 Jul 2009 16:07:47 GMT

I am fairly new to the forum and to klipsch speakers. I just bought a pair of industrial la scalas, and there seems to be something wrong with one of the woofers, so I am defering to the wisdom of the forum. The woofer that seems to be messed up does not make any buzzing or rattling noises that I would associate with a blown woofer, but is much quieter than the other. I initially thought it might be the crossovers but since mine are splits I was able to switch out the tops and verify it was simply the woofer (unless there is another crossover in the woofer bin that I cannot find). So I opened up the woofer bins to look at these bad boys. I noticed that when I tapped the cones that the working one reverberated while the broken one sounded dead and flat. Cosmetically the cones look fine to me. I plan to take the woofers all the way out today, but as of yet I have not. I have the k-43s if that is relevant information. Any help to diagnosing this problem would be greatly appreciated.

Ryan