KLH 5 surround sealing question(s)

[drspiff]

I've been reading about sealing the surrounds of the KLH speakers and have received some Magic Speaker Stuff from RoyC. So you are probably thinking I'm about to ask a question about sealing the woofer surrounds.

Alas, no my friends. The woofers are sealed including the dustcaps, and they now move like they are supposed to. My question is about the 2 mid range speakers. They look like they have rubber-sealed paper surrounds.

If this is the case, should I also seal these surrounds like the woofer surrounds? What about doing the dustcaps on the mids?

And then what about the tweeter? Looking past the metal screen, the tweeter also looks like a rubber-sealed paper surround.

So many surrounds, so little time...

 

[tyella]

Not sure about the tweets, but I put a coat on my mid surrounds.

 

[Guest105]

Well, there is apparently an old KLH service bulletin which directs repair personnel to seal the mids if/when a speaker is in for repair....but I don't know why. The mids are in their own enclosure, and even if their surrounds are somewhat porous, I don't see how it would make a difference (since they don't operate in the lower frequencies anyway). But I assume that it doesn't hurt, either.

On that note, you should make sure that the holes in the midrange enclosure (for crossover wiring) are sealed. KLH used corks, and these have often dried out and broken or fallen out. Plumbers putty or something similar would work quite well.

You've probably already done so, but if not....I've found that the "classic" KLH models benefit from recapping as much or more than any other speakers I've restored (many, many!). They used low-end components to begin with, and now that they are 40-50 years old you can be assured that their ESR has risen and their capacitance has changed...quite significantly, in many cases.

 

[alteclipsch]

I have a newly acquired pair of 5s and will seal the mids. The tweeters, being behind a metal mesh, I'll leave alone. Those cones move so little, I can't imagine it would make a difference.

I posted the bulletin on the model sixes from KLH. It mentioned the six and the twelve point five, but nothing else.

 

[gbroot]

I agree with KC that applying the sealer to the mids most likely doesn't do much, but I did do it to mine cause I read somewhere around here to do it! Probably applying a second coat to the woofer surrounds is the better way to go if you have just one jar of the sealant.

 

[vsat88]

I did not coat my mids. however I did make sure that mid box was sealed as well as possible. In the future I will coat them as well however they sound great as is. Rebuilding the crossovers was a must for mine. Best improvement sound wise by far. One thing though..I used electrolytic, bi polar electrolytic Caps. I am sure someone will curse me here however I like the sound and I think it keeps more in line with the whole classic speaker sound. Besides, try to fit polys on that board and when you are thru spending 200.00 on caps..LOL, I dont think so..

 

[Guest105]

You certainly have to be a bit creative to fit modern caps, but the cost is quite a bit less than $200. Dayton metallized polypropylene caps would run about $75 (1% tolerance) or $45 (5% tolerance) to do a pair of KLH Fives. Film/foil caps would be quite a bit more.