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Dumping : How (LS and rope caulk)


vacs2000

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Hi

Ok, I've got to Home Depot and bought 4 boxes

of rope caulk. Now what ?

By reading the BB here it is not clear how one

puts this stuff around the middle horn. My impression

was that you completely envelope the metal part (K400)

of the mid-horn. Then I show the Web page of T.Brennan

where he has a half photo of his dumping where he only

put the putty on the edges somehow..

So any additional help ??

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Vacs,

Dynamat is best for the squawker, but some rope caulk comes in handy there too.

Like Al says, wrap the tweeter up till it looks like a little snowman. This means at least two or three layers deep.

If you dont' have $60 to blow on dynamat, you could cover the squawker with rope caulk. It would take a lot but I bet it's cheaper. Again we are talking several layers.

The most important part to dampen, IMHO, is the throat of the horn -- the part closest to the driver. The second most important part is the mouth, the part furthest from the driver.

The large spaces in between beg for dynamat. But you could just slap layers of rope caulk on there, too.

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Wrapping the horns

Last night I reversed the roles we normally hold, my speakers and I. Instead of my worshipful genuflection before their presence, I gingerly placed the 100 pound babies face down on the floor, and removed their backs.

Following the advice of J.W. Gorman, insane poster on the Klipsch BBS, I wrapped the horns in my big, old Cornwalls (serial # 32x57 and 32x58).

The wraps are temporary, simple, easy, low-cost and extremely effective tweaks. It does indeed dampen the harsh ringing and jitter of the mid-range and high-end horns. It is one of the easiest, most cost effective tweaks that any Klipsch owner can do...

Inside the cabinet, the walls were padded corner to corner with a thin, light gray cover like the bed ticking of yore. The padding was framed with a lattice of delicate white string. It looked like a miniature padded asylum cell from 1890.

The big K-33-E woofer looked surprisingly light, more like a Radio Shack woofer: No large frame or huge magnet. In fact, the magnet was as thin as the padding.

The K-51-V metal mid-range horn was more impressive. It rose almost a foot high and was topped by a rounded magnet. The K-77-M tweeter by comparison was much smaller than it looks from the outside: No bigger than the yellowing coils on the B-2 crossover board.

Packing lines of gray caulking cord like a potter working on clay, I layered the throats of both horns. I only put on one layer and have yet to add another. But the horns are covered up to their heads in gray jackets - only their heads peak out of the top. Once impressive black horns, they now looked like small asylum inmates, side by side, tall and tiny, straitjacketed in their ancient padded cell.

The caulking cord is soft weather stripping window putty sold at Home Depot for less than $5.00 in 30 and 90 linear feet rolls. I used 120 feet. It comes in 1 1/2" wide flat strips easily torn and pasted by hand. Each speaker took about one hour of network TV; who wants to be a millionaire when you can do projects like these?

You can also use Dynamat, but compared to the ease of the rope caulk, why go through the bother?

Next, I placed ¾ thick black rubber washers underneath the crossover boards. The washers were the thickest in the plumbing section and cost $.47 a piece. Finally, I rubbed the walnut shanks of the Cornwalls down with lemon oil, just like the fine through bred horses they are, and set them back up again.

The effect of the tweaks was immediate and wonderful. Most of the clamor and ringing was gone from the high end.

I re-played the last CD, Michael Frank's Blue Pacific, in order to hear the contrasts and the tone. It sounded soft, gentle and warm. 8:00 on the dial was the fighting point for my little miss sensitive ears and I. At 7:55, I like it higher at 8:05, she likes it lower. But she liked it and did not ask me to turn it down.

Before the tweaks, Bruce Sprinstein's Born to Run CD played with a feeling of harshness. Even though I wanted to CRANK his music, I had to keep turning down the volume. The high end was too hard - too harsh; I blamed the age and analogue equipment of the recording.

But after the tweaks, the Bruce was painless. Likewise, with a Nimbus Natural sound CD, the Hayden trumpets rang like church bells in the valley.

The big old horns still suffer from harsh treble ( a peak at about 5 kHz is said to be the problem and custom ALK cross-overs will fix that). But, this tweak is simple, easy, low-cost and extremely effective. It does indeed stop the harsh ringing and jitter of the mid-range and high-end horns. The high-end speaker still tweets, but the mid range horn no longer squawks. It is a classic fix for a classic problem of classic speakers.

Like many of the other tweaks, it was simple, fun, reversible and worthwhile.

Strongly recommended: Thank you, insane poster J.W. Gorman!

------------------

Cornwalls, Bottlehead 2A3 Paramours, Dynaco II, Rotel, KSW200 & LF10

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Wow! K51V ! A very rare beast indeed.This was the ceramic magnet version of the alnico K55V by Atlas with the two port phase plug.After this the Cornwall went to the K52H by Hepner and the Klipschorn went to the K55M by EV.

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Colin,

thanks a lot for the detailed description of your tweaks. You wouldn't be able to post a picture of the material you used for your horns because, and that is rather embarrassing, I have only a vague idea what rope caulk is. As English isn't my mother tongue I have consulted various dictionaries but didn't find any translation. Am I right in understanding that it is a material that is used to insulate windows and is soft like a kind of clay that can be turned into various shapes? Does it stick to the metal of the horn when pressed onto it and will it not become dry? Sorry if these questions are EXTREMELY stupidRedface.gif

Anyway, thanks for bearing with me.

Wolfram

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Hi Dubai2000,

I bought my rope caulk at Home Depot, a building supply place here. It is sold in with the insulation material and supplies and it is just as you described, soft and pliable. I used it to dampen the horns in a pair of Belles and both Dynamat and rope caulk in my Khorns. The product I bought is actually called "Finger Tip Rope Caulk". It does stick to the horn, it does not dry out and is easily removed if you don't like it.

Good luck!

------------------

Ed W

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  • 2 weeks later...

At last I found the right material in one of our local DIY shops. For all German visitors to this wonderful board it is something called ' plastic-fermit'and it is sold in tin cans of either 250 or 500 gr. For the sqaker horn and the tweeter of one Khorn I almost needed 2.5 Kg! and about three hours work. The second speaker will be fixed during the week and if the sound continues to develop the way I think it does, then the speakers will not only be less harsh, but also produce a somewhat 'cleaner' sound. Damping the horns seems to be like cleaning an old painting: all the dust and dirt (i.e. ringing) disappears leaving the colour of the music purer than before (and so far I am only talking about one layer and one speaker!)

As has been written before: a great tweak for very little money and definitely worth the time spent fixing it!Smile.gif

Wolfram

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  • 19 years later...

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