Rope Caulk Results

[J.4knee]

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On 3/7/2005 4:01:29 PM colterphoto1 wrote:

J4- how thick did you pack the rope caulk on your ls horns. 8 boxes? WIll it fall off it it's too heavy?

About how much should I put on my Cornwall Horns K600 metal?

Michael

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Michael,

4 boxes per horn are what that equates to. One box continuously wrapped will not cover a K 400. So I used a second, third and finally a fourth. I wrapped it from just in front of the rear mount to about 1/4 inch from the end and then back wrapped it until I ran out of the last box. This is what it took to deaden the ringing of the horn when you tap it. It is about 1½ layers or wraps of caulk. The stuff sticks quite well, you just pack it by pressing it to keep in on. You keep wrapping it on unitl the ring disappears.

[djk]

"Dennis, I was trying to point out the spider web bug screen in that tweeter in the picture."

I knew you knew what it was, I was just concerned someone new might try and remove it.

Man, that thing is dirty.

[Seadog]

Here is a caulked K600 for a Cornwall.

[Seadog]

That horn was caulked by forum member Good2Bhome who came by a few weeks ago to show me how to properly caulk a horn. This is Mike in progress.

[Seadog]

Here is a caulked horn in a Vertical CW. You may also notice the P-trap I built and installed. I installed the P-traps about a month before the caulk (did not want to change two things at one time). I think that the P-trap made a more dramatic improvement than the caulk, although both are must-do tweeks for Cornwalls (IMO of course).

[djk]

Nice job!

[Seadog]

BTW, the Cornwall horn takes about 65 feet of the rope caulk to complete (one layer).

[BS Button]

Wonder what the effect would be if you took your horns and had them treated with a 1/4" of Rhino lining?

[3dzapper]

Wonder what the effect would be if you took your horns and had them treated with a 1/4" of Rhino lining?"

"Same thing, more money. For horns that are hard to get at/remove like LaScalas, Dynamat or asphalt damping sheet from Parts Express is easier to use.

Rick

[psg]

The openning in the back of my La Scala's is on the small side; it doesn't go the full width of the speaker as I have sometimes seenm in pictures. Should I remove the horns to do this? Will I kill myself trying if I don't? Will it be easy to remove and put back?

[ram87]

Seadog what is the P-Trap and what does it do???? and what other mods have you done?? ram87

[J.4knee]

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On 3/8/2005 9:21:35 PM psg wrote:

The openning in the back of my La Scala's is on the small side; it doesn't go the full width of the speaker as I have sometimes seenm in pictures. Should I remove the horns to do this? Will I kill myself trying if I don't? Will it be easy to remove and put back?

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I would remove the crossover first. Then try to work the horn out. I am not quite sure what the rear of you HF bin looks like or what you mean by "it doesn't go the full width of the speaker", picture may be best.

[BEC]

In my experience, it is lots easier to remove and reinstall the horns in a Lascala if you first lay the Lascala down on its front.

Bob

[Seadog]

"In my experience, it is lots easier to remove and reinstall the horns in a Lascala if you first lay the Lascala down on its front."

That goes for the Cornwall also, especially when working alone and trying to align the holes to re-install the horn.

[psg]

Thanks guys! When I have some spare time, I'll do this mod! Maybe when I update/upgrade the crossovers this summer.

[Seadog]

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On 3/8/2005 9:30:53 PM ram87 wrote:

Seadog what is the P-Trap and what does it do???? and what other mods have you done?? ram87

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The P-trap is a frequency trap that eliminates 9kHz going to the K-55-V driver. This driver is supposed to fall off naturally at around 6kHz, however, for some reason it flares up again at 9kHz and can create a harshness. It is simply a 0.10 mH inductor in parallel with a 3.0uF capacitor on the squawker's positive lead. Search the forum for "P-trap", there are several good threads on the subject.

To my ears, the P-trap also seems to clean up the sound from the tweeter, adding more high end detail (because the squawker is now dead above 6kHz).

Aside from the caulk and the P-trap, I've done nothing except experiment with various capacitor types in the type B crossovers.

The best "tweek" (for two-channel listening) was setting up a derived center channel Cornwall and going with tube amplification (Scott/NOSvalves).

[ram87]

Seadog thanks for the info Is'n thecrossover for the cornwall/LaScala at 6K???? isn't it sharp enuff??? or is something not right?? to stil be worhing at 3K above crossover sounds like crossover not sharp enuff i could be worng. What is the frequ range of the K55 ram87

[sfogg]

Another good thing to use for damping is 'Plumbers Putty.' It is sold at Home Depot and is inexpensive for pretty large containers of it. Stays soft so you can sort of push it into place without removing the horns if desired. Did a good job of killing the ringing on my Altec horns.

Shawn

[colterphoto1]

Thanks Seadog, good explanations and excellent photos. Looks like that's slabs of the mortite cut and placed on the flatter sections of the horn, then just run concentrically around the throat area. So you just press it on like clay, then 'smoosh' it all together and it really sticks and won't fall off? Cool!

I'll second that request for info on the P-trap, it provides protection from a 9 kHz bump in the horns response as I've recently read. So that would also help with the 'harshness' which might also resemble ringing. I believe I'll do both mods along with the xover repairs and mechanical mods to mine. What xovers/mods are you using? Will the P-traps work with any mod of xover or is it specific to whichever xover you have?

Thanks

Michael

[seti]

I finally bought some rope caulk this week to do my belles but i am nervous about talking out the horn is it possible to do without pulling it out ?