Rope Caulking Works!

[marems]

i have been thinking about putting some kind of damping material on my Heresy II mid horn, not because of harshness though. i can feel some substantial vibrations when i touch the horn, especially the center channel heresy. i view it more as a weak point in the cabinet that could use some more solidity. i do detect a resonant quality from time to time on certain voices and suspect it is the plastic horn body being stimulated by the lower midrange frequencies. i would like to hear others thoughts on this. thanks

Vindeville, I get the same sounds from my plastic horns as well... I rope caulked my KLF-30's horns, and that did a great job! It seems like eveything is alot smoother and clearer! I just got some of that Cascade Damping spray from Parts Express. So now my next tweek is to order another pair of horns for my CF-4's and try out the damping spray on those.

[BS Button]

I will keep repeating this so all concerned will perhaps see it. I bought a pair of Heresys that had been someone had rope-caulked many years earlier. It was a pretty extreme case where the guy for some reason put that nasty stuff all over the tweeter, midrange horn and driver, the crossover and the woofer. The junk had been in there long enough that the rope-caulk had started to de-compose and the oil had dripped out of it and was all over the cabinet and even some of it on the woofer cone. When I tried to remove it, the sorry stuff had hardened and took all the paint off the horn and all other parts it had been applied to.

Anyway, now if I have a ringing problem with a horn, I tighten up the screws holding the horn to the motor board real good.

Bob Crites

Seems like I get burned for coming down on this side, as well, although I think that the Altec horns, need something.

[BEC]

Button

I am all for fixing problems where problems exist.  I think in most cases on these horns, Brennen is right and Berenek's Law is controlling.  All of us use a very sophisticated equalizer that is between our ears.  Trouble is that we have little control of that equalizer.  We think things should sound better after a break-in and that internal equalizer adjusts to convince us we thought right.  Somebody has a horn that rings and the equalizer convinces us that our horn rings too.  Whatever he did to fix his, our equalizer will make sure that same thing will fix ours. 

And, you are right about the Altec horns.  They need something all right.  Make better bells than horns.

Bob

 

[3dzapper]

"And, you are right about the Altec horns. They need something all right. Make better bells than horns."

Don't be afraid to tell us how you really feel Bob.-)

Rick

[colterphoto1]

I once had a nasty resonance coming from a midrange plastic horn in a Cornscala. Only heard it with some heavy bass notes on one recording. I used a signal generator to find the frequency, (about 100 hz in this case) and was able to find that the resonance was coming from the flange of the horn where it attached to the motor board. I tightened it up enough to stop that and was done with it. I later put a gasket between the plastic horn and the wooden motor board and found that with the gasket, it did not even have to be that tight any more.

Bob Crites

That's a good thought Bob, I'll try that when I redo my CW's. Quicker than a caulk job too.

M

[IB Slammin]

"And, you are right about the Altec horns. They need something all right. Make better bells than horns."

Don't be afraid to tell us how you really feel Bob.-)

Rick

Rick,

Contrary Old Rascal isn't he.[|-)]

tc

[HarryO]

Bob, as you know I've been experimenting with quite a few horn/motorboard combinations lately. Some of the horns I've tried have need for dampening. I have been using the 3M brand of grey 1/2" double back tape and giving the horn a quick wrap. It works well, makes no mess at all, and removes easily if desired. It's available at most automotive parts supply stores.

Send me a pair of the new horns when they show up. Tomorrow? I hope.

HarryO

[Islander]

Making sure the squawker horn is tightly screwed to the motorboard makes sense, but it's easy to strip the holes in the plywood. One of my La Scalas came with two stripped holes with chalk arrows pointing to the holes, I suppose to caution the final assembler not to overdo it. It was easy to repair the holes by gluing in a piece from a disposable chopstick cut to the size of the hole, then drilling a pilot hole a little smaller than the screw's minor diameter.

My furniture refinisher buddy suggests that when tightening a screw into wood, snug plus a quarter-turn is as tight as you should go.

[johnyholiday]

One could damp ones own Body.....to the point of delirious delirium.....{straight line for fini}

The human body is a structure,

Body parts have mass and stiffness, and hence natural periods of vibration. These parts can resonate with a forcing function, and become highly perceptible and annoying. Humans are particularly sensitive to vibrations in the range of 3 to 8 Hz

[tidmack]

I've used DynaMat in the past with good results. . .at least to me. But it sounds like from what I'm reading that the whole horn doesn't need to be wrapped to make the ringing stop. If I just wrap the horn a couple of times around, should that be enough? Thanks.

Jeff

[BEC]

After the Dynamat has been on for awhile, it is not really removable. It either takes the paint off or leaves a tar covering over the paint.  

Bob

[BS Button]

After the Dynamat has been on for awhile, it is not really removable. It either takes the paint off or leaves a tar covering over the paint.

Bob

Bob,

If you'll recall, you sold me a pair of 400's with the Dynamat covering both. I spent the next two weeks, little bit by little bit removing the Dynamat, then I did some grinding and light sanding to remove the casting flash from 1974 model year. I had them sandblasted the next week and sold them unfinished for nearly $320 bucks. But, the Dynamat was extremely difficult to remove...it's like tar with adhesive. Point is that I don't think that I could've sold them for that much since they had the Dynamat on there. It's relatively permanent.

[BEC]

Button,

I have another set of K-400 horns with that nasty Dynamat all over them now. I am thinking of sending them to you since you are experienced at getting that stuff off of them.  Would that be all right?

Bob

[BS Button]

Button,

I have another set of K-400 horns with that nasty Dynamat all over them now. I am thinking of sending them to you since you are experienced at getting that stuff off of them. Would that be all right?

Bob

Why doesn't somebody that wants Dynamat horns buy them, or trade you out for a clean pair?

BS

[Dylanl]

Button

I am all for fixing problems where problems exist. I think in most cases on these horns, Brennen is right and Berenek's Law is controlling. All of us use a very sophisticated equalizer that is between our ears. Trouble is that we have little control of that equalizer. We think things should sound better after a break-in and that internal equalizer adjusts to convince us we thought right. Somebody has a horn that rings and the equalizer convinces us that our horn rings too. Whatever he did to fix his, our equalizer will make sure that same thing will fix ours.

And, you are right about the Altec horns. They need something all right. Make better bells than horns.

Bob

Bob, you have to be kidding right? The Altec horn is by far superior. Thats why you see so many here using the 511 to repalce the existing horn. Believe me the 511 is by all means the best but it's better than whats there. I certainly wouldn't call them bells?

[TBrennan]

Dylan, ole Bob reeled you in like a big fat channel cat. Or a walleye if you prefer. ;-)

[BEC]

I tried the 511 and compared it to a K400,  I was not impressed.

Bob

[BS Button]

Dylan, ole Bob reeled you in like a big fat channel cat. Or a walleye if you prefer. ;-)

Kinda like this?

[IB Slammin]

Dylani,

No, he is not kidding. Bob and me have been gouging one another over this subject for several years. I have had the opportunity to listen to enough of his replacement parts, mods, and his personal stock at B&K labs to say, "the old coot ain't deaf". We agree on most things.

I hope that I haven't said that I think the K-400 is a POS, having had only a limited time to A/B them with a 511b crossed at 400hz. If I haven't said that I think the K-500,K-600, and K-700 sound terrible compared to a 511b, then let me say it NOW.

It is my belief that Berenk's law applies only to those who mod, and think that every mod is an improvement. To make a blanket statement implying that all DIY tweekers lack objectivity,....... is a bit of a stretch.

I have asked BEC what he dislikes about the 511, and the answer is always......."they should be used as trash cans, ash trays, or heads for a Yugo".......

tc

[BEC]

Dylani, 

No, he is not kidding. Bob and me have been gouging one another over this subject for several years. I have had the opportunity to listen to enough of his replacement parts, mods, and his personal stock at B&K labs to say, "the old coot ain't deaf". We agree on most things.

I hope that I haven't said that I think the K-400 is a POS, having had only a limited time to A/B them with a 511b crossed at 400hz.    If I haven't said that I think the K-500,K-600, and K-700 sound terrible compared to a 511b, then let me say it NOW.

It is my belief that Berenk's law applies only to those who mod, and think that every mod is an improvement. To make a blanket statement implying that all DIY tweekers lack objectivity,....... is a bit of a stretch.

I have asked BEC what he dislikes about the 511, and the answer is always......."they should be used as trash cans, ash trays, or heads for a Yugo".......

tc

 

 

TC,

I would agree with most everything you said there.  I think the 511 is ahead of the K-500, 600 and 700.  Just don't find it to be ahead of the K-400.  In fact, take a drive over to former forum member (whose name we won't mention here to maintain that holiday spirit) website and look at comparison he did of the K-400, 5llB.  Where is the 511B better?

So, anyway, I don't dislike the 511, just like the K400 better.  And I said that metal belongs on an Escort.  It is too good for Yugo.

Bob