Sealing the backs of KHorns to walls....

[rockbobmel]

I was reading the Dope files and there was some mention (wording unsure) about using a rubber gasket of sorts to seal the backs to the walls. I was thinking of getting some rubber backed carpet, or stair step skid rubbers and stapling them to the back of the horns, pushing them back so they seal(somewhat) the enclosure against the wall. Kinda like a door sweep would. My horns are toed out so the seals would have to lay at an angle to be about even. Not near ideal, but it would prevent the lows from rising behind the speaker to the upper portion of the room. Am I making sense? It is hard to describe what I invision. Is it true that at that stage of the flare/mouth the pressure is very slight because it dispurses as it leaves the horn?

Thanks, Bob

[michael hurd]

There are many materials that you could use to make a seal, even garage door weatherstripping ( stuff that seals the bottom ). It all depends on what you can find locally, and your imagination.

You have toed out the klipschorns? If you are not using a false corner, that the speakers are sealed against, then you will most likely suffer a loss of spl in the 250 - 400hz range.

[rockbobmel]

Yeah, I am getting kick drum to pipe organ lows, but they seem not as present as they should be I am planning false corners this spring.

[PrestonTom]

There have been a number of threads on this topic. The general consensus is that you will get an improvement. Common to many of the threads is a recommendation to use Pipe foam insulation (closed cell). It is fairly cheap and easy work with. The stuff that is 1.5" can be used on the back verticals and 3/4" (split in two, lengthwise) along the horizontals. This should fill in any gaps, although in your particular install there may be some other architectual issues. Have a look at some of the photos.

Good luck,

-Tom

[stan krajewski]

First, I don't own KHorns.

However. Aren't the adjacent back and side walls part of the KHorn design/theory? If so then they (walls) are part of the speaker and if you accept that premise then being sealed to those walls and having really solid walls must surely improve the sound.

Seems like a no-brainer.

[3dzapper]

Bob, You are correct. Don't use that clear stair tread vinyl though. I found that it tended to warp when I used it in the seventies. The best I have found is the heavy black rubber mats designed for commercial use. All you need is a piece about 4X3' cut in half. Properly sealed, you may find that you don't need the false corners even with a little toe in.

Another idea is to put something on the bottom of the top section where it is not visable to seal and complete the horn. I use pieces of egg crate foam there between the top of the bass bin and the wall.

[rockbobmel]

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On 3/29/2005 10:05:22 AM 3dzapper wrote:

Bob, You are correct. Don't use that clear stair tread vinyl though. I found that it tended to warp when I used it in the seventies. The best I have found is the heavy black rubber mats designed for commercial use. All you need is a piece about 4X3' cut in half. Properly sealed, you may find that you don't need the false corners even with a little toe in.

Another idea is to put something on the bottom of the top section where it is not visable to seal and complete the horn. I use pieces of egg crate foam there between the top of the bass bin and the wall.

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ALRIGHT!! Thanks.. I have some wierd geometry back there. In addition to the angles, I have the horns on a 1" block toward the back to angle them down toward my head, so the backs need some "flap engineering". Big Time.!!

[rockbobmel]

I got a few rubber backed floormats and rolled them up, inside out, and stacked them vertically behind the back center piece. I played around with them (with the tophat off) till I got them to seal each side with thier own pressure. They were almost long enough for the whole vertical but I pulled them up so as to be even with the top of the bass bin. I got a bigger one and layed it across the top, into the corner then measured 13" from the front and cut it off there. The tophat sits on it (a little tilted down), but the front looks normal. The mat rests on top of the vertical piece and splays to the walls to make a horizontal seal. The speakers are toed toward the sweet spot so the sidewall and back wall are not even. The bass sounds more focused now (I wish I could measure the freq. resp.) maybe the 2nd and 3rd harmonics are more audible, and I am going to listen for a while before I go and build false corners. I am a limited tweaker and usually want a simple remedy, but for now (at least this week) I'll leave them. They really sound ALIVE!!