(k)horn in a 4-dimensional corner?

[Soeren Basboell]

In 'my' room in our house in France one of the walls goes down to the floor in an angle of 45 degrees.

That space can not be used for much, but since we made that restauration of the old house, I have thought of theese corners with a room angle of Pi/4.

So now I am obscessed with the idea of designing a (k)horn for a room angle of 45deg allthough it is doubtful if I will ever realise it.

Søren

[Soeren Basboell]

I am a little disappointed that nobody seems to be interested in this problem or solution.

In this forum we normally have a set of khorns, how do we create two corners?

Here I have two corners twice as efficient as normal corners, how should the horns be designed in order to benefit from it?

Søren

[artto]

You shouldn't be disappointed.

The "problem" is somewhat different than what you percieve and how you describe it. The Klipschorn is already designed for 1/8 space. This essentially makes the speaker perform as if it were eight times larger than what it actually is.

There is an old Klipsch advertisement from the 60's or early 70's that tries to show this although I doubt few people actually understand the concept or what is happening.

I'll try to explain. You say you have "two corners", and, that these corners are "twice as effiecient as normal corners".

First, I'm going to have to make some assumptions as to what you mean by "two corners" (I hate making assumptions). I think what you mean is that since you have a 45 degree corner instead of 90 degrees, that you can make "two corners" out of it, and thereby this would somehow increase the effieciency. (?)

This is not true. The 90 degree corner of the walls is simply an extension of the exponential flare of the bass horn, adding the extra length, and increasing the mouth size to extend the frequency response lower. AND, it is also, the floor, which is part of this system. It is a tridedral corner = 1/8 space. Any speaker can benefit from this. What is different with the Khorn is that a horn is able to occupy that space and take advantage of 1/8 space to the maximum degree (no pun intended).

What you are attempting describe (as far as I can tell) are two 1/4 space corners sort of super imposed somehow in four dimensions. Or, you are misintrepreting how space boundary relationships influence (reinforce) speaker low frequency performance.

I've uploaded a page from an old Klipsch brochure which hopefully will shed some light on how this works. Free space would be the first picture (fig.6), but without the mirror. The first picture (fig.6) at the top of the page shows a light bulb against a mirror (ie:wall). This is 1/2 space. The mirror divides the space as a wall would, reflecting (reinforcing) the sound that would have gone in the opposite direction back into the same space the speaker (light bulb) is in.

In the third, final image (fig.8), notice the "eight" Khorn images - one is the actual speaker, plus the other seven images, both behind (around) and below the speaker. That is the result of 1/8 space, a trihedral corner. Click on the image to enlarge.

[Soeren Basboell]

Thanks for the answer, but I my approach differs a little bit.

My main argument is that every time we reduce the radiation angle by a factor 2 the radiation resistance goes up by a factor 2. Thus:

Free air - 4Pi

Traditional corner - Pi/2

'45' corner - Pi/4

The idea is that in a '45' corner the radiation resistance is 16 times greater than i free air where it is 'only' 8 times greater in a normal corner.

In other words, if such a horn can be made, it could either go a little octave deeper for the size of a khorn, or it could be considerably smaller for the same low frequency performance.

I am personally convinced that if PWK had lived in such a room for some time, his thoughts would go in the same direction.

Søren

[Soeren Basboell]

Another thought, as the distance between the two corners is relatively small, 3 meters I guess, I am tempted do design it a little inspired by JBL Paragon in the sense that it could be made as one stereo speaker but it will be linked to that room.

Anyway it is only an idea in my head, trying to transform a drawback into an advantage.

Do the line separation (enter) work? I am using Linux.

Søren

[JJkizak]

Soeren;

I was in Kulusuk for about 6 years on and off. You can move the K-horns anyware except as you get further away from the 90 degree corner they become less efficient and loose a ton of bass. Your room should be at least 16 to 18 feet but the optimum is about 25 feet with a center channel. They will work better in a 45 degree corner than no corner at all.

JJK

[WMcD]

It sounds like you have a room under a pitched roof and it comes down to floor level. And is correct that the adjacent walls on either side are vertical?

The issue, it seems, is that in a normal trihedral corner, there is left-right symetry as we look, in a horizontal plane, into the corner. That means it is possible to make a bass horn with left-right symmetry overall to fit into the corner. The mouth (or mouths) are symetric. It seems like that is not possible in your situation. That is because looking into the corner you have the roof on one side and the vertical wall on the other.

One additional thing is with the usual bass horn design is that the last part of the horn flare faces forward . . exactly how to do this in your situation is challenging, or can't be accomplished.

Making a folded horn to fit snuggly into your corners and face directly out into the room seems impossible.

Some people have used a LaScala bass bin and pointed it into a normal corner. Maybe that would work for you.

The other possiblity is a straight bass horn terminating at the corner. Many years ago I read a description of making a straight bass horn for a corner with just one piece of plywood for the horn section. Hard to describe. Imagine building a four sided pyramid with the base as the mouth big end) and the vertex as the throat (small end). That is a conical horn in effect.

Looking from the top, you draw lines from the center of the base to the points of the base. Like an X. Now you can see how one of the four sections will fit into a 90 degree corner and fire toward the floor. If you had to, you could design a bass horn fitting into the wedge formed by the roofline. Then you have to make a cabinet for the driver with a back chamber. Then you'll have to put the mid and tweeter in the corner somehow.

That is all I can think of tonight.

Wm McD

[artto]

Can you post a picture of the room and corners? Thanks

[Soeren Basboell]

JJK,

funny, we might have met in Kulusuk without knowing each other.

My question is not about how to get the optimum performance from a set of khorns. I have such at set and a laScala here in Tasiilaq where I live, 20km from Kulusuk.

Actually I did not really ask a question, but if there is a question, then it is of a mathematical nature:

Can it be proved that there is or is not an existing mathematical solution to the problem?

And if there is a mathematical solution to the problem, is there an elegant solution to the foldings which can be realized in real life (it does not have to be easy)?

William is closest to understand the problem.

I have no photos of the room, and I will first go to France in september.

The thread was mostly started as a philosophical reflection over what would PWK have done if he had had such a room, i guess that he would have gone for the maximal radiation resistance.

A khorn was impossible before PWK made it...

Søren

[Soeren Basboell]

I think that I now have found a qualitative solution to the problem. First, the situation is as William described it, which means that the roof is going down to the floor in an angle of 45deg, and the end walls are vertical.

If we look at a Jubilee in a normal position there is a vertical symmetri plane and the corner walls would make an angle of 45deg to that plane.

Now we could reduce that angle to 22.5deg and change all the elements correspondently. It would probably be necessary to use 4 x 6.5" speakers in order to get the right flare in the beginning of the horn, delicate mounting, but probably possible.

Then the whole thing is turned 90deg and placed on the floor with some spacers in respect to the horizontal symmetry.

The whole thing has to be (re)calculated, but that is a minor problem.

Søren

[mungkiman]

If you are working on theoretical designs, have fun.

If you are looking for practical solutions that would enable you to use existing Klipschorns, you might consider building a "knee" wall. This would intersect the ceiling (roof) plane, vertically, with enough room for a Klipschorn to sit on the room side of the wall. This could be a wall that ran the full width of the space, or only wide enough for the horns, which might leave enough space to build-in shelves for equipment.

If all else fails, talk to Greg...

[Soeren Basboell]

I do not know why some of you think that the solution to the problem should involve a khorn, maybe it was because I wrote a '(k)horn in a 4-dimensional corner', but that was only intended as a 'khorn inspired' horn. We all agree that a khorn is an ingenious solution for a 3-dimensional corner, but it is not for a Pi/4 corner.

The question is: How should a horn be designed being optimized for a Pi/4 corner?

I find that there in life is nothing more practical than a really good theory, so I am starting there.

Søren