New Horns and Tophat Grills on Khorns & LaScala Clone

[KdAgain]

I am going to try going two way with Paudio PH-4525 horns with BMD-750 drivers in our 1958 Klipshorns and LaScala Clone Center.I need to work out the mounting of the new horns and also how best to make a new grill for the LS and possibly new ones for the Khorns. I bought some new black grill cloth from Bob Crites and want to use it on all three tophats.

Here's a photo of the upper section of one of our Khorns. (Hope this photo posting works as it doesn't show in my 'Compose'.)

I had origionally planned to mount the new horns from the front about an inch and a half back from the front of the cabinet. It would be mounted on a new motorboard with the horn flange being on the motorboard front. This would allow the same grills to be used as on the Khorns.

A few questions have arisen:

1. Is it important to have the horn front as close as possible to the cabinet front, or does that matter?

2. Do the newer Khorns (post 1958) use a different grill design than mine? Mine have small vertical wood strips that may block some sound.

3. Does anybody have a photo of the newer grills from the inside?

Thanks very much.

Rod

[Rudy81]

Here is my La Scala with the PH-4525 and the BM-D750

[Rudy81]

The newer grille designs do not include those vertical strips you show on yours. The newer grillles have a solid piece of lumber along the front, with holes cut for the mid and tweeter horns. I made my own front to allow the PH-4525 to fit centered on the speaker. I will look for some pictures of that project.

[KdAgain]

The newer grille designs do not include

those vertical strips you show on yours. The newer grillles have a solid

piece of lumber along the front, with holes cut for the mid and tweeter

horns. I made my own front to allow the PH-4525 to fit centered on the

speaker. I will look for some pictures of that project.

Hi Rudy,

I was hoping you would chime in here. Thanks!

Good to know about the new grills being a solid piece of wood. As tight as the 4525s sit in the tophat there wont be much wood left top and bottom though.

For our LS clone I'm making a separate top hat that is similar to the Khorn top hats. We want a grill on it and hope to have it be much like the Khorn grill.

Hope you can find some photos of how you did these horns and grills in your Khorns.

Thanks again,

Rod

[Rudy81]

Rod, here is a picture of the new horn mounted on a DIY motorboard before I added the grille cloth. The horn will just fit and allow for installation of the cloth....at least it did on my model.

Edit: IIRC, I used 3/4" BB for the motorboard, and cut to size 2x4 lumber to make up the side vertical pieces, which is where the motorboard screws into. I painted mine black since my cloth was black.

[Rudy81]

Here is what the back looks like with the driver mounted.

[Rudy81]

For illustration purposes, here is my DIY DBB build. I made the top hat section a little taller to give me a little more room for the horns. I think with a little work you should not have a problem making a motorboard that will accomodate the horn and allow for 100% cloth coverage. I have gotten away from covering the horns with cloth in the search for best sound I can possibly get.

[KdAgain]

Thanks for the helpful photos and descriptions Rudy. Brings up more questions.

1. When you put the grill on the Khorn did you just tack (or staple?) it across the front? Seems that the horns being front mounted would bulget the cloth out.

2. Did you wrap the cloth around the sides?

3. How would you remove a horn if you wanted to?

4. I'm wondering if the newer Khorns mount the horns from the rear of the motorboard. Then at least they could be removed.

5. If 4 above is true does the rear mounting have any negative affects on the SQ?

Enough for now!

Thanks,

Rod

On edit and after rereading your post perhaps even on the Khorn you did not cover the horn with cloth. If so I still wonder how the new Khorns do it?

Rod

[Rudy81]

1. I mounted the horn so it was not behind the cloth. But, since you want to do that, you may have to use a router and create a rabitt for the horn flange to sit in. Thus, making a flush surface for the cloth.

2. The way I mounted it, it was just a matter of removing the screws. If you mount the cloth on top fo the horn, that is a whole other problem.

4. Yes, the standard Khorns just have the hole and the horn is screwed into the motorboard from behind, making it easy to remove.

5. I have read some articles stating that the 3/4" lip does affect the sound, but how much, I don't know.

It is going to be tricky to 'hide' the horn and still be able to easily remove it, unless you mount it flush to the back of the motorboard.

Another option, is to make some giant 'Z' brackets for the horn, like Klipsch did for the tweeters so that it can mount from behind and yet be flush with the front of the motorboard. With a little ingenuity, that may be the way to go.

[KdAgain]

Thanks again Rudy for all your information. Looks like I'll have to get real creative to mount it behid the grill and not have it too far back in the top hat.

When I get my MiniDSP for Active Crossover and EQ I'll do some experimenting before making anything final. I really am curious if mounting behind the motorboard has any detrimental affects. Surprised Klipsch woull do it if it's an issue, but they are in business to make money and have to keep things as simple as they can.

Hope you are having a great weekend!

Rod

[Rudy81]

Well, Klipsch started putting Z brackets on their tweeters somewhere along the way. That should say something.....at least where HF is concerned.

[Rudy81]

Found this picture of the interior of a stock top hat. The tweeter has Z brackets.

[KdAgain]

Found this picture of the interior of a stock top hat. The tweeter has Z brackets.

Thanks Rudy,

A little difficult to see how the Z bracket is working but I think I get the idea. I believe I've figured out how to do the same thing with wood. It will get the horn flush with the front of the motorboard but be removable from the rear. Then the grill will cover the whole motorboard and wrap around the sides to look like the original one.

I also want to leave room for a tweeter in each one just in case I want to use one later. Since the PH4525 horn takes up almost all the vertical space available the tweeter will probably be mounted to one side and vertical. I'm trying to decide which side to put it on. My inclination would be to put it on the right side of the left speaker and vice versa for the right speaker. This would put it furthest away from any side wall reflections. Any thoughts on that?

Rod

[Rudy81]

Rod, sounds like you have it down. Don't worry about which side to put the tweeter on. Since the motorboard is removeable, you can always swap them from one speaker to the other and now the tweeter is on the other side. I ran some listening tests that way to see which I preferred when I was using a three way setup with Trachorns.

[Rudy81]

http://forums.klipsch.com/forums/p/68519/669320.aspx

In the above thread, Bob shows a picture of a tweeter and the Z brackets.

[KdAgain]

http://forums.klipsch.com/forums/p/68519/669320.aspx

In the above thread, Bob shows a picture of a tweeter and the Z brackets.

Well that sure shows them! Thanks. Guess Klipsch doesn't feel it important to do the same thing with the mid horn - or they can't be bothered.

And thanks also for the idea of swapping motorboards between speakers. After you wrote that it occurred to me that I could also just put them upside down within the same cabinet to reverse.

Rod