Hepner midrange horns?

[Herc]

Hello forum members, I'm new here and have been in the background reading the info on here. Its great help!

I have come across some older midrange horns (in great shape)supposedly made by Hepner before he past on and Klipsch bought them out(?)They are 4" X 10.5".

I am in the process of making K horn clones and am wondering if the mid drivers are worth using in them? the system of course will have a seperate tweeter horn.

Thanks.

Tony

[justin_tx_16]

quote:

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Originally posted by Herc:

Hello forum members, I'm new here and have been in the background reading the info on here. Its great help!

I have come across some older midrange horns (in great shape)supposedly made by Hepner before he past on and Klipsch bought them out(?)They are 4" X 10.5".

I am in the process of making K horn clones and am wondering if the mid drivers are worth using in them? the system of course will have a seperate tweeter horn.

Thanks.

Tony

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you are making K-Horn clones?! that is super sweet! do you have plans for them or how is this working? please let me know, i am in the process of building some University Horns and making some K-Horns would be awesome.

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-justin

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[esker]

Welcome!

I don't know about your particular horns, but no Heppner horn I ever saw was anywhere near the quality you want if you're going to the trouble to make Klipschorn clones. At 4" X 10.5", they won't play at a low enough frequency to get down to your crossover point with the woofer, either.

Keep looking - there's some really fine stuff out there that will do a better job for you. The place to find out about parts other than Klipsch is www.audioasylum.com/forums/HUG/bbs.html - you can't believe everything you read there, but it'll show you where to look to find things out.

Hope you have access to real Klipsch (Heritage) for regular reality checks as you go.

Good luck with your project.

[djk]

The old Hepner 4 X 10 HF horn will work down to 800hz with an 18dB/oct crossover. I made a bunch of 'poor man's' Cornwalls with them and they measured and sounded quite nice. The original 2" VC Cornwall midrange driver has 4 X the diaphragm area, so of course it has less distortion. If you are really going through all the trouble of building a Klipschorn bottom, you would be best advised to budget for appropriate drivers.

[Herc]

Ok so I will not be using the hepner drivers.This is what I have now, JBL 2225H woofers, JBL 2416H CD and horns. Any suggestions on a midrange? I see there are some JBL 2123H on ebay.I would like to add mids to the k horns to "fill" slight dead spot in front of the horns.

Do members have preferrence over horns or cones?

PS-there is a set of K horns 4 sale in my area for $600 US !!!! But I am in northern BC Canada. I havent seen or talked to owner yet.

[esker]

First, get cracking on those $600 horns. That's a great price if they're real Klipsch in working condition.

Don't know about any 2416H JBL driver. Could you mean the 2426H? With most 1" JBL compression drivers, you'd have to cross over at 800Hz or above. Same frequency as the Heppner, but with oh so different results! If you don't use more than a watt or two, you might reduce the crossover a little, but you'd probably need a bigger horn. Which horn do you have?

Even with the 800Hz crossover you might make a go of a 2-way LaScala. The K-horn woofer really should be crossed over below 500Hz. The 2225 might work nicely for you in either of those bass horns. With different bass drivers, you might even make a stab at a Jubilee!

You could use the 2123H to fill between the corner horn and the compression driver. But PLEASE put it in a horn!

JBL professional drivers are wonderful - especially the stuff they made before they had to make them bulletproof against kilowatt amplifiers. Integrating them into a whole will be the hard part. In the end, with lots of work and good test equipment, you may end up with something nice, but they won't be Klipschorns. Good luck.

Mark

P.S. Haven't you picked up those Klipschorns yet?

[Herc]

Thanks Esker for the help. The 2416H are a threaded throut verson of the 2426H (same specs, same coil).Not sure about the horns one says on it JBL MI 291, with some checking I see that the MI 291 was a CD and horn combination offered by JBL.They measure 15" X 5 1/4". The reason I asked about CD versus cone was this: as sound is movement of air, how effective is a small CD diaphrahm combared to a larger cone transducer? Or is this why we use horns???? Just seems to me you dont get the same "punch" as a cone (especially lower frequencies. Excuse my ignorance as Im new to horns! But Ive heard enough to make me want to build some.

About those $600 K horns, Im tempted ,but have spent enough to obtain the drivers and I am capable of building the horns and would like to make improvements. Guess Im a fool for punishment!!

Thanks again.

[Herc]

thats "throat" not "throut" ? where did that conme from???

[esker]

So you want to make improvements on the Klipschorn? First you'll need about fifty years of education and experience. Build an anechoic chamber with a revolving corner. Spend maybe half a million on test equipment. Get samples of scores of drivers from dozens of manufacturers. Test them all for frequency response, polar response, transient response, distortion, power handling, reliability, etc. The second week you can start building prototypes.

Pardon my sarcasm, but I've been there. My DIY corner horns, over the years, had drivers from JBL, Electro-Voice, Stephens, and Western Electric. The top horns have been Ben Drisko wood, cast aluminum exponential, radial, cast non-resonant tractrix. They all sounded good. The Klipschorns blew them away every time. So did the Heresies, for that matter.

I tinker with the things because I enjoy it. If that's your cup of tea, more power to you and welcome to the club!

Why are horns better than cones? That's a long story, but basically, properly built horns are more efficient and have less distortion. The sound is lightning fast - imagine the 2416 driver with the mass of a 2" dome but with a 15" X 5 1/4" surface area. Now imagine the 15" woofer with a 2000-odd square inch surface area. That's what the horns do. Now that's punch! Horn speakers move a lot of air while the drivers are hardly moving at all. That's why they sound so effortless.

By the way, CD horns - in this case CD probably stands for constant directivity. That means they're designed to have a constant polar response, but with falling treble. You'll need an equalizer to get flat frequency response. The explanation for this is in the JBL Professional Sound System Design Manual at www.jblpro.com/pages/tech_lib.htm

Have fun with this project. I promise it will keep you occupied. Check out the archives at the High Efficiency Speaker Asylum. Bruce Edgar really knows his stuff, so look for his posts.

Enjoy!

[Herc]

Mark, ok maybe improve was the wrong choice of words. More like "tweaking" using the knowledge of forum members.With the K horns being as old as they are and so many talented owners I'd like to incorporate ideas that they have come across into the clones.To bring the k horns more up to date with todays audio advancements. For example- has anyone filled in the voids within the horns with acoustical batten and what if any effect did it have? Would this deaden the sound?

I used the term CD as I thought it meant compression driver.

But, thats why Im here to learn more!

Thanks

[esker]

Pardon my misunderstanding on the CD. You'll need to find out more about that horn, since a lot of JBL's recent stuff is constant directivity (bi-radial). Or else you can make a tractrix.

One of the first things you'll need to decide is whether you want a whole room full of decent stereo (PWK's goal with corners-plus-center three-channel stereo) or a sweet spot with intense stereo imaging. In other words, is the system to be for company, or for yourself alone?

The constant directivity horn would tend to cover the whole room evenly, but require equalization. A straight tractrix would give you flatter frequency response without EQ, but only in the sweet spot. This is just an example of the choices you'll have to make. No one can decide for you.

If you want to entertain, use the Klipsch approach and keep it in the corners.

If you're looking for a personal sweet spot, go with the Bruce Edgar type of system with main speakers out in the room, plus subwoofers (possibly corner horns, in your case).

It's up to you.

By filling the voids, do you mean stuffing the compression chamber? Some have tried it, and liked the results they got with less-than-ideal drivers. PWK didn't, and that wasn't because he didn't think of it. He told me it was because he wanted a pure capacitance to match the reactance of the horn. He didn't really believe in resistive damping. He preferred radiation resistance.

If you mean stuffing the horn, forget about it. If you mean that prism-shaped space in the corner behind the speaker, sealing that off isn't a bad idea.

[djk]

"So you want to make improvements on the Klipschorn? First you'll need about fifty years of education and experience. Build an anechoic chamber with a revolving corner. Spend maybe half a million on test equipment. Get samples of scores of drivers from dozens of manufacturers. Test them all for frequency response, polar response, transient response, distortion, power handling, reliability, etc. The second week you can start building prototypes." Uhh, Klipsch built the chamber in about 1980. When PWK designed and built the first units he did not even own a microphone.

[esker]

PWK said his first unit "sounded like hell."

The Klipschorn was developed over time, and that development was guided by testing and measurement. PWK believed in testing and measurement, and used a lot of test equipment over the years. He was fond of quoting Dr Irving Gardner: "You can't make what you can't measure because you don't know when you've got it made."

What you say is true. Many of those things I mentioned that he did in the pursuit of excellence did not occur before the initial release.

The point I was trying to make is that you can't just walk in off the street and do better than the man who devoted his life to the effort.

If we wish to stand on the shoulders of giants, we must first make the climb.

[Herc]

Sorry if I stepped on some toes by my statement about improvements. Not my intention. I realize what the K horns are and what status they evoke.

But like you said they started with an idea and it grew from there as most great ideas do.Along the way someone with a different way of looking at things injects their thoughts on a different angle.

My specialty is cabintery and I take pride it what I am capable of doing.And I consider myself inventive and very curious.

I am far from being an expert but I have some ideas that Id like to see if they work, thats all. And Im sure my ideas have been attempted by someone already. All of us are here to learn from this forum and Im greatful for it.

Esker- by filling in the "voids" I am referring to the unused spaces of the horn -behind each horn fold- (dead air chambers )another example is the horizontal 2 sided "ramp" directly in front of the woofer. Hope that makes sense.

Thanks again.

[esker]

Sure, Herc. Didn't mean to get touchy. Just want to convey that it ain't as easy as it looks.

There are lots of things you can do when you're building for yourself and don't have to worry about shipping and such. Filling in those voids is a great idea. Edgar followers often use expanding aerosol foam in that sort of space. Others use sand, which is removable. Concrete would probably do the job. You'd have to consider the effect of the weight, and that it might make the structure sag over time. I've heard of foam expanding so strongly as to blow the sides off the box, so pay attention.

The space outside the X behind the front panel usually needs be open to the compression chamber. The production unit has been that way for many years, but some plans may not show that. This is because the K-33-E woofer requires the extra volume. It's possible your driver might not, but that's not easy to determine until you get the box built and check the resonance frequency with the woofer sealed in the chamber.

Bruce Edgar has suggested making the 45-degree reflectors larger at the throat and at the first turn at the top and bottom of the front panel. This us supposed to extend the upper frequency limit, which would be a big help with your compression driver. I can't remember his exact words, but if you visualize the reflectors as mirrors rather than waveguides you'll have the idea. I think it's in his 1990 "Speaker Builder" article called "The Show Horn." Bruce will send you a copy for a very reasonable price, or you can get the entire year of the magazine from www.audioxpress.com

It's hard to say how much these mods will affect your work. Haven't tried them - just pointing you in a direction for research.

You never know how significant a change will be till you try it. Lots of members here will suggest damping the squawker horn to reduce any metallic ringing. It might work for them, but when I rap on my squawker, all I can hear is the reverberation from the wood of the woofer horn.

I find the woofer horn is not as acoustically dead as I would like. The sound is pleasing, but an entirely non-resonant cabinet would be theoretically preferable. You might experiment with concrete to see if you can come up with an acoustically inert recipe. This will be extremely heavy, of course, but might not be a problem for you as you will not be shipping worldwide. But since you are a cabinet maker, that might go against the grain...

This message has been edited by esker on 06-15-2002 at 07:18 PM