Folded horns for pro use

[fitzmauricew]

How curious that the company that built its reputation with folded horns doesn't make them for pro useage as PA mains. Perhaps because its assumed (wrongfully so) in the industry that folded horns are only useful as subs?

So, on to my real question- two questions,really. First,can you produce a folded horn loaded with a single twelve having 108dB/watt sensitivity from 100Hz to 5KHz? Assuming the answer is no, would you like to? Because I have done exactly that. I'd very much like to talk with you about it.Thanks.

[tpg]

I realize I am out of my league in the Pro-Audio section, but where did you find a driver with that high of sensitivity?

[fitzmauricew]

Its not the driver.its the cabinet. The driver is a stock EVM 12l with nominal 100dB SPL. Put it in the horn I designed and it works as stated.

[tpg]

Oh... like I said... don't know much about that stuff.

[fitzmauricew]

1500 hits and you don't know about folded horns? The folded horn is what made Klipsch- too bad they have gone away from what made them great and now they make T/S boxes just like a hundred other companies. Klipsch may have (temporarily?) given up on the folded horn, but I haven't. My latest design- a small stage vocal monitor,driven by a five inch mid-bass. Same size as a 'Hot-Spot'- but with 104dB sensitivity. A folded horn in 3/4 of a cubic foot? Believe it.

But back to you- have you read Paul Klipsch's biography? Its as good a place as any to find out about the first 50 years of folded horn technology. Someday you'll be able to read my biography to learn about the next 50.

[tpg]

Well, most of my posts came from the ProMedia forums... I do know of the folded horn, though- in the K-horn. I am familiar with its use and design, but I do realize that many others that frequent this forum know much more about related materials than I do.

[Q-Man]

I built some University Classic folded bass horn cabinets. They use a C15W (15" woofer). They have a 107db to 110db/watt sensitivity & are strong down to 40Hz. When I compared them to my klipschorns, I was surprised how much louder they are.

My real goal is to build a bass horn that can go down to 20Hz and be very efficient at that frequency. The horn will be too large to fit in a room. I'm trying to figure out how to build and fold it into the attic space above a new home theater room design. The mouth of the horn will be about a 16' to 18' square and blend into the ceiling. I want to use it as a sub for an all Klipschorn based home theater.

Horn Ed, I finally figured out where to put my subwoofer in that drawing I sent you.

Q.

[djk]

Bill:

Your articles in SB were not worth the time or postage to reply to.

Why not take this to http://64.154.92.195/forums/hug/bbs.html

where it belongs?

Unless, of course, you are worried that Bill Geiger, Dr Bruce Edgar, Tom Danley, and the others will hold your feet to the fire?

[fitzmauricew]

If those guys are so great how come they haven't figured out how to get a folded horn to give the same response as a direct radiator? Bruce Edgar couldn't get an EVM12L to work above 400 Hz in a folded horn- he said it couldn't be done. My DR12 box gets 114dB at 4KHz from the same driver. I'll give credit where it's due, but I 'll also take it when I deserve it. Since SB became AudioXpress I've had six folded horn projects published. Where can I see your work? And what is the name of your book so I can order a copy?

[DillonW]

fitzmauricew- There are a number of reasons why horn loaded speakers are less prevalent than in days past. They have very strong positives, along with undeniable weaknesses. That is, their efficiency is their true strength. Today efficiency is not nearly as important as it was 50 years ago. We have high-powered amps that can drive the daylights out of the most power hungry speakers. The weakness of a horn loaded speaker is its size and weight. Industrial systems use mega-watt amps, so why haul big, heavy horn-loaded speakers when you can just get bigger amps and carry more, smaller boxes? Its just logical. Although less viable for commercial use, many of us believe horn loaded speakers provide the most accurate sound reproduction. So enlighten us as to your designs. Post some pictures or drawings. If you want to be taken seriously, don't get all high-handed in your first posts. If you do know what youre talking about, your posts will be insightful and informative. We welcome anyone who can provide these types of contributions. On that note, you owe Trespasser Guy an apology. He stated up front the topic was out of his league, but wanted to ask an honest question. You had the option of teaching a willing student, but no, you had to take a cheap shot at him. Most of us participate in this forum to increase our knowledge, and fellowship with other Klipsch fans. Many of us are also very interested in bass horn designs. We would welcome any constructive conversations from you on this topic.

[fitzmauricew]

Apology extended to trespasser guy. As to the rest, what you say reflects the prevailing attitude in the industry. When cheap high-powered solid-state amps became available some 30 years ago the industry gave up on the folded horn cabinet in favor of T/S boxes, not because T/S cabinets are the best choice for concert level sound, but because they are more profitable. They are cheap to build, and with only 100dB sensitivity they sell a lot of them. At the same time the rush to apply T/S parameters to everything encouraged well meaning designers to wrongly conclude that folded horns wont work in the midrange. They also came up with formulas for throat size, taper rate, horn length and mouth area that resulted in the overly large folded horns that today are only seen used as subs. Since the experts said that folded horns wouldnt work above 500 Hz at best and had to be very large to work at all no one tried to build a compact folded horn for full range use.

Those formulas, and all the assumptions made because of them, are wrong. Take the tuba, which is a folded horn. Yes, the pipe being driven is some fourteen feet long. But the mouth is only 16 inches across, not the seven feet that some folded horn designers would have made it. The source driving that horn is not an eighteen-inch diameter cone driven by a thousand watts- its a pair of lips with maybe a watt of available power. And does the frequency range of the tuba top out at 250 Hz? Hardly. Luckily, the inventors and refiners of the tuba and other brass instruments didnt have T/S theory and other pre-conceived limitations holding them back- otherwise symphonies would have kazoo sections instead of brass. No offense intended to kazoo players.

When you apply the lessons learned in 500 years of brass instrument design to the relatively fledgling area of loudspeaker design you can come up with folded horns that are not only more efficient than other designs, they are also smaller and lighter in weight, with wider bandwidths. The average electric bass player today uses a 4x10 T/S box that comes in at over 6 cubic feet, weighs 75 pounds, has a low-end cutoff (-10dB) of 100Hz, and with 98dB efficiency requires 200 watts to drive it. I play my bass through a 3.5 cubic foot 30 pound folded horn loaded with a single ten. Low-end (-10dB) cut-off is 60Hz, and with 104dB sensitivity its happy with 50 watts input. The woofer bandwidth extends to 3.2 KHz. The argument that its more logical to use T/S boxes powered by kilowatt amps than folded horns only applies to the folded horns on the market today, none of which are significantly different than those of forty years ago. That includes the latest from EAW, which is an interesting design but still works only as a sub.

My only intent with the initial posting on this forum was to ask a question of Klipsch- are they interested in advanced folded horn technology? I built my first folded horn after I saw Paul Klipschs work, first copying what he had done, then refining it, eventually going on to make my own contributions to the genre. Klipsch was once on the cutting edge of folded horn design, both for the home and for pro usage. They arent anymore. Id like to see my work marketed, and Klipsch seems a logical company to do so- if they want to get back to what made them great, and if they can get past the not-invented-here syndrome.

I cant send photos or diagrams to this site, as all of my work has been published, and it would be a violation of my publishing agreement to offer those items to another source. Those who would like to see what state-of-the-art folded horns look like can log on to audioXpress.com, and see about back issues with my projects. These are all pro-sound designs- dont bother if youre looking for a hi-fi sub. And while I dont plan on making this site a second home I will stop by from time to time if anyone is interested in posing questions.

[DillonW]

Sorry, but I dont think Klipsch is developing new horn technologies, at least nothing on the scale of the heritage series. Honestly, I think tradition is the only reason they still make those. There sure doesnt seem to be any efforts in the marketing department. I guess thats what happens when market share and profit margins become a companys primary objective. Its a bit disappointing, but I guess I cant blame them. In looking at the site you referenced, I did not see any of you work available for viewing, without subscribing. Maybe I missed it, if you have a URL please post it so I can take a look. Have you actually built some of your designs? If so, there is no reason you cannot post pictures of units that you have built and own. Unless you have sold the rights to your designs, there is no reason you cannot post sketches to illustrate them. I for one would be very interested in seeing new folded horn designs.

[basshornguy]

Hey, I built this guys DR12 in the july 2001 issue and its louder than my old 8x10 Ampeg bass cab. I subscribed just so I wouldn't miss any of his new stuff,and it was worth the price. The DR12 worked so well that I built his DR10a this summer and I use it more than the DR12,cause its so small it fits in the trunk of my car-dont need a pickup truck no more. My keyplayer owns the PA and he compared my DR12 to his EAW LA215's- the DR12 is half the size and twice as loud. Soon as he can build a couple of DR12s his EAWs are up for sale.

[DillonW]

basshornguy- Congratulations! You must be pretty proud of your DIY project. Please post some start-to-finish pictures of them if you have any, or just post pictures of how it turned out. Sounds very interesting. What did you construct them out of? What drivers did you use? But, above all, pictures please.

[fitzmauricew]

Here is a photo of the as -yet unpublished DR10 Mk II.

[fitzmauricew]

The DR10 Mk II halfway through construction.

[fitzmauricew]

The DR10 Mk II SPL when loaded with Eminence Delta 10. These boxes are not easy to build and to attempt to do so without having the original magazine articles would be fruitless. I also can't post for free what the publisher is entitled to be paid for- that's invasion of copyright. I do freely give construction advise to those who have obtained my plans via legimate means.

[DillonW]

Thanks for the pictures. I don't think anyone here is interested in trying to duplicate a design based on pictures. The truth is, you simply cannot ignore the old saying... "A picture paints a thousand words." If intriguing enough, plans will be obtained legitimately. I must say it does look interesting, but still pretty big. What is the overall size?

[fitzmauricew]

The DR10MkII measures 28wide, 20 high, 26 deep, weighing 50 lbs with drivers. This is almost precisely the same size as the Peavey Subcompact 18; for comparision Ive attached the DR10 MkII SPL with the Peavey SPL also shown. The Peavey design is typical of commercial folded horn subs. It doesnt have any midrange capability, and isnt all that great in the bass either. My DR horns work full range and dont need subs . True, the Peavey Subcompact 18 is a very small box as far as subs go- their 18 cubic foot DTH118b works a lot better. But my DR12 at 13 cubic feet is on average 6dB more sensitive than the DTH118b below 100Hz, and while the DTH118b has to be crossed over to a woofer at 250Hz, the DR12 woofer runs from 32Hz to 5KHz.

I will probably not publish the DR10MkII in its present form. This prototype proved to be not tunable for differing driver Fs. All the other cabs in the DR series can be tuned over a wide range of driver Fs. I wont supersede the original DR10 until Ive corrected the MkIIs deficiencies, which likely will not be until next summer. That timetable is dependent upon a planned redesign of the DR12, which might happen next spring. Im talking with a major venue right now about a permanent install to replace their EAW KF760/LA400 arrays, and if that comes to pass Im going to redo the DR12 for a line array configuration.

Im not concerned with others trying to build DR cabinets with my photos as their guide. Ive already been paid for the publication of my designs, and wont see another penny no matter how many magazines are sold containing them. Its just that I assigned my rights to photos of those published projects to the publisher. If he wants to post them on websites he can; I cant.

[roger dan]

I am very interested in building a horn with greater than 104db/w.please send me the design that can be used with a 12" driver.So far I have only built the klipsch la scala bass section and the dynamics are awsome.