Would a small folded midrange horn work?

For Eminence's Delta 10A - say either a mini-La Scala ~ 15" cube or a "C" horn. If you've something in this ballpark I'd like to see the plan. Simpler is better.

just like to have a fun toy - one of Dr. Edgar's first Speaker Builder Magazine's articles concerned a folded midhorn.


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where would a C horn roughly of dimensions in this sketch poop out with retards to usable top end? - I'd like this toy to be no larger than ~64 liters bulk and a light cabinet to offset the clunky ferrite slug Delta10A

maybe one of the horn-pa guys here can tell what will fit and work in such a box. (it could be more cubical as long as bulk is fixed or not exceeded)


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For the C horn with that kind of angular fold I would expect 250Hz to around the upper usuable limit. A simlar popular design is the HD15 . Perhaps consider something like the Fulcrum acoustics FH/SH series where the horn path is straight but a 180 degree turn is performed in the compresion chamber to reduce depth.

This horn is straight but there are measurments for the Peavy PV1 in the thread which hits 500Hz with a bend: https://www.diyaudio.com/community/threads/mega-midbass-straight-horn-139db.349105/
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(-that's my FH1 dragged out doors in that plot.) Eminence's Delta10A's reponse may aid function ikn the horn. I've not driven for over 25 years and very little before that due to vertigo since ~1971 - go nowhere - just want a toy.

I'd like to keep the total weight with driver to 17kg max


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thanks kipman725 - - with 250Hz top end it would be about a half-octave device :rolleyes:

perhaps as a "W" it might go a bit higher.

one of the late Dr. Bruce Edgar's earliest Speaker Builder articles was a "W" fold midhorn for barber shop quartet duty - - I'm not sure if the article is online.
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Freddi I'm currently designing something very similar to your Delta 10A midhorn as well, with an upper limit of 500-600 Hz. Hornresp agrees with that, but the bends may spoil all of it. Page 868 of Bjorn Kolbrek's Horn book discusses various shapes of bends, reporting - if I understand well - that the best bend is the radiused bend with inner radius equal to half the outer radius; reflectors in square bends, or outside radiused bends with a sharp inner corner are told to be not (that) effective.
So it's all in the bends, I'm afraid, and kipman725 mentioning 250 Hz with the shown picture will sure be bloody right.
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Simpler is better.

Hello Fredi,

I've been playing around with model to get the best output possible from my 10" speaker Snake ESX310, and I reached the attached design that may fit your needs. I has only one bend easy to round.

Total volume: 94L
External dimensions:
Width: 31cm
Height: 58,6cm
Depth: 50cm

I choose dimensions to better fit on top of my Tapped Horn. I also have a 122L version that goes little lower. I'm still thinking witch one I'm going to build in near future. You can easily tune the dimensions to your needs.

Attached FreeCAD model zipped and Hornresp simulation with Eminence's Delta 10A.

it's a mixture of the SmallHorn design with Martin Audio WLX version.

Note: Take into account that the two small chambers will be connect with the big one, i just didn't represented in the 3D to run it fast, but it's very simple to modify while building cutting the 4 square edges and make it octagonal. Bigger chamber will be better just to have more air and maybe increase the time the driver take to reach maximum heat once the chamber is sealed. Bigger or smaller chambers doesn't make much different in the output SPL in this case.



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I don’t think bends really hurt anything, as long as they are reasonably smooth and you don’t have nasty constrictions along the horn path. A few years ago I did a driver shootout in my kick bin design, which is similar to this but longer and need not go as high. It was originally adapted from something designed for the Kappa Pro 12 (on right), but I really wanted a driver with a 4” VC instead of a little kapton one which heats up in milliseconds. Mass corners on most sub or bass drivers were just too low, 50 to 65 grams was about right, 100+ just too much. When loaded with that Kappa Pro, it started rolling off around 400, as expected. While this would have been ok, I was looking at increasing thermal mass. Tried (for $#its anf giggles) that red surround version of the Delta Pro, and it was going strong at 1 KHz, despite the Hornresp-predicted offset driver null at 600 Hz, and mass corner around 800. The PRVs were in between - giving me useable response to about 800. I went with the bigger one, of course. The application only calls for 400 Hz capability, but the horn itself could obviously do more.

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beautiful set of horns wg_ski ! - would love to experience them.

(I've not heard live music for ~20 years)

@LORDSANSUI - that is a horn
I'd love to have - great size and smooth. If there's a drawing with dimensions available, I'd surely would be interested.

out of two midbass horn I had made by
Jesse Brunner, I think the scaled University Classic goes higher
and has an exciting sound. If it had been an inch deeper than could have used a 12"

The "C" path horn is getting rough by 400Hz. I think the little Classic could wobble up to 800.

Is there some magic in the Classic's compound angled throat section ?


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I don’t think Lordsansui’s horn would be all that difficult to reverse engineer from the Sketchup and Hornresp inputs…..

I was looking at loading a quad that had similar response and horn flare with 12MH32’s. In simulation of course, and for a project I may or may not ever get to. Already bought the drivers on the PE 4th of July sale. That looks like a workable fold to me if trying to keep the midrange smoothed. I still have this crazy idea of a multi-KW, 3 way active all tube PA rig, so the wheels are ALWAYS spinning. Those existing ones were made for my big SS rig and 4 of them stacked vertically fed with 2x40 watts will pin you eyes in the back of your head. Sound is surprisingly good with no sub or tops, just running full range. The idea was to have a stack of those run next to a stack of Unity’s, with all 16 of my low-tuned subs. Someday.
If there's a drawing with dimensions available, I'd surely would be interested.
Hello Freddi,

Yes, check the attachment I posted to you (post #11), there is a FreeCAD file there named: SmallHorn3-586x500-94L.FCStd

Once is a CAD files it contain all dimensions you need, in addition it contain the 3D and a spreadsheet with all hornresp input data.

If you never tried FreeCAD model, It might be a good opportunity.

In the website there are videos explaining how it works in case you need additional information.


Is there some magic in the Classic's compound angled throat section ?

Looking to the model you attached it looks like offset horn, so it will introduce dips in the frequency response narrowing the bandwidth. Better to front load or use a side panel and throat adapter to a eliminate the offset load and related reflections.

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@LORDSANSUI - thank you very much. As far as practicalities I'm "73", noty driven for 25 years and have many health issues - but love speaker and horn approaches.

Your horn is exactly the bulk of a Karlson 12 cabinet (1955-1973) so a comparison


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thank you very much. As far as practicalities I'm "73", noty driven for 25 years and have many health issues - but love speaker and horn approaches.

Welcome, I would be happy to reach you age with the same enthusiasms :)

Attached you can find the Hornresp data for the 122L version to compare.

Just replace the driver for the one you interested.


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