Acoustic Horn Design – The Easy Way (Ath4)

While considering suitable materials (leaning towards soft plywood), I came to the conclusion that a throat adapter could be useful for switching drivers.
This adapter would allow exchanging drivers with the same exit size, but with different throat angles.
It's not so easy as changing the throat angle changes the whole profile. I thought about that several times but always gave up.
 

Ro808

Member
2010-03-27 4:25 pm
Interesting comparison between 2 populair 1" drivers (from hifi.slovanet).
 

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Can somebody post the ABEC results of a good horn they have simulated?
I'm trying to design a 3cm throat / 30cm mouth one and looking for inspiration :)

This is what I would recommend: #1402
It has elliptical guiding curve and circular mouth. The result is remarkably smooth, still of reasonably CD and almost without a hint of narrowing.

If you prefered rotational symmetry because of the ease of manufacturing, this would by my bet: bmc0's waveguide (should be possible to come very close to that shape with Ath)

And of course, there is a variety of promising squarish/rectangular shapes, some of them showed here, several pages back.
 
If I were ever to use a large format 2-inch driver as a wide-range source, it would probably be with something like this (27" x 14") -

(There are some numerical defects above 3 kHz, probably still due to mesh coarseness, otherwise it should be pretty smooth.)
 

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BTW, this is what I get for a waveguide probably not far from what bmc0 has shown in the other thread (0 - 90 / 10 in an infinite baffle; normalized at 15°). It is stricly axisymmetric so that makes it harder to get rid of the ripple but I think what he achieved is already pretty good for the size.
 

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Ro808

Member
2010-03-27 4:25 pm
The horns in posts # 2073 and # 2076 are particularly interesting because of their depth.
I wonder what the response in the upper octave looks like, since the throat is no longer visible about 30° off-axis.
Given the depth, I am afraid the waveguides will also sound (more) like a typical horn, ie "cuppy".
It is consistent with Holland & Newell's findings: horns with an axial depth > 30 cm are likely identified as horns in a controlled blind listening test, with the exception of multicellular horns.