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-   -   Acoustic Horn Design The Easy Way (Ath4) (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4.html)

Patrick Bateman 12th February 2020 06:47 PM

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Quote:

Originally Posted by mabat (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4-post6081803.html#post6081803)
Meshmixer. With a few clicks, hard to beat.

Much improved! Thank you.

mabat 12th February 2020 06:52 PM

Cool!

mabat 12th February 2020 08:39 PM

5 Attachment(s)
So this is the updated comparison - the second take on the "ATH" (on the right). This one looks like a "nude" version of the M2 clone.

OK, the knuckles add this bump in efficiency (?) around 1,7 kHz. Is that all?

fluid 12th February 2020 09:55 PM

Quote:

Originally Posted by mabat (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4-post6081961.html#post6081961)

OK, the knuckles add this bump in efficiency (?) around 1,7 kHz. Is that all?

Seems the over 10K response is smoother without the big dip in the M2 clone, could you extend the sim to go to 20K to see it better? This might well be one of those things that turns out to be different in reality unless you model the exact exit of the driver to horn interface, but interesting as augerpro was putting a lot of effort into minimizing that issue with his shallow waveguides and sim to reality was quite close.

cowanaudio 12th February 2020 11:04 PM

With a 33mm throat the compression driver determines the polar pattern above 10KHz, not the waveguide. I would argue the plots are going too high already.

fluid 12th February 2020 11:10 PM

So why does the simulation change between waveguides when it's being driven by an ideal device?

Patrick Bateman 12th February 2020 11:18 PM

1 Attachment(s)
Quote:

Originally Posted by cowanaudio (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4-post6082126.html#post6082126)
With a 33mm throat the compression driver determines the polar pattern above 10KHz, not the waveguide. I would argue the plots are going too high already.

Yep.

Ideally we should be doing the ABEC sims all the way down to the diaphragm. (including the phase plug in the sim.)

https://proaudiosales.hibino.co.jp/i.../file/3573.jpg

In the JBL 2409H the phase plug is barely there, just a few centimeters deep.

And in the 2410H, it appears to be sticking out of the waveguide itself! Seems to imply that the ring radiator diaphragm may be less than a centimeter from the waveguide.

Basically the phase plug is disappearing.

gedlee 13th February 2020 01:09 AM

Quote:

Originally Posted by cowanaudio (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4-post6082126.html#post6082126)
With a 33mm throat the compression driver determines the polar pattern above 10KHz, not the waveguide.

This is not correct. A waveguide done properly can go well above what is considered the region where it is assumed that the driver dominates.

Quote:

Originally Posted by fluid (https://www.diyaudio.com/forums/multi-way/338806-acoustic-horn-design-easy-ath4-post6082135.html#post6082135)
So why does the simulation change between waveguides when it's being driven by an ideal device?

Because of what I said above, it's incorrect. Some drivers with poorly coherent exit wavefronts may have more trouble than others, but there is no theoretical reason why the above should be true, nor was it true in system that I made.

cowanaudio 13th February 2020 02:01 AM

Try measuring a bare compression driver, they show significant pattern control above 10KHz. How can a waveguide without a diffraction slot make this wider? I'm assuming your "waveguide done properly" does not have a diffraction slot.

cowanaudio 13th February 2020 02:04 AM

Hey Marcel, congratulations on 1000 posts in this thread. It shows the value of the software you have put together here. :cheers: and thank you!


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