Acoustic Horn Design – The Easy Way (Ath4)

[Speedysteve7]

Yes, I'm pretty sure they are. I already measured the driver(s) with a completely different device and it was very similar:
https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-6736091
https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-6736434

It should be no problem to EQ any of this. It's the smoothest driver I have at hand. I expect it to cover the range 600 Hz - 20 kHz with ease.

- I even measured the driver in my wavefront shape experiment. Above 10 kHz it resembles the same FR shape:
https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-7307030

Looking really nice.
I love hex and 12 sided shapes too.

Pretty typical plot I think.
+/-5dB is okay by me.
Judging by the drop off after about 5-6K I'd be crossing in another higher freq driver, or am I missing something?
I use Raal Lazy ribbons above 11KHz and to infinity 🙂, but they would go down to 3.5KHz no problem.
I've also found the best sounds are achieved with no EQ at all, on these frequencies, with my drivers.

 

[mabat]

My view: This horn has a very smooth and gradually controlled directivity through the whole audio band, it would be detrimental to cut it and try to cross to another HF driver, the more so as the driver is capable of nicely covering it all as well... The EQ per se is nothing to be avoided, nothing to be afraid of - it's done all the time, every crossover is an EQ in a sense.

BTW, I think that in this case a good deal of the required EQ can be done passively, by some basic RC network. And then do the rest with an active/DSP setup. Certainly that's what I would do.

 

[Speedysteve7]

Be interesting to hear what you find it sounds like.
It's just over 5 octaves.

 

[mabat]

Yes, kudos to Faital engineers.

 

[mabat]

Faital HF1440 (copied) and 18sound ND3T in ATHEX 460-36 (levels not to scale):
(~ 0/10/20/30 deg @ 1m)

- I don't have more 1.4" drivers in the house

 

[kipman725]

the top octave performance of the Faital HF1440 is particularly good, a product of it being a ring radiator?

 

[gedlee]

Ring radiators do tend to better HF performance due to the lower mass of the diaphragm.

 

[mabat]

The exit wavefront is certainly better behaved. I would suspect it's also the smaller internal cavities and their shapes with the ring radiator. Seems there's simply less room for various resonances to occur. But I haven't measured any other large-format RR CDs.

The HF1440 has an 86 mm voice coil - not actually a small one.

 

[TNT]

It would be interesting to see impedance traces of both.

//

 

[mabat]

I was curious - this is the 2" Radian 760NEOPB with two different throat adapters (32.5 --> 36 mm).
I think that with a proper all-smooth ring plug this will be also very good. Obviously, the shape of the throat has quite an effect on the overall FR.

 

[mabat]

A throat detail with the ND3T:

- What irritates me are the small ripples around the axis just below 4 kHz, I don't see that in the model.

(But maybe it's not the horn.)

 

[Fabio Ferro]

Hallo Folks,

what a great thread here!
Thanks to everyone sharing that much ideas and knowledge.
Does anybody have a printable (30x30x35cm Printer) Horn for BMS 4554, 90-100° H, 1,5-2 kHz XOver?
Thanks a lot!

Fabio

 

[mabat]

Hi Fabio,

ATHEX 260-25 is not what you're looking for?
(I guess I could make it a little wider, but I would consider it 90° as it is.)

Or there's the ST260(B).

 

[Fabio Ferro]

Dear Mabat, thanks for your reply!
the Athex looks intresting, but do you think i could use something like your Tritonia, just smaller?
It´s for PA Tops(sorry, didn´t mention that before). Is there a Tritonia-design that´s max 300mm broad and can be used for 1.4" BMS4554?

 

[sheeple]

Tritonia was designed for 1.4" IIRC.

Just change the "length" parameter (decrease it) until the width of the device is reported to fit your 30 cm target in ath command line output.

 

[Fabio Ferro]

Thanks sheeple,
i can´t use ath, as i don´t use windows. Is there a .stl available somewhere?

 

[mabat]

You can try this one but it's without any guarantee on its performance.

ASC file: https://at-horns.eu/ext/Tritonia-36-290x250x90.zip
(How to work with ASC files for Fusion 360 is described on the ATHEX page).

- Which reminds me I have a pair of BMS 4554 somewhere...

 

[Fabio Ferro]

Dear Mabat, thanks for that, looks great!
I managed to open it in Fusion, but i´m still struggling to get an object from that...

 

[mabat]

Thanks for reminding me the BMS 4554, it's not bad

ATHEX 460-36 / BMS 4554

I think that with a correct throat angle it could be even better (the driver is 26.7°, this horn is 6°).

 

[Fabio Ferro]

You are welcome
To my ears, the 4554 sounded good and musical in many applications.
And it´s quite powerful and affordable in a way.