Acoustic Horn Design – The Easy Way (Ath4)

[Nissep]

Nope.. I was wrong, might be the doable driver adapter that first mentions it.

 

[miero]

Measurement of the SB Audience 65CD-T compression driver with a custom rear cover No.1993 seems to be here:
- https://josephcrowe.com/blogs/news/smooth-transition-throat-adapter-no-2322-for-yuichi-a290

There does not seem to be anything wrong with the upper treble detail if paired with an appropriate driver such as the 65CD-T with rear chamber No.2376.
...
When listening to the 65CD-T I decided to increase the LR4 300Hz HPF to 500Hz. This completely alleviated the resonate sound character I mentioned earlier.

 

[mabat]

I'm working on a second generaton of the kits and I'm pretty excited about it. I should have come up with this a long time ago but I considered it difficult. In fact, it's not. The basis is an axisymetric 1.4"-throat waveguide, ⌀520mm overall, cut at a diameter a little larger than 2". This way, an extension can be made for basically any target throat diameter requested. Of course it's not possible to continue the extension with the same R-OSSE profile, but that can be dealt with easily, as it turns out.

 

[mabat]

- If made as a "regular" 1.4" throat horn (it means a 41mm extension piece to the basic part above for an exit angle 8°).

 

[TNT]

Have to ask (again?)... the upwards slight tilt (of the mostly linear DI trace) - is this deliberate or is it that it is not possible to get a more non-tilted, still linear, trace?

//

 

[mabat]

It's one of the design choices. See page 16: http://www.at-horns.eu/release/R-OSSE Waveguide rev7.pdf#page=16

I just tend to target roughly a 3dB rise of DI between 1k - 10k for the direct sound.

 

[TNT]

Thanks - I forgot about that valuable set of information - sorry. Have you compared a 3dB rise and a "flat" one with the same CD and LF unit? Just curious to understand what it means for the listening experience...

//

 

[mabat]

No, no such direct comparison yet. The added rise of the DI allows for a flat direct sound and somewhat tilted-down sound power. If sound power is flat, it just sounds too bright in most cases. The solution then is to add some downward slope, but with a flat DI this means that also the direct sound gets tilted down as well. So this is the rationale. It has a lot to do with the circle of confusion, I guess. This has been discussed a lot, without any clear conclusion, as far as I remember. It only must not beam to much.

 

[Olombo]

DCX464 waiting....print in progress. My printer can do 300x300x300...that is maxed out followed by 4 ring segments. We need larger printers

 

[maiky76]

To complement this post
https://www.diyaudio.com/community/...he-easy-way-ath4.338806/page-729#post-7646612

Here is the Peerless DFM2544 on the ST260

The Peerless driver look very smooth, anyone tried a Celestion CDX1-1740?
These also look smooth.

 

[mabat]

The first "Gen2" kit is almost finished - 1.4" throat, axisymmetric, ⌀520 x 275 mm, no extension.
Already in the print.

1" version will be the next, the same body, different extension piece. Then more and different extension pieces will be made, as I will progress with the development. The directivity will always stay basically the same - that's given by the throat geometry as shown in the above pictures.

 

[mabat]

1" extended throat - as simple as this.

 

[kodomo]

This can be a great solution for 800hz-20khz with a TAD 2001 or a Beyma cp380m with a much less cost

 

[Kevmoso]

Would there still be a benefit to running the 1 inch throat size down smaller to fit up against phase plugs such as your EXAR 340-20?

 

[mabat]

The directivity is already given by the base shape, but it could help to further smooth the response.

 

[mabat]

This is for a 1" throat without a long extension -

The directivity control is so-so, I think it could be still acceptable, maybe not.
This has been actually not optimized yet, I may still try to run an iteration or two, but I can hardly improve the smoothness.

 

[mabat]

...optimized

 

[TNT]

Could you please consider to offer this size but with a more flat DI - perhaps not +/-0 but say 1dB tilt? Personally I would like to have more contribution from diffuse HF coming "later" to the listening spot - it seems to make up for a much more natural experience when playing orchestra music recorded in a concert hall.

//

 

[mabat]

I think there are better options for a wide and controlled directivity. Large and deep hard domes (Bliesma T34A) in shallow waveguides are amazingly good for this. And I guess that by far the best will be some delayed "ambient" signals, even if from two more added sources. Otherwise you'll never achieve the delays/levels necessary for a convincing illusion of a large venue. My choice would be two strong direct field sources (waveguides like the above) + some delayed channels, whatever they would be.

Maybe with some additional narrow waveguides, aimed away from the listener (for the longest possible time gap via reflections), one could do at least something even without the increased processing complexity or DSP. (And what I would like to know, is what frequency range is neeed to cover for this.)

 

[danibosn]

Hi everybody

I do not want to spoil the thread to much but as I want to jump in 3D printing train as completely newbie and here are several experienced people, I need an advise about printers.

Will below be good and big enough for waveguides printing?

https://store.creality.com/eu/products/ender-5-s1-3d-printer

Will be smart to upgrade to K1?

Thank you