Acoustic Horn Design – The Easy Way (Ath4)


Please someone show me how to set/know :
ProfileRange : How to know "from" and "to" ?
And SliceRange : Same question

For grid coordinat export

GridExport:<tag> = {
ProfileRange = <from>,<to>
SliceRange = <from>,<to>
ExportProfiles = 0|1
ExportSlices = 0|1
Scale = 1.0
Delimiter = ";"
FileExtension = "csv"
SeparateFiles = 0|1

1" version for those brave enough to try it (STLs) -

View attachment 1049970 View attachment 1049971 View attachment 1049972

- From the right angle it looks like an ear. A coincidence? I don't think so :D (a joke).
Here are horizontal polars utilizing the horn above with the Peerless DFM02535R00-02 (including normalized at 10 deg)

The print wasn't perfect, and I've attached the pieces with just duct tape. I might have also faulted on the placement of the horn+driver combo at the correct rotational axis - so please take these measurements with a grain of salt. Think of these as worst-case scenario :).


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  • Peerless Polars - ST260 - KVAR - Normalized 10 deg Polar.png
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Profiles can be useful as "rails" when using the loft feature in Fusion. I'd suggest at least to import them and check how well does the created surface match these curves. The slices alone may be not enough (depending on how many there are).

- Note that Fusion calls "profiles" what Ath calls "slices", and "rails" what Ath calls "profiles".

Scale = 0.1 is because Fusion API expects centimeters by default.
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These are the two data sets (measured and simulated) merged into one image:

View attachment 1051316
That's pretty impressive correlation - especially considering this was just a tapped-up horn. The dip at 1.8Khz - 1.9Khz is a little more pronounced in my measurement - but again - it could come from less-than-ideal attachment of the two parts (and/or not placing the horn on the exact point of rotation).
I have try F360, but got this error, any idea ?
I have seen this error several times but never figured out the cause. I would do it manually - import only the splines (there are scripts for that as well) and do the rest via the Fusion tools (surface/loft) step by step. That way you have the full control - can select a subset of the curves, add rails, etc.
BTW, I think you have a way too many curves there - that can only cause problems.

I also saw a recommendation to disable the command history in Fusion.
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This is off topic but I'll answer with experience from the older Jab3 without plus. Yeah pretty easy after the process is familiar, but not walk in the park. DSP is programmed with Sigma studio, very flexible, not the easiest one, not too bad as there are plenty of tips on the web. But, the programmer (bought separately) cannot be always connected to the board or otherwise the system doesn't boot up (with sound). Programming needs particular order of hooking and unhooking stuff or custom switches soldered in to manage the connections and make permanent changes to the ADAU1701 chip. Not practical at all, but doable. These boards are not made to be managed daily, more like a set and forget then dump into dumpster after its not working anymore type of product. Can't expect much with equivalent cost of few packs of cigarettes can we. That said, I've used one for three years now. Bluetooth died the first day but otherwise it has been working fine, althought quite noisy with poor PCB design and has too much gain setup, its been good board to prototype speakers with. Cheapest I could find years ago, perhaps still is. You get what you pay for like usual :)
I thought they made interface to simplify ADAU+Sigma Studio.
I also saw a recommendation to disable the command history in Fusion.
This does work sometimes as Fusion will loft things in Direct Modelling that it refuses to do otherwise. You enter it by selecting Do not capture design history.
Fusion is very picky about rails they must intersect each profile/slice precisely. Unless you need them to keep the shape accurate the loft may work better without them.
Did any tutorial as been made for Fusion from point cloud ?
Point clouds are too hard to work with. Try my Solidworks Excel macro as that provides the same functionality as mabat's script.
Instructions in the post below the link above.
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Here are horizontal polar measurements of the ST260 vs ST260-KVAR (same driver, the Peerless DFM-2535, and at the same distance).

Normalized to 10 degrees. I should have included labels, but the ST260 is the smoother one. So impressed with the results.


  • Peerless Polars - ST260-KVAR - Normalized 10 deg Large.png
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