Acoustic Horn Design – The Easy Way (Ath4)

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T

Twellmann

Member
Joined 2008
Hi Marcel

Can you give my a hint with exporting the surface to Fusion360?
The .STL file looks fine. I can also import the ESP shape into fusion without any problems.
1647466330961.png
1647466472245.png

I have copied the code from the .pdf file, but I am not certain about the parameters:

Code: 
Rollback = 1
Rollback.StartAt = 0.4
Rollback.Angle = 180 ; [deg]
Rollback.Exp = 1.5
Mesh.AngularSegments = 32
Mesh.LengthSegments = 60
Mesh.SubdomainSlices =
Mesh.WallThickness = 4 ; [mm]
Mesh.ZMapPoints = 0.5,0.4,0.5,0.98
ABEC.SimType = 2
ABEC.SimProfile = 0
ABEC.f1 = 200 ; [Hz]
ABEC.f2 = 20000 ; [Hz]
ABEC.NumFrequencies = 100
ABEC.MeshFrequency = 42000 ; [Hz]
ABEC.Polars:SPL = {
 MapAngleRange = 0,180,37
}


GridExport: = {
 ProfileRange = 0,32
 SliceRange = 0,32
 ExportProfiles = 1; 0|1
 ExportSlices = 1; 0|1
 Scale = 1.0
 Delimiter = ";"
 FileExtension = "csv"
 SeparateFiles = 1 ;0|1
}

In this configuration I get 32 separate .csv files with 33x3 values and an empty one, if I set SeparateFiles = 1.
When I set it SeparateFiles = 0 then I get one big file with +900 lines, where it seems like the last section is incomplete.
If I use the ath4_CurvesImport script in Fusion360 on the large file, then I get the profiles, or at least most of them:
1647466298409.png


But, when I try to use ath4_SurfaceImport on the same file it doesn't work.
So what should my ProfileRange and SliceRange be?
Should ProfileRange be smaller than Mesh.AngularSegments?

Looks like it works with importing the surface, but I'm not sure if I have exported the whole thing. I have set SliceRange = MeshLengthSegments - 1, I guess there can't be overlap in the mesh
1647467228506.png


I'll keep on trying :)

-Daniel

EDIT:
Great succes
1647468817518.png
 
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T

Twellmann

Member
Joined 2008

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mabat

mabat

Member
Joined 2004
at-horns.eu
Paid Member
Yeah, that was the easy part :)
Somewhat more difficult is to print it and (at least for me!) a lot more demanding to actually test it - I have already so many things waiting in the cupboard to be measured that I don't think I will be ever able to finish it. Some day I just might throw it all away...

So I wish you a good luck. I think this could well be the future - at least for DIY.
 
camplo

camplo

Member
Joined 2019
Jokerbre said:
REW files you can find in links below, so you can play :)
https://drive.google.com/file/d/1GImZETlKzAOpmDzhJoGrPyE19Y5Rj-Hp/view?usp=sharinghttps://drive.google.com/file/d/1yMDZ3UoSbuXVtSomP8dLRjhcIZwLxbmP/view?usp=sharing
Impedance data:
https://drive.google.com/file/d/1ewcZIsDVt9XGKwI9sZeiBTib1e4BF4te/view?usp=sharinghttps://drive.google.com/file/d/1aUDe6r8SMbmfdKygPlVMBDQvP79f_3C0/view?usp=sharing

View attachment 1027270
View attachment 1027271
View attachment 1027272
Click to expand...
Jokerbre, are these file still available?
 
sheeple

sheeple

Member
Joined 2020
fluid said:
Morph.CornerRadius = 1.5 Corner radius for a rectangular outline [mm]
Click to expand...
Great.

What I am after is the most simplistic waveguide, consisting of two profiles only. I cannot achieve this atm. The walls have a curvature which is variable across their depth. This inhibits to create a waveguide from two splines, simulate it and then build it with.

How can I enforce two simple splines?

Code: 
Throat.Diameter = 25.4
Throat.Angle = 10.08
Throat.Profile = 1
Length = 100

Coverage.Angle = 50
Term.s = 0.7
Term.n = 3.7
Term.q = 0.995

Morph.TargetShape = 1
Morph.FixedPart = 0
Morph.Rate = 1.01
Morph.CornerRadius = 1

Source.Shape = 1
Source.Curv = 0
Source.Radius = -1
Source.Velocity = 1

;___________________________


Mesh.AngularSegments = 60
Mesh.DepthSegments = 20
Mesh.CornerSegments = 5

Mesh.ThroatResolution = 4.0
Mesh.InterfaceResolution = 9.0
Mesh.InterfaceOffset = 5.0

curvature2.jpg curvature.jpg
 
F

fluid

Member
Joined 2009
sheeple said:
How can I enforce two simple splines?
Click to expand...
I don't know exactly what you want but there has to be interpolation between the two splines somewhere to have them meet.

This is a quick sketch of two spline profiles lofted between a circle to a rectangle. If you want the shape to be more specific then you need more guide rails to constrain the loft.
 

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TNT

TNT

Member
Joined 2003
Paid Member
I see now that I probably want to use the ST260-30 with BMS 5530ND... the download has a .step but not a .stl file. Is there any difference when sending this to a printer? JLCPCB accepts both. Viewing the 3D models using JLCPCBs, the step looks coarser...

//
 

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mabat

mabat

Member
Joined 2004
at-horns.eu
Paid Member
The STEP file is in fact independent of resolution - it's an ideal description of the object, and contrary to the STL file it's intended for a further work in a CAD (which then can result in a STL file of some fixed output resolution). To print or visualize a STEP file, it must first be interpreted in finite element terms (as is the STL file a set of triangles). That's what you are looking at and it's a question how they (JLCPCB) do that and whether the visualization matches the actual printed model. I would assume the printed model would be much smoother in the end but you should check (or make your own STL file from the STEP file - e.g. the mounting holes are still missing).
 
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