ATH4 waveguide inspired multi way

Horizontal, 40 off axis. I'll see if I can tilt the reponse anti clockwise 1.5deg without introducing too many ripples.

1647995023706.png
 
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I would suggest to wait for the enclosure simulation - quite a lot will change. It doesn't have to be that resource demanding on the HW, as it can be split into several frequency bands with different mesh densities, etc. And it's the low and midrange frequencies that will change the most.
 
Last edited:
; -------------------------------------------------------
; Enclosure Setting
; -------------------------------------------------------

Mesh.Enclosure = {
Spacing = 31,31,31,346
Depth = 250
EdgeRadius = 28
EdgeType = 1
FrontResolution = 8,8,16,16
BackResolution = 20,20,20,20
}

; -------------------------------------------------------
; Mesh Setting
; -------------------------------------------------------

Mesh.LengthSegments = 20
Mesh.AngularSegments = 120
Mesh.ThroatResolution = 2.0
Mesh.MouthResolution = 10.0
Mesh.CornerSegments = 8
Mesh.Quadrants = 14 ; 1/2 symmetry
Mesh.SubdomainSlices =
Mesh.ZMapPoints = 0.5,0.1,0.76,0.733

; -------------------------------------------------------
; ABEC Project Setting
; -------------------------------------------------------

ABEC.SimType = 2
ABEC.Abscissa = 1 ; 1=log | 2=linear
ABEC.f1 = 200 ; [Hz]
ABEC.f2 = 20000 ; [Hz]
ABEC.MeshFrequency = 1000
ABEC.NumFrequencies = 100

ABEC.Polars:SPL_H_norm = {
MapAngleRange = 0,90,19
NormAngle = 10
Distance = 5
}

ABEC.Polars:SPL_V_norm = {
MapAngleRange = 0,90,19
NormAngle = 10
Distance = 5
Inclination = 90
}

; -------------------------------------------------------
; Output
; -------------------------------------------------------

Report = {
Title = "Limacon Project2-boxed"
Width = 1200
Height = 800
NormAngle = 10
}

Settings above are used for the following outputs. Thanks @fluid for the Mesh.ZMapPoints setting.
 
Comments welcomed. I will try to complete one this weekend and measure. :)

Currently investigating symmetry settings in ATH4 and trying to understand how MapAngleRange works for vertical polar generation and the assymetry (waveguide at the top of the baffle).



Horizontal Data

1648776552074.png


1648777108776.png




Vertical Data

1648776834021.png


1648777336168.png
 
Last edited:
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Joined 2004
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Currently investigating symmetry settings in ATH4 and trying to understand how MapAngleRange works for vertical polar generation and the assymetry (waveguide at the top of the baffle).
This translates 1:1 to the ABEC parameter "PolarRange" in its observation script. Related ABEC parameter is the BasePlane=.
You can change this at will in the "observation.txt" file that Ath generates.

polar_range.PNG
 
Comments welcomed. I will try to complete one this weekend and measure. :)

Currently investigating symmetry settings in ATH4 and trying to understand how MapAngleRange works for vertical polar generation and the assymetry (waveguide at the top of the baffle).
I attached an observation script to look full 360 degrees vertical and 180 degrees horizontal, example code attached, looking to 90 degrees only shows you the edge not beyond, observation scripts can be changed and the new spectra solved without having to resolve the whole model

Code:
BE_Spectrum
  PlotType=Polar; GraphHeader="V Polar Down"
  PolarRange=0,180,37
  Farfield=true; BasePlane=zy
  Distance=2m
  //Offset=200mm
  //NormalizingAngle=10
  502  Inclination=0  ID=5002

BE_Spectrum
  PlotType=Polar; GraphHeader="V Polar Up"
  PolarRange=0,180,37
  Farfield=true; BasePlane=zy
  Distance=2m
  //Offset=200mm
  //NormalizingAngle=10
  503  Inclination=180  ID=5003
 

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  • observation.txt
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Just a remark - you seem to combine Farfield=true and Distance=2m - these two should be exclusive, use either Farfield or a specific distance.

(If you don't specify a Distance in the Ath script, far-field data will be calculated, i.e polars "very far" from the source with level adjusted to 1m with phase corrected for the travel distance I think. I've got used to use this, i.e. omit the Distance item.)
 
True, I often keep things in and comment them out but in this case it would be farfield as the distance is ignored

"Farfield=
Farfield=true or simply Farfield performs the sound pressure calculation at a large distance. Parameter Distance= is ignored.

If Farfield=true then the amplitude gets internally normalized to a distance=1m and the phase at distance=0 (ie normalized to the point of rotation of the observation arc)."
 
I attached an observation script to look full 360 degrees vertical and 180 degrees horizontal, example code attached, looking to 90 degrees only shows you the edge not beyond, observation scripts can be changed and the new spectra solved without having to resolve the whole model

Code:
BE_Spectrum
  PlotType=Polar; GraphHeader="V Polar Down"
  PolarRange=0,180,37
  Farfield=true; BasePlane=zy
  Distance=2m
  //Offset=200mm
  //NormalizingAngle=10
  502  Inclination=0  ID=5002

BE_Spectrum
  PlotType=Polar; GraphHeader="V Polar Up"
  PolarRange=0,180,37
  Farfield=true; BasePlane=zy
  Distance=2m
  //Offset=200mm
  //NormalizingAngle=10
  503  Inclination=180  ID=5003
Hello fluid,
you set Inclination to 0 and 180 degree for verticals. Is there a secret, or am I right that this will produce horizontal read outs? Zero to my understanding is 3 o'clock horizontal plane, 180 degree is opposite side, still horizontal.