AKABAK 3

I just upgraded my ABEC 3 to AKABAK 3. The most difference compared to the former is the GUI. This is a big improvement to the original script based input for some users (me too). :)
 

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Speaker component example

A simple example for using Speaker component.

In order to generate polar plot and SPL at 1m, we need to add some stuffs for direct sound analysis.

The AKABAK file is attached as a zip file.
 

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  • Speaker component.zip
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  • Speaker component outputs.png
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  • Speaker component - 3D.png
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I've used v2.1 - the script based version (when it still runs on Win7 desktop)

I guess your are referring to the legacy AkAbak.

AKABAK 3 is a new version of ABEC 3. It is not a new version of the original AkAbak. I spent considerable time to learn ABEC 3. Newly added GUI of the new version would not flatten the learning curve. However, it is useful and improves productivity once you are familiar with the "language".
 
The following pressure box simulation is compared to LEAP 5 and Basta!.

The driver is a flat disc of diameter 37.5 mm. The sealed enclosure dimension is 0.06 x 0.1 x 0.05 (0.3 L). No filling is used. Free-space (4pi) is assumed.

Mesh size of AKABAK 3 is 0.02 m. The same scale is used in LEAP 5 diffraction resolution length with order of 4 selected.

Although Basta! diffraction is likely less sophisticated, its SPL tracks the trend of the other two.
 

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  • Flat Disc Pressure Box LEAP.png
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  • Flat Disc Pressure Box Basta.png
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  • Flat Disc Pressure Box AKABAK 3.png
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How should I begin, as noob, and make it to modelling my loud speakers? I can probably handle the portion of creating the 3d proportions but what to create and what to do with it in Akabak...need a guide or something. In the screen shots above I see a bosic box with a round diapragm, if I could get the level of being able to model this, that would be awesome.
 
How should I begin, as noob, and make it to modelling my loud speakers? I can probably handle the portion of creating the 3d proportions but what to create and what to do with it in Akabak...need a guide or something. In the screen shots above I see a bosic box with a round diapragm, if I could get the level of being able to model this, that would be awesome.

For speaker system (driver, enclosure and crossover) simulation using AKABAK (or ABEC), I will start with CAD drawing for the enclosure and driver (if necessary). I use the gmesh to mesh the CAD. This is essentially similar to one of the bundled examples:

Direct-sound only analysis: root folder/AKABAK Examples/Direct Sound/45 Tower - LE MeasRadiator (you need to have drivers' measured SPL, impedance, etc)

BEM: ABEC21 Sealed Mesh-Files

When I started with ABEC 3, I followed and modified the bundled examples to learn the software. I is not easy at all compared to LEAP 5. In LEAP 5, you input/design your system intuitively. The software takes care everything in the background.

AKABAK 3/ABEC 3 needs substantial human "interventions" for proper modelling, in particular involving BEM and external mesh files. I am stilling learning. It forces us to know more the physics and modelling. It is good eventually.

Start with the examples. This is my humble advice for beginners. :eek:

I made a youtube video for the pressure box examples. Hope that help.

YouTube
 
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I found a video on youtube....that was very helpful, I've just done more with the program tham ever...when I went to solve it asked for vac...I have downloaded vac and put it contents into the akabak folder, but the program tells me it cannot find/load the cansimportant_balloons....

Is VACS opened when you select "Options->Open VACS" or click the "VACS" icon in the tool bar?
 
Simple sealed box simulation

The aim of this exercise is to familiar the design flow of AKABAK. A simple sealed box with a cone loudspeaker driver is used. In contrast to the previous pressure box (direct-sound analysis) example, we move into the “heart” of the software – BEM. There are more steps needed to accomplish it.

The enclosure and driver dimension are somewhat arbitrary. Outer dimension of the enclosure is 100 x 170 x 110 mm. Uniform wall thickness of 5 mm is assumed. Symmetry along z-axis is used. Hence, BMR parameter dialog is as shown below.

BEM%20parameters.png


We therefore only need to define nodes of one-half size of the box and driver. Note we need to define both nodes for external and internal walls as depicted below.

Enclosure%20nodes.png


Nodes for setting observation fields and points are needed as well. Two subdomains are used. Subdomain with EIType = exterior is used for the free space (enclosure external). Subdomain with EIType = interior is used for enclosure internal.

Neumann boundary type is set for enclosure external elements. On the other hand, wall impedance is selected for enclosure internal elements.

Shell component is used to model the driver front surface which is belong to the enclosure-external subdomain. The rear driver surface associated with the enclosure-internal subdomain is inherited from the front surface.

BEM%20components.png


Lumped-element schematic is illustrated in the next figure. The parameters are somewhat “typical” for a 4” driver.

BEM and field mesh size are rather large to minimize computational time. Once the model has been solved with error, we can increase mesh density.

LE%20components.png


Enclosure internal ad external nodes.
Enclosure%20nodes%20-%20details.png


Node for observations.
Nodes%20for%20observation.png


BEM exterior subdomain.
BEM%20component%20-%20exterior.png


BEM interior subdomain.
BEM%20component%20-%20interior.png


Observation setting.
Observation%20setup.png


Result.
Result.png


The file for download http://akabak.pansonaudio.com/Sealed LE+BEM Box 1.akp

Let me know if you find any error. Have fun!
 
Simple sealed box simulation

The aim of this exercise is to familiar the design flow of AKABAK. A simple sealed box with a cone loudspeaker driver is used. In contrast to the previous pressure box (direct-sound analysis) example, we move into the “heart” of the software – BEM. There are more steps needed to accomplish it.

The enclosure and driver dimension are somewhat arbitrary. Outer dimension of the enclosure is 100 x 170 x 110 mm. Uniform wall thickness of 5 mm is assumed. Symmetry along z-axis is used. Hence, BMR parameter dialog is as shown below.

BEM%20parameters.png


We therefore only need to define nodes of one-half size of the box and driver. Note we need to define both nodes for external and internal walls as depicted below.

Enclosure%20nodes.png


Nodes for setting observation fields and points are needed as well. Two subdomains are used. Subdomain with EIType = exterior is used for the free space (enclosure external). Subdomain with EIType = interior is used for enclosure internal.

Neumann boundary type is set for enclosure external elements. On the other hand, wall impedance is selected for enclosure internal elements.

Shell component is used to model the driver front surface which is belong to the enclosure-external subdomain. The rear driver surface associated with the enclosure-internal subdomain is inherited from the front surface.

BEM%20components.png


Lumped-element schematic is illustrated in the next figure. The parameters are somewhat “typical” for a 4” driver.

BEM and field mesh size are rather large to minimize computational time. Once the model has been solved with error, we can increase mesh density.

LE%20components.png


Enclosure internal ad external nodes.
Enclosure%20nodes%20-%20details.png


Node for observations.
Nodes%20for%20observation.png


BEM exterior subdomain.
BEM%20component%20-%20exterior.png


BEM interior subdomain.
BEM%20component%20-%20interior.png


Observation setting.
Observation%20setup.png


Result.
Result.png


The file for download http://akabak.pansonaudio.com/Sealed LE+BEM Box 1.akp

Let me know if you find any error. Have fun!
 
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Joined 2012
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Looks nice but I have spent the last 7 years using original script based Akabak and I have hundreds of reusable code snippets. I now run it on a virtual machine that runs WinXP in order to use it. Copying and pasting the resulting plots between the VM and main Win64 OS is not a problem. I do not think I will relearn Akabak language anytime soon. The 3D modeling capability is key for simulating the higher frequencies for mids and tweeter and interaction with a horn or waveguide though.
 
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More questions.
I managed to make OB enclouser mesh file with GMSH and imported it to Akabak.
Box is visible but not find way to get speakers visible on BEM view.
Must I also define for OB exterior and interior subdomains?
How Diaphragm can be attached to enclouser created from mesh file?
 
Must I also define for OB exterior and interior subdomains?
How Diaphragm can be attached to enclouser created from mesh file?

You may not need to exterior and interior subdomains for the overall OB. I made something similar before for IEC baffle. Please take a look of this project. Note that it is not completed and error free.

You can use shell or diaphragm element of AKABAK to model the driver. The enclosure should have a hole for the element to "mount".
 

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  • IEC Baffle-Cone-3D with Shell- LE+BEM.png
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When I open on AKABAK the Speaker Cabinet SP38 Mesh-Files - OB file, I not see actual mesh file defined box on BEM view.
Must it be non-visible or my AKABAK had some settings wrong?
Also I not find way how to define diaphragm with hosting baffle and how to align it to mesh defined box?
 

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