AKABAK Resistive Cardioid Interface Set-up

[CinamonRolls]

Hi, what is the correct way to set up the AKABAK subdomain interfaces for modeling resistive cardioid polar patterns?

I currently have exterior and interior subdomains separated by an interface. However, I have two Element Meshes within the Interface. Both located at the exit of the resistive port separated by 0.25 mm and both are set to Wall Impedance. One faces to exterior domain and the other to interior domain as can be seen in the attached images. I've never seen images of both sides of the port interface so I don't know how to set it up correctly. Thanks.

Interior vs Exterior meshes both located in one Interface separating the interior from exterior subdomains.

 

[Scgorg]

Hello!
You only have two subdomains, and as such you should only use one interface connecting those subdomains. I generally choose to let the interior subdomain extend to the very end of the slits, and then place the interface there, see the image below:

The important part is that your interface has its normals facing the right way (you determine the correct direction of the interface when configuring the interface (not the mesh)). In this case the interface points in towards the interior domain, and so we can see that the normals of the interface mesh is configured to point in that direction.

Note that you don't have to apply a damping coefficient to the interface like you have done here, as it is by definition acoustically transparent. Adding the damping doesn't change anything.

 

[CinamonRolls]

Thanks for the help. I went looking for a "How To Model Resistive Cardioid in AKABAK" and couldn't find one. Maybe there are tutorials on the subject but I chose poor word choice in my searches.

 

[tmuikku]

I experimented with it a lot few years back, and could not get to match real world speaker measurements. Doesn't mean it is not possible, but you likely won't find out the sims won't match reality exactly. I'd say build a prototype and experiment with it, faster and more real than sims in this case. You'd need real speaker with measurements to validate a sim setup is working as it should.

 

[tmuikku]

i wrote that in a haste what I ment the results just weren't reliable in sense that I could not simulate the damping material so that it would match reality. Its about as good as it gets if you just put all inside walls damping some, and nothign to the apertures, like mabat did in ATH thread in diyaudio. Basically youd adjust either your real world damping material, or damping in the sim, and try to find a match either way.

What I suggest is make a real world example and try to make equivalent simulation that match the measurements. I had simple setup with screw on panels so that I could vary the apertures, and so on, to get insight how it plays out. Measuring various configurations provide lots of data you can try to match the simulations to. If you crackit though, please post If you can match measurements, you can be confident with sims afterwards.