Function of source directivity

[郑竞Jing]

Hi,

I am trying to do my thesis about the auralization of different source directivities with I-Simpa, so I wonder if the function of source directivity is ready and verified at the moment. Thank you!

Best regards!

Jing

[JP]

Thank you Jing

The code was verified and tested during its initial development. However, we do not have any unit tests in the code to validate that it is 100% validated. I can only encourage you to perform some tests to make sure that the results are what you expect. Besides, this is part of a thesis work!

We would be very interested in the result of your work and in the way you do auralisation with I-Simpa. I have also been contacted by a fellow researcher who is doing similar work. It might be interesting to get in touch with you.

What university are you at?

Best regard

J. Picaut

[郑竞Jing]

Hi JP, 

I am from applied acoustics of Chalmers University of Technology. I would be glad to share my result with you!

Thank you!

Jing

[郑竞Jing]

Hi JP,

I was trying different directivity balloon with I-Simpa. There are two things catching me and I would like to share and discuss with you.

1. The decay on surface receiver

In order to catch the sound particles emitted from the source, I build a simple scene (a 5m x 5m x 5m shoe box room) with 3 plane receivers (3 plane receivers at 3 orthogonal walls); in my simulation setting,  I tickle [active calculation of direct field only] and generate [Soundmap: SPL]. I expect my plane receiver to catch the directivity pattern with scaling of the geometry. Thus if I have an omni-source in the middle, the middle point on my plane receiver would be max level, the inscribed circle of my plane receiver would be ​(max-3) dB isoline, the escribed circle (only the four corners of the plane) would be (max-4.8) dB. From the result I have, the decaying is faster than I expected. 

--> here I don't know if I have done some mistakes with my scaling, or if there is better way to catch the directivity from source

2. A high level spot for a low pass directivity

I created a low pass directivity balloon with frequency below 1 kHz 0, above 1 kHz -40 dB for all angles; for stop band, a high SPL spot is observed on axis (corresponding to theta = 0 and 180 in I-Simpa directivity setting). 

* I also checked simple high pass and on-axis attenuation balloons, so far I only observe this high level spot in association with LP setting.

 I attach some screenshots of my scene configuration, simulation configuration and relevant results with the message.

Thank you!

Best regards!

Jing

在2021年4月16日星期五 UTC+2 下午7:16:07<JP> 写道：

[nico....@gmail.com]

Hi,

Nice work, thank you for sharing.

Surface receivers give somewhat strange results because of their nature. It is preferable to rely on point receivers for validation.

best regards,

Nicolas

[UMRAE Official]

Dear Jing

Thank you for sharing your work.

I'will take a look and I come back to you.

Best

JP