Grasshopper

algorithmic modeling for Rhino

# Environment factor

Hi everybody.
I made a research classroom model on the change of T30 and SPL by the effects of ENVIRONMENT FACTOR in Pachyderm-rhino. But after the changes I did not notice a clear difference from T30 and SPL. According to previous research by L. Gomez-Agustina et.al. there is a change.
Can anyone who has done research on this help me?

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### Replies to This Discussion

Hi Drum,

I'm not sure I understand, but are you asking about the effects of changing Air Temperature and Humidity?

I ran Source 0 at 1 C and 80 C and got different results (SPL attached). These are less than 1dB; were you expecting more?

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Thank you Nathan for kind help.

You got me right about this research. But in the study of temperature you can see no significant change in case of quite large difference in temperature.
Also I examined the same case (with Air Temperature and RH and SAP) but it has much more obvious differences

Drum,

Yes, this makes sense. For a first order reflection, the distance traveled is about 4.25 m. the speed of sound at 1C is ~ 332 m/s and 80C it is ~377 m/s. Keep in mind that dB is a logarithmic scale and reverb time is linear.

Thanks for giving me useful instructions, and is there a more accurate way of calculating so that after each calculation in the same case there won't be a big deviation in the index anymore.?

Tks very much mr nathan

I recommend the default for environmental settings; this is what most calculations and standards in acoustics assume unless stated otherwise.

My experience is more on the acoustic side than with Pachyderm. However, I believe Minimum Convergence is faster, while Detailed is more accurate. Given the length of calculation time, I'd use Minimum.

Hello Drum,

You might find this video https://vimeo.com/247018860 on how to adjust the parameters of the Pachyderm simulation helpful. About your first question, at school I learned that the atmospheric atenuation plays a great role in Volumes greater than 10000 m3. Your volume is 6,5 x 3,3 x4,2 = 90,09 m3, thus atmospheric attenuation should not play an important role.

The atmospheric attenuation of sound according to ISO 9613-1 amounts to 0,0019dB at 1m from the source. It changes linearly (0,19 dB attenuation at 100m).