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tnargs 16th January 2013 04:22 AM

Soundwave theory question: reflection
 
Hi, is anyone able to help me grasp a particular question please.

If a 300mm (1 foot) diameter column is pressed up against the front of a loudspeaker (or just clear) ----

1--- which wavelengths reflect straight back to the speaker?

2--- which wavelengths are scattered widely?

3--- which wavelengths are relatively unaffected and pass right around the column?

4--- is there a transition region between 2 and 3 and if so, what happens in it?

I would like to better understand the relationship between deflector size and sound wave behaviour.

Thank you

davidsrsb 16th January 2013 04:55 AM

How big is the driver?
There is open source software to model this at
AcouSTO - Acoustics Simulation TOol - Homepage
but not easy to use

tnargs 16th January 2013 11:22 AM

Well it is an in-principle question, so I will take any driver size you care to assume. thanks

tnargs 16th January 2013 11:23 AM

I haven't seen that tool before. I will take a look.

Any generalised answers would also be much appreciated.

Ron E 16th January 2013 06:54 PM

I think you will find that this is much easier to measure than calculate, and it depends on your observation point. Probably the best way to resolve this qualitatively is with a java ripple simulation calculator - do a search.

tnargs 16th January 2013 07:10 PM

Thanks Ron, I'll have a look.

I wonder if there is a general rule like "if the wavelength is more than twice the column diameter, there is little to no scatter of the sound"?

davidsrsb 16th January 2013 10:42 PM

The behaviour of a plane wave passing your column is fairly easy to predict. You have a far more complex situation as the column is close to the source and gives early reflection back to the driver

Ron E 18th January 2013 10:27 PM

Quote:

Originally Posted by tnargs (Post 3328852)
Thanks Ron, I'll have a look.

I wonder if there is a general rule like "if the wavelength is more than twice the column diameter, there is little to no scatter of the sound"?

It's probably closer to 6 times...

tnargs 19th January 2013 03:14 AM

Thanks Ron and David, I will continue to study it.

chris661 19th January 2013 10:59 PM

Would a Hornresp simulation throw out anything useful?


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