
#1
how to predict the behaviour of a Gobo
Is it possible to predict the behaviour of a porous absorber used as a gobo somewhere in the room?
I use this porous absorber calculator:
http://www.acousticmodelling.com/porous.php
If I try to predict the behaviour of the absorber placed on a boundary (with or without a moderate air gap) I obtain a good and smooth curve of the absorption coefficient throughout the entire (effective) range of the absorber.
But if I set the air gap at a value of 3000mm ( 3 mt) I obtain an uneven curve, something like a lot of comb filtering. Is this irregular behaviour what really happens when I use a gobo in the middle of a room, or am I using badly the 'air gap' parameter?
According to the results, moreover, if I increase the thickness of the absorber in the calculator (let's say from 180mm to 240mm) the frequency response become smoother (always uneven, but smoother).
I use this porous absorber calculator:
http://www.acousticmodelling.com/porous.php
If I try to predict the behaviour of the absorber placed on a boundary (with or without a moderate air gap) I obtain a good and smooth curve of the absorption coefficient throughout the entire (effective) range of the absorber.
But if I set the air gap at a value of 3000mm ( 3 mt) I obtain an uneven curve, something like a lot of comb filtering. Is this irregular behaviour what really happens when I use a gobo in the middle of a room, or am I using badly the 'air gap' parameter?
According to the results, moreover, if I increase the thickness of the absorber in the calculator (let's say from 180mm to 240mm) the frequency response become smoother (always uneven, but smoother).