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Old 13th September 2007, 05:25 AM   #1
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Default Why angular frequencies in Leach's calculations ?

I have been reading Dr. Leach's paper and have difficulty with the concept of angular cutoff frequency.

Why do we have to use the angular cutoff frequency and what will be the effect in the final design ?
In most of the other formulas, I have been using the cutoff frequencies, Fl, Fh, Fc.

If I undestand properly, Leach suggest we have to use 2πFl, 2πFh, 2πFc to calculate the horn parameters.
Does this apply only to folded horns ? Are there times where we should use less then 360 degrees ?
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Old 13th September 2007, 05:44 AM   #2
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angular frequency = 2 pi f

it is used because it makes the equations easier to manipulate.

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Old 13th September 2007, 08:15 AM   #3
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It's also worth pointing out that Leach's math works on a few assumptions, one of which is maximum efficiency (or as close as you can reasonably get) is the principle goal / desire. No folds are assumed in his equations, which are really aimed at 'proper' horns (i.e. front loaded) though they're frighteningly effective for BLHs as well.
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Old 17th September 2007, 10:51 PM   #4
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It still does not explain why we use the angular frequency.
There is rotation in this equation and I do not understand where the movement of the membrane is tranfered in a rotational movement, unless this movement refers to the omnidirectional movement of a sound wave.

Maybe I should read more about acoustics to better understand these priciples. Any good web references to help me understand ?
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Old 18th September 2007, 05:38 AM   #5
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Quote:
Originally posted by lowtherdream
It still does not explain why we use the angular frequency.
It is all about the math. The change from cartesian co-ordinates makes any math with sines/cosines MUCH easier to manipulate.

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