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Lodspeakers under the listening area
PostPosted: Fri Nov 25, 2005 8:37 am Reply with quote
Elena_Dm
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Joined: 25 Nov 2005
Posts: 1
Location: Moscow




Hello!
I have a problem when loudspeakers are located on the audience area or under it. In that case SPL on the area is 0dB. I deal with a configuration when subwoofers are on the floor and I don't know how to calculate SPL at low frequences without displacing subwoofers.
Maybe someone had solved this problem?
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PostPosted: Fri Nov 25, 2005 3:13 pm Reply with quote
Bruce
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Joined: 19 Apr 2005
Posts: 459
Location: Minneapolis, MN, USA




Hello and welcome to the forum,

I have used two approaches to solve this:

  1. Place the subwoofers the same amount above the Aud. Area as they are mounted below the Aud. Area in real life.

  2. Map to the face that is beneath the Aud. Area instead. This is particularly useful when you have some loudspeakers below and some above the Aud. Area like in a large hall with a balcony.

The approach I use depends on the circumstances and what it is that I am looking for.

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Bruce C. Olson
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PostPosted: Mon Nov 28, 2005 11:39 am Reply with quote
arkie
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Joined: 04 May 2005
Posts: 13




For floor subwoofers I usually build a special area(s) about 0.1m over the floor face.
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Re: Lodspeakers under the listening area
PostPosted: Mon Jan 30, 2006 9:49 am Reply with quote
Peter Patrick
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Joined: 26 Apr 2005
Posts: 33
Location: Toowoomba - AUSTRALIA




Elena_Dm wrote:
Hello!
I have a problem when loudspeakers are located on the audience area or under it. In that case SPL on the area is 0dB. I deal with a configuration when subwoofers are on the floor and I don't know how to calculate SPL at low frequences without displacing subwoofers.
Maybe someone had solved this problem?


Hello,
I have never bothered to try to map sub woofer SPL in EASE models.
The wavelength of sounds produced by subwoofers is so large it tends to make the room behave like a small room ... that is ... there are standing waves and room modes present.
These mean that none of the regular calculationc in EASE are necessarily applicable .... which is a major part of the reason EASE does not calculate SPL below 100 Hz.
EASE calculations are essentially "Large Room" calculations which depend on sound moving in a Ray like pattern.
When sound moves as it does at sub woofer frequencies... like waves in a ripple tank, the whole scenario changes.

It's also my belief that regular SPL dispersion and SPL tests are not of great value for sub-woofers because Sound Engineers will set the Sub woofer level where it "feels good". Testing sub woofers frequency response is an excercise in futility indoors. What value then can we place on a model prediction. ??

So then we are left with the problem of any ordinary loudspeaker below the mapping plane.

I suggest using Bruce Olson's approach because the errors involved are so small there is no benefit in resolving them.
Very Best Regards

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Peter J. Patrick
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