| Predrag |
| Member |
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| Joined: 26 May 2011 |
| Posts: 11 |
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Dear Sir,
I work as a design engineer for telecommunication installation in buildings, hotels etc.
For a long period of time I am trying to figure out how to mathematically determine ceiling speaker coverage area and number of speakers in distributed ceiling speaker design in a manner to be in correlation with the data produced by your software (Ease Address). For example:
• Room dimensions: 13m x 6m x 3m (WxDxH),
• Ceiling speaker:
BOSCH LBC 3086/41,
SPL 6W/1W (at 1kHz/4kHz) 98/90 dB,
Opening angle: (at 1kHz/4kHz, -6dB) 180o/50o,
Tap: 3W
• Software adjustment:
Overlap type: Minimum overlap,
Type: Direct SPL,
Frequency: 4000Hz,
Bandwidth: 1 octave.
Layout type: Square
Formula used for calculations (source book „Sound System Engineering“ by DON DAVIS):
Speaker distance:
S=sqrt(2)*(h-l)*tan(coverage angle/2)
Where:
h – room height in meters,
l – ear height (1,7m),
coverage angle – speaker coverage angle at 4kHz,
Number of speakers:
N= (X*Y)/(2*((h-l)*tan(α/2))2)
Where:
X – room width in m,
Y – room depth in m.
Here are the results:
Ease Address:
1) Speaker distance: 1.2m,
2) Number of speakers: 55.
My calculations:
1) Speaker distance: 0.85m,
2) Number of speakers: 106,13..
I don’t know where the problem is. Please help me?
But the most important thing to know is which formulas you use in Ease Address:
1) To determine speaker distance and
2) To determine level variation due the layout pattern,
Thank you |
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