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6.5 Arraying
Ideally, only a super-high powered variable coverage speaker
would be used per channel for covering any room. Not
achievable in real life, one must resort to arrays or clusters.
Speakers are arrayed for two reasons:
- To extend the coverage of a system that has too narrow
directivity.
- To increase the sound pressure level.
The tables that follow offer directivity information for different
tight-packed array combinations, separately for horizontal and
vertical. Coverage angle, directivity index (an expression of
the directivity of an array, the more directive the higher) and
on-axis SPL (relative to a single box) results are provided.
For every model, results are provided for a number of array
boxes from 1 to 5, with splay angles from 0 to 50 degrees in
10-degree intervals. Boxes are tight packed. Results are for
the 500 to 8k Hz band, except for subs, where a one octave
100 Hz band is used.
NA
The results are calculated from polars with two degree angular and 1/24th octave
frequency resolution. Active mode was used in active/passive boxes. AUTOPOL, a
platform consisting of custom and customised hardware and software, was used for
automated high-resolution array predictions. Predictions for the 500-8k Hz band may
overestimate the coverage angles, which can reach lower values at specific frequencies.
Example. A 3x2 Compact-2 array (3 columns and 2 rows) with
40-degree horizontal and 30 degree vertical splay (shown on
the illustration).
To find out the coverage of such array, we go to the horizontal
section of the Compact-2 table and look for the 40º/3x cells,
and the 30º/x2 cells on the vertical section. The results (cells
have a grey background) show coverage angles of 165
degrees horizontal and 95 degrees vertical, and an on-axis SPL
of +1 dB (horizontal) and +2 dB (vertical) for a total on-axis
levelof+2dB(0dBhorizontal+2dBvertical)abovethe
level for a single box.
Compact-015
Horizontal
No. of elements /
Splay angle
1x 2x 3x
variable
Angle Di SPL Angle Di SPL Angle Di SPL
0º
90º 9dB +0dB 45º 14dB +5dB 15º 16dB +8dB
10º
45º 13dB +5dB 55º 13dB +6dB
20º
50º 13dB +4dB 90º 10dB +4dB
30º
75º 12dB +4dB 125º 8dB +3dB
40º
85º 11dB +3dB 160º 5dB +1dB
50º
105º 10dB +3dB 180º 4dB +1dB
Vertical (corresponds to boxes arrayed horizontally on the floor for monitor use)
No. of elements /
Splay angle
x1 x2 x3
variable
Angle Di SPL Angle Di SPL Angle Di SPL
0º
70º 11dB +0dB 25º 15dB +5dB 15º 18dB +8dB
10º
30º 14dB +4dB 45º 13dB +5dB
20º
40º 13dB +4dB 85º 10dB +4dB
30º
70º 11dB +3dB 120º 7dB +2dB
40º
90º 10dB +2dB 150º 6dB +1dB
50º
105º 9dB +1dB 175º 5dB +1dB
Compact-115
Horizontal
No. of elements /
Splay angle
1x 2x 3x 4x 5x
variable
Angle Di SPL Angle Di SPL Angle Di SPL Angle Di SPL Angle Di SPL
0º
80º 11dB +0dB 40º 15dB +5dB 20º 18dB +7dB 5º 20dB +9dB 5º 21dB +11dB
10º
40º 15dB +5dB 40º 14dB +5dB 35º 14dB +7dB 60º 12dB +7dB
20º
45º 14dB +4dB 65º 12dB +5dB 85º 11dB +5dB 115º 8dB +4dB
30º
55º 13dB +4dB 110º 9dB +3dB 135º 8dB +3dB 165º 5dB +3dB
40º
75º 11dB +3dB 150º 5dB +1dB 170º 6dB +2dB 230º 3dB +2dB
50º
100º 10dB +2dB 185º 3dB +0dB 195º 5dB +2dB 270º 1dB +1dB
No. of elements /
Splay angle
x1 x2 x3 x4 x5
Vertical
Manual del Usuario / Compact / User’s Manual