L-ACOUSTICS V-DOSC Manual Version 4
6/29/2005
Page 151 of 158
Table 20: Border (in m) Between Cylindrical (Fresnel) and Spherical (Fraunhofer) Zones
Freq
(Hz)
2 Enclosures
H=0.9 m
d
border
(m)
4 Enclosures
H=1.8 m
d
border
(m)
8 Enclosures
H=3.6 m
d
border
(m)
12 Enclosures
H=5.4m
d
border
(m)
63
No cylindrical
No cylindrical
No cylindrical
1
125
No cylindrical
No cylindrical
2
5
250 No
cylindrical
1
5
11
500 0
2
10
22
1k 1
5
19
44
2k 2
10 39
87
4k 5
19 78 175
8k 10
39 156 350
16k 19
78
311
700
Table 21: Dv - Vertical Coverage Angle in the Farfield Region
Freq
(Hz)
2 Enclosures
H=0.9 m
D
v
(deg)
4 Enclosures
H=1.8 m
D
v
(deg)
8 Enclosures
H=3.6 m
D
v
(deg)
12 Enclosures
H=5.4m
D
v
(deg)
63 -
- 124 72
125 -
125 53
34
250 125
53
26
17
500 53
26
13
8.5
1k 26
13 6.4
4.2
2k 13 6.4 3.2
2.1
4k 6.4 3.2 1.6
1.1
8k 3.2 1.6 0.8
0.5
16k 1.6
0.8
0.4
0.3
At 1 kHz a flat V-DOSC array of 8 enclosures (H=3.6 m) radiates a wavefront that is cylindrical
over a distance of 19 m. Beyond this distance, the wavefront becomes spherical, and the
coverage angle is 6° (i.e., the wavefront at 1 kHz is defined by the height of the array up to 19m
and broadens by +/-3° starting at d
border
= 19 m). For a person located less than 19m from the
sound source, frequencies below 1kHz are radiated in spherical mode with an attenuation rate
of 6 dB per doubling of distance. All frequencies higher than 1kHz propagate in cylindrical mode
with an attenuation rate of 3 dB per doubling of distance.
Figure 112: Illustration of dborder and Dv for a flat 12 enclosure array
Содержание V-DOSC
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Страница 2: ...L ACOUSTICS V DOSC Manual Version 4 6 29 2005 Page 2 of 158 ...
Страница 20: ...L ACOUSTICS V DOSC Manual Version 4 6 29 2005 Page 20 of 158 Figure 6 V DOSC System Block Diagram ...
Страница 21: ...L ACOUSTICS V DOSC Manual Version 4 6 29 2005 Page 21 of 158 Figure 7 Example LR System Configuration ...
Страница 73: ...L ACOUSTICS V DOSC Manual Version 4 6 29 2005 Page 73 of 158 Figure 49 ARRAY 2004 Geometric Data for dV DOSC ...
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Страница 133: ...L ACOUSTICS V DOSC Manual Version 4 6 29 2005 Page 133 of 158 Figure 97 V DOSC Enclosure Line Drawing ...
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