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Hemi-directional loudspeaker | Installation and User Instructions
5
Listening area and related mounting height
Listening area
1,5 m
fig. 5. 1
Maximum sound pressure variation from centre to the edge of the listening area
Max SPL
3dB
Height
centre
diameter
[m]
[dB SPL]
[m]
4,5
97,8
3,90
5,0
96,6
4,54
5,5
95,6
5,20
6,0
94,7
5,84
6,5
93,8
6,50
7,0
93, 1
7, 1 4
7,5
92,4
7,80
8,0
91,8
8,44
8,5
91,2
9, 1 0
9,0
90,7
9,74
9,5
90,2
10,40
10,0
89,7
11,04
10,5
89,2
11,60
11,0
88,8
11,88
11,5
88,4
12,50
12,0
88,0
13, 1 2
13,0
87,3
14,38
14,0
86,6
15,62
Remarks:
•
The listening area is 1,5 m above the floor and has a circular shape.
•
The centre is the point where the loudspeaker perpendicular is positioned above the listening area.
•
The height is the distance in meters between floor and loudspeaker.
•
The total sound pressure contains the direct sound plus the first reflection of the sound on the floor measured in
dB SPL.
•
By use of the loudspeaker in indoor applications the sound pressure variation from centre to the edge of the
listening area will be equal or less. This depends on the amount of absorption and the dimension of that room.
•
The sound pressure at the edge of the listening area is the MAX SPL centre minus the chosen sound
pressure variation from centre to the edge.
•
MAX SPL is the sound pressure level at the centre of the listening area with the loudspeaker mounted on the
specified height.
•
The diameter is the line in meters from edge to centre to edge of the circular listening area.
•
The surface is the dimension in square meters of the listening area.
•
X in the table indicates that the total sound pressure drops below 75 dB SPL.
•
When two edges of listening areas reach each other, approximately +3 dB may be added to the sound pressure at
that edge region.
Bosch Security Systems | 2007-06 | F.01u.073.053
12 dB
9 dB
6 dB
3 dB
Height
Centre
Diameter
(+/-0,5dB)
6dB
(+/-0,5dB)
surface
diameter
surface
2
[m]
2
[m
]
[m
]
12
7, 1 6
40
16
8,34
55
21
9,54
71
27
10,72
90
33
11,92
112
40
13, 1 0
135
48
14,00
154
56
14,96
176
65
16, 1 0
204
75
17,26
234
85
18,40
266
96
19,56
300
106
20,70
337
111
21,86
375
123
23,00
415
135
24, 1 6
458
162
26,46
550
192
28,76
650
How to define a listening area?
1 Define the height between the loudspeaker and the
floor.
2 What is the desired maximum SPL variation from
centre to the edge of the listening area?
3 Look in the row for the specified height and in the
column for the specified SPL variation.
4 At the intersection of the row and column the
diameter and the surface is given of the listening
area.
9dB
(+/-0,5dB)
12dB
(+/-0,5dB)
diameter
surface
diameter
[m]
2
[m]
[m
]
10,40
85
14,86
12, 1 2
115
17,00
13,86
151
19,60
15,58
191
21,70
17,32
236
24, 1 6
19,06
285
26,20
20,78
339
28,28
22,52
398
30,62
24,24
461
32,98
25,98
530
35,34
27,20
581
37,70
29,44
681
40,04
30,60
735
42,40
32,00
804
43,88
33,68
891
46, 1 2
35,34
981
48,00
38,28
1151
52,26
41,60
1359
X
15dB
(+/-0,5dB)
surface
diameter
surface
diameter
2
[m]
2
[m
]
[m
]
173
20,00
314
227
23, 1 0
419
302
26,56
554
370
30,00
707
458
32,70
840
539
35,98
1017
628
39,06
1198
736
42,00
1385
854
44,00
1521
981
48,00
1810
1116
50,00
1963
1259
X
X
1412
X
X
1512
X
X
1671
X
X
1810
X
X
2145
X
X
X
X
X
| 27
18dB
(+/-0,5dB)
surface
[m]
2
[m
]
28,22
625
32,54
832
36,00
1018
39,66
1235
44,00
1521
48,00
1810
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
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