LBC 3200/00
XLA 3200 Line Array Loudspeakers
LBC 3200/00, LBC 3201/00, LBC 3210/00
en Product information and installation manual, please see
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Table of contents
1
Installation 4
2
Listening area and related mounting height for XLA3200/00 8
3
Listening area and related mounting height for XLA3201/00 11
4
Listening area and related mounting height for XLA3210/00 14
5
Technical data 17
5.1 Additional technical data 20
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2017.01 | |
Installation
1
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Listening area and related mounting height for
XLA3200/00
Determining mounting height and angle for the LBC3200 loudspeaker array:
1. Determine the dimensions of the desired ‘listening area’ (a horizontal plane at the level of
the listeners’ ears – refer to the dashed line in figure 1).
2. Determine the angle at which the loudspeaker array is to be mounted. The array is
designed to beam sound just above the listeners’ heads, and it is recommended not to
exceed an angle of 6”. There are two approaches, each with specific pros and cons.
– Approach 1: Maximized listening area
– When a large listening area is desired, an angle of around 3” is recommended (see figure
1). Note that when walking away from the loudspeaker array, the sound pressure level
will decrease by an amount that depends on the room reverberation. To hear high tones
clearly, the listener should be able to see the loudspeaker array.
– Approach 2: Minimized sound pressure level variation
– When less sound pressure level variation is desired, an angle of 5º is recommended. Note
that this reduces the size of the total listening area compared to approach 1, and that the
space very close to the loudspeaker array (‘A’ in figure 2) is not part of the listening area.
Diagram 1 shows the relationship between ‘A’ and the mounting height of the
loudspeaker array when using a 5” installation angle.
1. After selecting the most appropriate approach (mounting angle), the mounting height of
the loudspeaker is determined by focusing the 0º-axis of the loudspeaker array to the
desired position just above ear level of the furthest listener. This can be adjusted by
mounting the loudspeaker higher or lower on the wall.
Now you can mount the loudspeaker array for optimal acoustic performance.
2
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Installation questions and answers:
– May I install the LBC3200 loudspeaker array the same as LBC3210 or LBC3201?
– This loudspeaker array is designed for small and medium indoor environments. The
optimal acoustical performance of this loudspeaker array is obtained by beaming the
sound just above the listeners’ heads. When this loudspeaker array is mounted as the
LBC3210 or LBC3201, a very small listening area results. This is also the reason for not
using an angle greater than 6º.
– If I cannot see the loudspeaker array, does it mean that I cannot hear high tones?
– You can compare high tones with light. When something is between you and the light
source, you do not see the light source with its full power. We call this shadow. When a
lot of people are sitting between you and the loudspeaker, you are sitting in the sound
shadow. We experience that as a reduction of high tones.
Background information:
– Because of the many installing angles it is difficult to give a defined shape of the radiated
sound from the loudspeaker array.
– By installing the loudspeaker array at a small angle, a (very) large listening area can be
reached. Depending on the amount of reverberation in the room and the sound shadow
(people or objects in front of a listener who are blocking the direct sound source) the
speech intelligibility on a far position may be low. In these situations, it is better to use
more loudspeaker arrays to split the listening area.
– When you move further than the maximum position of the listening area (more than the
maximum distance from the loudspeaker array), only the sound pressure level will
decrease. There is almost no tone height variation. The decreasing of sound pressure
level depends strongly on the reverberation in the room.
– When you are too close to the loudspeaker array (less than the minimum distance from
the loudspeaker array) and are using the 5º approach a decline of the high tones will very
soon occur.
– Because the loudspeakers are designed to beam the sound just above the listeners’
heads, it is better not to mount the loudspeakers too high above the listening area.
– To determine exactly where the edges of the listening area are in your situation, you have
to carry out a practical test at the location where the loudspeaker array is installed. This
is a job for an experienced listener with well-trained ears. To do so, put pink noise
through the loudspeaker array. It is better to reduce the lower tones for this test, as they
do not contribute to speech intelligibility. Walk around in the listening area and listen to
the high tones. The places where the high tones decrease rapidly are the edges of the
listening area.
XLA 3200 Line Array Loudspeakers
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Figure 1: side view of loudspeaker array radiation mounted to the wall with a small angle
Figure 2: side view of loudspeaker array radiation mounted to the wall with a 5º angle
Diagram 1: relation between listening area distance and loudspeaker array
10
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Listening area and related mounting height for
XLA3201/00
How to use this mounting method:
1. Determine the dimensions of the desired ‘listening area’ (a horizontal plane at the level of
the listeners’ ears – refer to the dashed line in figure 1).
2. Measure the maximum distance from loudspeaker array to the last listener in the listening
area (corresponding to ‘B’ in figures 1, 2 and 3).
3. Refer to diagram 1, and trace upwards from the maximum distance on the horizontal axis.
From the vertical intersection with diagonal B-line, you go horizontal to the vertical axis.
The X-value (height of loudspeaker array mounting bracket above the listening plane, ‘X’
in figure 1) is standing on this axis. The horizontal intersections with other diagonal lines
provide information about the dimensions of the listening area. These numbers are
related to figures 2 and 3 (see also example below).
4. Figure 2 shows the 1 kHz octave shape radiated by the loudspeaker array and figure 3
shows the 4 kHz octave shape radiation. The listening area with the optimal acoustic
performance is in these shapes. Ensure the 4 kHz shape with the dimensions obtained
using diagram 1 adequately covers the desired listening area.
5. If the desired listening area is covered by the 4 kHz shape, the X-value on the vertical axis
shows at what height the loudspeaker array must be mounted above the listening plane.
Note that the loudspeaker array must be mounted at an angle of 8”at the chosen height!
Now you can mount the loudspeaker array for optimal acoustic performance.
Diagram example:
The maximum distance from loudspeaker array to last listener is 15 m. Tracing upwards from
the 15 m point on the horizontal axis of diagram 1 to the diagonal B-line and then sideways to
the vertical axis, the intersections with the other diagonal lines provide dimensions of the
listening planes. In this example:
F-line (listening plane side length of 4 kHz) = 11.1 m
C-line (listening plane length) = 11 m
E-line (half width listening plane of 4 kHz) = 9.3 m
A-line (minimum distance to listening plane) = 3.9 m
On the vertical axis, the X-value (the height between the listening plane and loudspeaker array
mounting bracket) is 1.8 m.
Installation questions and answers:
– The desired listening area is too large and does not fit in the 4 kHz shape.
– Try a different loudspeaker array mounting height or use more loudspeaker arrays to get a
larger listening area.
– Why use an angle of 8º for the loudspeaker array?
– The radiated shapes shown in figures 2 and 3 with the dimensions in diagram 1 are only
valid when the loudspeaker array is mounted at an angle of 8º. Only this situation
provides constant sound pressure level and frequency response (constant directivity) in
the listening area.
– Can I use the loudspeaker array with another angle?
– You can use the loudspeaker arrays with another angle but you will not get the optimum
acoustic performance. For example, greater sound pressure level variation will be audible
in the listening area. The values in diagram 1 are not valid for other angles. It is
recommended never to use an angle greater than 8º.
– The loudspeaker array cannot be mounted as high as desired.
3
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