Listen LT-82 - Designing a System

l
7
Up to four LT-82 transmitters can be interconnected to create up to a four
channel system
Each radiator requires one RF (RG-58 coax) connection and one power
(CAT-5) connection
Listen Technologies has provided mounting hardware for most LA-140
mounting situations
It is possible that the RF signal arrives to dierent radiators at dierent times
As the number of channels increases, the eective radiated coverage declines
The coverage patterns provide coverage of the system assuming no reection
The maximum length of CAT-5 power cable
The maximum length of coaxial RF cable
Designing a System
You will need to order one LT-82 transmitter for each audio channel. The Listen system can deliver
up to four audio channels simultaneously.
1
Determine the number of audio channels
You should either measure the room or use the architect’s plans to obtain this information.
2
Determine the room size and shape
Complete the room layout worksheet found in the nal section of this guide placing the location of the
transmitters, power supplies and radiators using the worksheet key. The following factors will determine
the coverage of the room.
3
Complete the room layout worksheet
3A
Except in small rooms it is recommended that at least two radiators be used to ensure good coverage and
minimal shading. Listen Technologies radiators (when used with Listen Technologies ’ LR-42 and LR-44
receivers) will cover approximately 10,000 ft
2
(929 m
2
) for one channel as indicated in the diagram below
(note the coverage decreases as the number of channels goes up). For two channels, one radiator will
cover 5,000 ft
2
(465 m
2
) and for four channels, one radiator will cover 2,500 ft
2
(232 m
2
). When using
LR-4200-IR/LR-5200-IR receivers, the approximate line-of-sight coverage increases to 40,000 ft
2
(3716 m2)
for one channel.
Number of radiators and location
You should use the above coverage pattern to determine coverage of each radiator in your system, not by trial
and error. The radiator will be stronger when new and therefore is under-rated by 40 percent and the coverage
pattern above accounts for this. 40 percent degradation will occur after approximately 8,000 operating hours.
10
10
0
0
30
20
50
40
40
50
20
30
10
20 30 40 50 60 70 80 90 100 110 120 130 140 150
1 TX2 TX4 TX
Horizontal Plane Footprint Pattern (feet)
Coverage
pattern shown
in feet