Listen Technologies LT-84-01 User Manual

ListenTech-Note

Doc. # LTN0011 Page 1 of 5 Revision: 01-23-17

ListenIR LT-84 Divisible Room Application

Overview

This tech note covers the technology and setup required to design an IR wireless assistive
listening system for divisible room applications. Using the LT-84 Transmitter/Radiator which
has four available IR channels and the iDSP LR-4200 IR Receiver featuring Auto-Seek mode,
divisible room applications for up to four sections are possible.

Required Products:

 LT-84 IR Transmitter/Radiator combo for each room.
 (Optional) LA-141 Expansion IR Radiator if additional coverage is needed for each room.
 LR-4200-IR iDSP IR Receiver. (LR-5200-IR iDSP IR Receiver optional)
 A third party audio matrix switcher.

Setup

 LT-84 Setup:

Each individual room/section must have an independent LT-84.

Each LT-84 must be set to a unique IR channel.

An audio matrix switcher is required to provide a separate audio source to each independent
LT-84 when rooms are divided and a common audio source when rooms are combined.

 LR-4200-IR Setup:

The LR-4200-IR must have Auto-Seek enabled which allows it to automatically tune to the
appropriate IR channel within the room/section.

For optimal performance, the squelch setting may need to be adjusted. When moving from
one room/section to another, the receiver will squelch and then quickly auto-tune to the next
strongest signal. If the noise level becomes higher than desired during this transition, you will
need to increase the squelch. If audio drops out during this transition, the squelch setting may
be set too high and needs to be lowered.

To enable the Auto-Seek feature and adjust squelch, the LR-4200-IR must be connected and
configured via the iDSP Software Suite. A FREE download is available at

http://www.listentech.com/support/software/.

ListenTech-Note

Doc. # LTN0011 Page 2 of 5 Revision: 01-23-17

Scenario #1: All Dividers Closed/Four Rooms Separated:

Diagram 1 below shows a four-way divisible room. In this configuration the dividers are closed,
forming four individual rooms. Each LT-84 in Rooms A, B, C and D operates independently.
Each room’s LT-84 must be set to a different IR channel.

The LR-4200-IR receiver (with Auto-Seek enabled) automatically tunes to the correct channel as
it is moved from room to room.

Example: When the LR-4200-IR receiver enters Room A it auto-tunes to Channel 1, when it
leaves the room it squelches. When the LR-4200-IR receiver enters Room B it auto-tunes to
Channel 2, etc.

Diagram 1 – Four Rooms Separated

Room A Room B

Room C

LT-84

Ch. 2

LT-84

Ch. 3

Room D

LT-84

Ch. 1

LT-84

Ch. 4

Each LT-84 requires an independent audio source routed to it via the audio matrix switcher, as
seen in Diagram 2 below.

Diagram 2 – Audio Routing with Four Rooms Separated

LT-84

Room A:

Ch. 1

LT-84

Room B:

Ch. 2

LT-84

Room C:

Ch. 3

Room A

IN 3

IN 2

IN 1

OUT 3

OUT 2

OUT 1

Control

Audio Matrix

Switcher

Room B

Room C

LT-84

Room D:

Ch. 4

IN 4

OUT 4

Room D

Audio Input Audio Output