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Complete with transmitter, radiator, receivers, and more, the LS-100 ListenIR iDSP Standard System is a good choice for mid- to large-size venues up to 100 seats in capacity.

Packaged to provide venues with an immediate assistive listening solution, the LS-100 comes with our LT-82 Stationary IR Transmitter and LA-140 Stationary IR Radiator. The heart of the system gives your venue oustanding coverage without gaps, transmitting effectively up to 3,716 m2 (40,000 ft2).

The system also includes LR-4200-IR Intelligent DSP IR Receivers, as well as an LA-381 Intelligent 12-Unit Charging Tray that allows for the system to grow with your needs.

From convention centers to theaters, courtrooms, training spaces, and more, the LS-100 is a simple and effective way to add industry-leading assistive listening to nearly any small or medium-sized space.


One (1) LT-82-01 Stationary IR Transmitter
One (1) LA-326 Universal Rack Mounting Kit
One (1) LA-140 Stationary IR Radiator
Four (4) LR-4200-IR Intelligent DSP IR Receiver
Four (4) LA-430 Intelligent Ear Phone/Neck Loop Lanyard
Four (4) LA-401 Universal Ear Speaker
One (1) LA-304 Assistive Listening Notification Signage Kit
One (1) LA-422 USB to Mico USB Cable
One (1) LA-381-01 Intelligent 12-Unit Charging Tray
One (1) LA-382 Intelligent Cable Management Unit
One (1) LA-904 Listen Dispensing Log Book


  • Pre-configured, ready-to-install system complete with transmitter, radiator, receivers, and more
  • Ideal for mid-size venues including legislative chambers, performing arts centers, classrooms/lecture halls, convention centers, and more.
  • Includes transmitter/radiator combo, several iDSP receivers, and a 12-unit charging tray
  • Crystal-clear audio performance for all listeners
  • Integrated neck loops/lanyards provide compatibility with T-coil-equipped devices
  • Designed for single-channel applications
Configurations & Architectural Specs


LS-100-01-GY ListenIR iDSP Standard System – Grey (North America)
LS-100-01-WH ListenIR iDSP Standard System – White (North America)

Architectural Specs

Furnish and install an IR wireless assistive listening system for use by the hearing-impaired. The assistive listening system (ALS) shall be capable of broadcasting on four (4) mono or stereo carriers; 2.3, 2.8, 3.3 and 3.8 MHz.  The system coverage area shall be up to 40,000 ft² (3716 m²) with single channel transmission.  The system shall have a SNR of 60 dB or better and THD of less than 2%. The system shall have an audio frequency response of 63 Hz to 15 kHz, +/- 3db.  The system shall have two (2) mixing audio inputs, one (1) balanced XLR/phone input and one (1) unbalanced stereo RCA input. The system shall have the following audio controls: input level, transmit level, contour level and stereo on/off control. The system shall have an audio processor that is capable of automatic gain control and limiting.  The system radiator(s) shall be powered via CAT-5 cabling and the RF signal shall be provided via 50 ohm coaxial cables. The system shall provide delay compensation when radiator(s) are added for additional coverage.


The system receivers shall be capable of receiving on four (4) wide band channels (carriers), Channel 1 (2.3 MHz), Channel 2 (2.8 MHz), Channel 3 (3.3 MHz) and Channel 4 (3.8 MHz).  The receivers shall be tuned to a single channel and users shall not be able to change the channel. The receivers shall have the option of being lanyard or belt clip worn and the lanyard shall incorporate an integrated neck loop for compatibility with T-coil hearing aids. The receivers shall be intelligent and provide customized audio to either earphones or the integrated neck loop based upon which is connected. The receivers shall have two (2) 3.5 mm (TRRS) connectors to drive the integrated neck loop lanyard or up to two (2) mono or stereo earphones. The receivers shall incorporate a multi-functional display (OLED) that indicates battery status, inventory number, volume level and a customizable channel name. The receivers shall employ a unique iDSPTM noise reduction technology. The receivers shall be fully programmable via PC software.  The receivers shall have a micro USB connector used for programming/setup, inventory control, charging and firmware upgrades. The receivers shall incorporate automatic battery charging circuitry and use a non-proprietary lithium ion battery. The receivers shall automatically turn on when removed from the charging device and automatically turn off when returned to the charging device.  The receivers shall have additional charging contacts to allow for multiple charging options.

The Listen Technologies products are specified.

Furnish and install the following:

Listen Technologies LT-82-01 Stationary IR Transmitter (Qty: 1 ea.)
Listen Technologies LA-326 Universal Rack Mount Kit (Qty: 1 ea.)
Listen Technologies LA-140 Stationary IR Radiator (Qty: 1 ea.)
Listen Technologies LR-4200-IR Intelligent iDSP IR Receiver (Qty: 4 ea.)
Listen Technologies LA-430 Intelligent Ear phone/Neck Loop Lanyard (Qty: 4 ea.)
Listen Technologies LA-401 Universal Ear Speaker (Qty: 4 ea.)
Listen Technologies LA-422 USB to Micro USB Cable (Qty: 1 ea.)
Listen Technologies LA-381-01 Intelligent 12-Unit Charging Tray (Qty: 1 ea.)
Listen Technologies LA-382 Intelligent Cable Management Unit (Qty: 1 ea.)
Listen Technologies LA-904 Listen Dispensing Log Book (Qty: 1 ea.)
Listen Technologies LA-304 Assistive Listening Notification Signage Kit (Qty: 1 ea.)

Q What is the purpose of Squelch?
A The purpose of squelch is to mute the audio output of your receiver when the signal from the transmitter is turned off or is too weak to be received. Without squelch you would hear radio noise in your earphone. The squelch function can be programmed to the desired setting.
Q How many carriers does the LT-82 Stationary IR Transmitter produce?
A One.
Q How many carriers can be produced simultaneously in a room?
A Four. You will need one LT-82 Stationary IR Transmitter per carrier.
Q How are radiators connected to the LT-82?
A The carrier (signal) is connected using coax cable; power is connected using standard CAT-5 cabling.
Q How is power delivered to the radiator?
A Power is delivered with CAT-5 cables (connected between the radiator and either the LT-82 transmitter or the LA-205 power supply).
Q How many radiators can be powered from the LT-82 or LA-205 power supply?
A Two.
Q How much coverage is provided with the LA-140 radiator?
A 40,000 ft² (3716 m²) single channel with LR-4200-IR/LR-5200-IR receivers or 10,000 ft² (929 m²) single channel with LR-42/LR-44 receivers
Q Does the number of carriers affect the coverage?
A Yes, for two sources (carriers), the total coverage is half. For four carriers, the coverage per carrier is one-fourth.
Q What is the purpose of the delay compensation switch?
A This switch allows you to set up delay timing in a multi-radiator system so that each radiator receives the carrier at exactly the same time. This prevents signal dropouts that can be caused by out-of-phase signals (multi-path). With Listen’s delay compensation switch, it is not necessary to cut all of your coaxial cables to the same length - your shorter runs can use shorter cables, keeping your installation clean (and cost-effective).
Q What is the warranty on the Lithium-ion battery?
A The Lithium-ion battery has a 1 year warranty. All other accessories have a 90-day warranty. Listen Warranty
Q What type of battery technology does the LR-4200 use?
A The LR-4200 uses a non-proprietary field replaceable Lithium Ion battery.
Q How long does it take to fully charge the LR-4200?
A It varies dependent on the depletion of the battery. A fully depleted battery will charge in 2.5 hours or less.
Q How many LR-4200 receivers can I use in a system?
A As many as you need, the number is endless.
Q How long will the LR-4200 run on a fully charged battery?
A The LR-4200 will run continuously for 8 hours on a fully charged battery
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