Listen Technologies LS-91 ListenIR iDSP Level II System, LT-84-01 Transmitter, 2x LR-4200 IR Receiver, LA-422 USB to Micro USB Cable

SKU: LTLS9101 MFR: LS-91-01
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Key Features

  • Crystal-clear audio with ListenIR iDSP, enhancing every presentation moment.
  • Two LR-4200-IR receivers ensure everyone hears, improving focus and engagement.
  • Enjoy 8 hours of battery life for uninterrupted use during long meetings.
  • Easy setup with included USB cable; get your assistive listening system running quickly.
  • Universal ear speakers offer comfort; ideal for extended use in any environment.
  • Listen Technologies provides a lifetime warranty, guaranteeing lasting reliability.
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Special Order?Estimated to Ship: 09/02/2025
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Listen Technologies LS-91 Specifications

Transmitter: Audio

Transmitter: Audio

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  • Frequency Response

    20 Hz - 20 kHz (+/- 1 dB) Line Input63 Hz - 15 kHz (+/- 3 dB) System Specification (wireless end-to-end with LR-44)

  • Signal-to-Noise Ratio

    > 70 dB (SNR) Line Input> 60 dB (SNR) System Specification (wireless end-to-end with LR-44)

  • Microphone Input

    Two (2) 3.5 mm (0.14 in.) Tip/Sleeve connector, -30 dBu nominal input, +14 dB headroom, impedance 4.4k Ohms, 5 VDC bias supply

  • Total Harmonic Distortion

    < 0.1% (THD) Line Input< 2% (THD) System Specification (wireless end-to-end with LR-44)

  • Unbalanced Line Input

    Stereo/Mono Input. Two (2) Dual (RCA) Phono connectors, unbalanced, -10 dBu nominal input, +14 dB headroom, impedance 10k Ohms

  • Balanced Line Input

    Mono Input. Two (2) Phoenix Type connector, balanced, + 4 dBunominal input, +14 dB headroom, impedance 100k Ohms

Transmitter: Controls

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  • Power Switch

    Three (3) position switch - Power OFF, Power ON-Indicator Lights OFF, Power ON-Indicator Lights ON

  • Carrier Frequency Selection

    Two (2), four (4) position rotary switches (2.3 MHz, 2.8 MHz, 3.3 MHz, 3.8 MHz)

  • Level Control Knob

    Two (2) audio taper rotary potentiometer, counter-clockwise decreases input mix level, clockwise increases input mix level

Transmitter: Indicators

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  • Power Supply LED

    Green LED on in-line power supply indicates AC power is applied

  • Audio Level Indicators

    Two (2) Green LEDs, two (2) Red LEDs, Green LED indicates Audio presence and Red LED indicates peaks in the audio

  • RJ-45 Amber LED

    Solid Amber indicates carrier is present and IR is being transmitted

  • RJ-45 Green LED

    Solid Green indicates power is applied to unit, flashing indicates unit has entered power save mode

Transmitter: RF

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  • Carrier Frequencies

    2.3 MHz, 2.8 MHz, 3.3 MHz, 3.8 MHz, Selectable

  • Number of Channels

    Two (2) channels, Selectable carrier frequency

  • Frequency Accuracy

    +/- .005% stability 0 to 50 Degree C

  • Transmitter Stability

    50 PPM

  • Modulation

    FM Wideband, +/-50kHz deviation max, 50 S pre-emphasis

  • Power Save Mode

    Carrier will shut off when no audio is present for 15 minutes on both channels to preserve radiator life

  • Expansion Link Output

    Two (2) RJ-45 connectors - Provides RF Signal and Power, CAT-5e cable 24 AWG, 100 ft. maximum cable length, two (2) LA-141s per output connector

Transmitter: IR

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  • Coverage Area

    2,787 sq. m (30,000 sq. ft) single channel with LR-4200-IR/LR-5200-IR receivers or 697 sq. m (7,500 sq. ft) single channel with LR-42/LR-44 receivers

  • IR Emitter Power

    1.49 W

Transmitter: Power

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  • Power Supply Input

    100-240 VAC, 50-60 Hz

  • Power Supply Output

    12 VDC, 4 A, 48 W

  • Power Supply Connector

    2.5 mm ID barrel connector, center positive

  • Power Output

    Two (2) RJ-45 connectors. providing Power and RF signal for up to two (2) LA-141 expansion radiators on each output

  • Power Supply Type

    In-line switching mode power supply, Listen part number LA-210

  • Power Supply Line Cord

    IEC line cord, North America Type B (LT-84-01), Asia and UK Type G (LT-84-02), Euro Type C (LT-84-03), Australia Type I (LT-84-04)

Transmitter: Environmental

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  • Temperature - Operation

    14 Degree F (-10 Degree C) to +104 Degree F (40 Degree C)

  • Temperature - Storage

    -4 Degree F (-20 Degree C) to +122 Degree F (50 Degree C)

  • Relative Humidity

    0 to 95% relative humidity, non-condensing

Transmitter: Compliance

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  • Standards

    FCC part 15, ICS-03, CE, UL, CUL, C-Tick, CCC, PSE, KC, GS, RoHS, WEEE

  • Power Supply Compliance Marks

    CUL, UL, CE, CCC, C-Tick, KC, PSE, GS, FCC, RoHS

Transmitter: Physical

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  • Color

    Black with White Silk Screening

  • Counting

    Can be mounted on a wall, ceiling, or table with provided hardware (screws and hollow wall anchors not provided). Optional LA-347 Wall Box Mounting Plate is available for mounting to a standard single gang electrical box.

  • Compatibility

    LR-42, LR-44, LPT-A117, LA-141, LR-4200-IR, LR-5200-IR, LR-4200-IR-P1, LR-5200-IR-P1, LP-40-IR-01, LP-41-IR, LP-50-IR, LP-51-IR, LR-X200-IR

  • Dimensions (H x W x D)

    1.5 x 10.7 x 4.1" (3.81 x 27.2 x 10.5cm)

  • Weight

    0.8 lb (0.4kg)
    with Power Supply: 1.8 lb (0.8kg)

Receiver: Audio

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  • System Distortion

    < 2% total harmonic distortion (THD) at 80% deviation

  • Audio Output Jacks

    Two (2) 3.5 mm (0.14 in.) connectors, unbalanced, 0 dBu nominal output level, 16 mW maximum, impedance 32 ohm, accepts mono or stereo phone plug or LA-430 Intelligent Ear Phone/Neck Loop Lanyard

  • System Frequency Response

    63 Hz - 15 kHz ( +/-3 dB)

  • System Signal to Noise Ratio

    > 60 dB

Receiver: Controls

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  • User Controls

    Power on/off and volume up/down

  • Programming

    Via software and USB port, Auto Seek, Jack Sense, Squelch, Auto Power, Auto Off, Stereo, Brightness, Channel Name

  • Set-up Controls

    Press and hold up/down volume buttons for 5 seconds to enterchannel adjust, use up/down to select channel

Receiver: Indicators

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  • Display

    OLED - Channel designation, battery level, unit number, charging status, volume status

  • LED

    Flashes when batteries are low or to indicate charging, solid when fully charged

Receiver: RF

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  • Carrier Frequencies

    2.3 MHz, 2.8 MHz, 3.3 MHz, 3.8 MHz

  • Number of Channels

    Four (4) selectable channels

  • Frequency Accuracy

    +/- .005% stability 32 to 122 Degree F (0 to 50 Degree C)

  • Modulation

    FM Wideband, +/-50 kHz deviation max, 50 uS de-emphasis

Receiver: IR

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  • Coverage Area

    30,000 sq. ft (2787 sq. m) single channel with LT-84/LA-141 or 40,000 sq. ft (3716 sq. m) single channel with LT-82/LA-140

  • Squelch

    Programmable in 20 steps, automatic on loss of IR signal

  • Power Save Mode

    Turns unit off after a specified time of no IR signal, default is 30 minutes

  • Sensitivity

    Better than one (1) nW/cm2 @40 dB SNR

Receiver: Power

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  • Power Supply

    Micro USB connector, 5 V, 500 mA

  • Battery Type

    Lithium Ion

  • Battery Life

    8 Hours of typical use

  • Battery Charging Time

    Fully charged in 2.5 Hours

Receiver: Environmental

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  • Temperature - Operation

    14 to 104 Degree F (-10 to 40 Degree C)

  • Temperature - Storage

    (-)4 to 122 Degree F (-20 to 50 Degree C)

  • Relative Humidity

    0 to 95% relative humidity, non-condensing

Receiver: Compliance

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  • Standards

    FCC Part 15, ICS-03, CE, RoHS, WEEE, ADA 706, CBC 11B-706

Receiver: Physical

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  • Compatibility

    LA-140-GY, LT-82, LA-365, LA-401, LA-381, LA-405, LA-404, LA-403, LA-402, LA-380, LA-430, LT-84, LA-141, LA-382

  • Color

    Flat Black

  • Dimensions (H x W x D)

    Without Belt Clip: 3.75 x 2.0 x 0.64" (9.6 x 5.0 x 1.7cm)
    With Belt Clip: 3.75 x 2.0 x 0.80" (9.6 x 5.0 x 2.1 cm)

  • Weight

    Without Batteries: 1.9 oz (53.9g)
    With Batteries: 2.8 oz (79.4g)

About Listen Technologies LS-91

Be at the forefront of assistive listening technology with the advanced LS-91 ListenIR iDSP Level II System from Listen Technologies. This high-tech system is a comprehensive solution for small to medium-sized venues, accommodating up to 50 seats, making it an ideal choice for boardrooms, courtrooms, theaters, and educational spaces.

The LS-91 system is more than just a transmitter; it's a complete package that includes an LT-84 Transmitter/Radiator combo, multiple LR-4200-IR iDSP receivers, and a 12-unit charging tray. This innovative system is designed to meet and exceed assistive listening requirements, providing your clients with superior audio performance while ensuring your venue's compliance with assistive listening regulations.

The LS-91 system boasts a sophisticated IR wireless assistive listening system, capable of broadcasting up to two audio channels with the option of four mono carrier frequencies; 2.3, 2.8, 3.3, and 3.8 MHz. With a coverage area of up to 30,000 ft2, the system ensures clear and crisp audio transmission even in larger spaces.

The system's audio quality is exceptional, with a signal-to-noise ratio (SNR) of 60 dB or better and total harmonic distortion (THD) of less than 2%. It also features an audio frequency response of 63 Hz to 15 kHz, ensuring a wide range of sound is captured and transmitted.

The LS-91 system is equipped with two independent mixing audio inputs, each consisting of a 3.5 mm Microphone input, a balanced Phoenix type input, and an unbalanced RCA input. This allows for versatile audio input options to suit your specific needs.

The LR-4200-IR iDSP receivers are intelligent and customizable, featuring a unique iDSPTM noise reduction technology and a multi-functional OLED display that indicates battery status, inventory number, volume level, and a customizable channel name. The receivers are also fully programmable via PC software and come with a micro USB connector for programming/setup, inventory control, charging, and firmware upgrades.

In summary, the state-of-the-art LS-91 ListenIR iDSP Level II System is a comprehensive, high-quality solution for any venue needing to provide assistive listening capabilities. Its advanced features and superior audio performance make it a standout choice in the market.

Listen Technologies LS-91 Features

  • Pre-configured infrared system comes with everything you need to begin offering secure, high-quality assistive listening in your venue
  • Provides outstanding coverage up to 2,787 sq. m (30,000 sq. ft)
  • Ideal for small or medium-sized venues up to 50 seats
  • 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

Product Documents

User Manual

Key Features

  • Crystal-clear audio with ListenIR iDSP, enhancing every presentation moment.
  • Two LR-4200-IR receivers ensure everyone hears, improving focus and engagement.
  • Enjoy 8 hours of battery life for uninterrupted use during long meetings.
  • Easy setup with included USB cable; get your assistive listening system running quickly.
  • Universal ear speakers offer comfort; ideal for extended use in any environment.
  • Listen Technologies provides a lifetime warranty, guaranteeing lasting reliability.

What's in the box:

  • LT-84-01 ListenIR Transmitter/Radiator Combo
  • 2x LR-4200-IR Intelligent DSP IR Receiver
  • 2x LA-430 Intelligent Ear Phone/Neck Loop Lanyard
  • 2x LA-401 Universal Ear Speaker
  • LA-422 USB to Micro USB Cable
  • LA-381-01 Intelligent 12-Unit Charging Tray
  • Lifetime Limited Warranty