Rated 4.9 (120 reviews)
The Listen Technologies LT-84-02 is a two-channel ListenIR infrared assistive listening transmitter and radiator in one unit, supplied with a UK power lead. One channel covers up to 2,787 m² with LR-4200-IR receivers, and up to four LA-141 expansion radiators can be added. Because infrared stays in the room it suits courtrooms, council chambers, boardrooms, theatres, classrooms and multi-room venues where audio must not leak next door.
2
Channels
2,787 m²
Coverage, 1 channel
4
Carrier frequencies
Up to 4
LA-141 expansions
Coverage figuresThe 2,787 m² figure is for one channel with LR-4200-IR or LR-5200-IR receivers. Older LR-42/LR-44 receivers give 697 m², and two-channel use or obstructions reduce usable coverage.
Infrared needs line of sightIR light stays inside the room, which keeps audio private and lets adjacent rooms run separate systems, but receivers need a view of a radiator. Plan radiator positions for large or obstructed rooms.
Features
Transmitter and radiator in one unit
Two channels, each set to one of four carrier frequencies
Each channel accepts mic, stereo RCA (summed) and balanced Phoenix line inputs
Front level controls with audio presence and peak LEDs
Up to four LA-141 expansion radiators, with delay compensation to avoid dropouts
Single CAT-5e cable carries power and signal to each expansion radiator
Power save mode switches the carrier off after 15 minutes of silence
Mounting hardware for wall, ceiling or table supplied
Specifications
| Channels | 2, each on a selectable carrier: 2.3, 2.8, 3.3 or 3.8 MHz |
| Coverage | 2,787 m² single channel with LR-4200-IR/LR-5200-IR; 697 m² with LR-42/LR-44 |
| IR emitter power | 1.49W |
| Mic inputs | 2x 3.5 mm TS, -30 dBu nominal, 4.4 kohm, 5V bias |
| Unbalanced line inputs | 2x stereo RCA pairs, -10 dBu nominal, 10 kohm |
| Balanced line inputs | 2x Phoenix, +4 dBu nominal, 100 kohm |
| Frequency response | 20 Hz to 20 kHz (±1 dB) line input; 63 Hz to 15 kHz (±3 dB) system |
| Signal-to-noise ratio | >70 dB line input; >60 dB system |
| Modulation | Wideband FM, ±50 kHz deviation, 50 µs pre-emphasis |
| Expansion outputs | 2x RJ45 (power and RF), CAT-5e 24 AWG, 30 m max, 2 LA-141 per output |
| Power save | Carrier off after 15 minutes without audio on both channels |
| Power supply | 100 to 240V AC in, 12V DC 4 A out, UK Type G line cord |
| Dimensions (H x W x D) | 381 x 272 x 105 mm |
| Weight | 0.4 kg (0.8 kg with power supply) |
| Mounting | Wall, ceiling or table (hardware supplied); LA-347 back box plate optional |
| Operating temperature | -10 to 40°C |
