Small-area IR system ideal for use as a small-area assistive listening

Ideal Use Cases

The Williams AV IR SY1 is a small-area infrared system designed for assistive listening and private TV listening. Its stated applications include small conference rooms and hospital rooms, where an individual listener needs direct access to an audio program without changing the room’s primary sound level. Coverage depends on the selected receiver: up to 1,300 sq. ft. (120 sq. m.) with the WIR RX22-4 or 1,000 sq. ft. (93 sq. m.) with the IR RX20.

Why Choose This Model

The system combines two infrared carrier frequencies with straightforward audio and power connections. Channel 1 operates at 2.3 MHz, while Channel 2 operates at 2.8 MHz. A 3.5 mm stereo line-level input assigns Channel 1 to the plug tip and Channel 2 to the ring, with ground connected to the sleeve. This arrangement supports two-channel audio delivery through a single input connection.

The transmitter includes one yellow audio indicator per channel. Each indicator illuminates steadily when the minimum audio level is present, while a green LED shows power status. Carriers are off by default at startup and are automatically enabled when audio is detected.

Installation and Integration

Power is supplied through a Micro USB connector requiring 5 VDC at 0.2 A. The listed TFP 055 universal supply accepts 100-240 VAC at 50/60 Hz and provides a 5 VDC, 1 A USB output with international adapters. A USB-to-Micro-USB power cable is specified. Another USB power supply may be used when it provides at least 5 VDC and 0.2 A.

Optional mounting accessories accommodate several placement requirements. The STD 008 TV Top Shelf Mounting Kit uses a padded front lip that rests on the television and an adjustable rear support arm with a swivel lock. The optional BKT 024 provides omnidirectional wall or ceiling mounting. The listed operating requirement for the transmitter is 32°-122°F (0-50°C).

Performance Highlights

The transmitter uses wideband FM modulation with up to ±50 kHz deviation and 50 μS pre-emphasis. Its stated frequency response is 100-12,000 Hz, with a 70 dB signal-to-noise ratio at the onset of limiting. When audio is absent for 12 minutes, the sleep and power-save function shuts off the carrier.

Compatible receiver information includes the WIR RX22-4 and IR RX20. The specified body-pack receiver has a dual-lens detector, a four-position channel selector, a combined on/off/volume thumbwheel, and a 3-foot (0.91 m) lanyard. Its four selectable carrier frequencies are 2.3, 2.8, 3.3, and 3.8 MHz. The receiver accepts mono or stereo headphones and earphones rated from 8-32 ohms through a 3.5 mm mini phone jack. Maximum audio output is 15 mW at 32 ohms.

The receiver operates from two AA alkaline or NiMH batteries. Listed battery life is 60 hours with alkaline batteries or 30 hours per charge with NiMH batteries. A red power indicator flashes when the battery is low, and the charging contacts are intended only for use with the CHG 3512.

What Makes It Different

Automatic carrier activation and the 12-minute power-save mode reduce the need for continual manual transmitter control. Receiver-dependent coverage allows the system to be matched to the intended room, while dual transmitter channels and four receiver channel positions provide defined frequency options. The published receiver specifications also include squelch at a 28 dB signal-to-noise ratio, less than 1% total harmonic distortion for electrical response, and 50 μS de-emphasis.

A listed mono folding headphone configuration provides a 30 mm driver, 32-ohm nominal impedance, 20 Hz-20 kHz frequency response, 110 dB sensitivity at 1 kHz, and a 39-inch cord with a 3.5 mm mono plug. Its weight is 52 g, and HED 023 replacement pads are specified.

Final Assessment

The IR SY1 is a focused infrared listening solution for individual use in compact environments. Its dual-carrier transmitter, receiver-dependent coverage, visible audio indicators, automatic carrier control, universal power-supply specification, and optional placement hardware make it suitable for small-room assistive listening and private television audio applications. The system carries a stated two-year warranty and lists CE, RCM, FCC, Industry Canada, PSE, CUL, WEEE, RoHS, and CB Scheme compliance.