Commercial-grade large-area infrared transmitter system

The Williams AV IR SY21 D is a commercial-grade, large-area Dante infrared system built around an IR+ transmitter and array, with bodypack receivers for audience access. Intended for ADA and IBC audio compliance applications, it provides coverage of up to 18,000 square feet in single-channel mode. The system combines rack-mounted audio processing, CAT5e emitter distribution, receiver support, and browser-based configuration.

Ideal Use Cases

This system is designed for large venues that require infrared audio coverage and support for ADA and IBC audio compliance. Its stated coverage area makes it suitable for installations extending up to 18,000 square feet in single-channel mode. Selectable carrier frequencies and two audio inputs also support applications that need separate audio channels or stereo receiver operation.

Why Choose This Model

The IR SY21 D combines wide-area infrared transmission with flexible professional audio connections. Two combination 3-pin XLR and 1/4-inch TRS inputs accept balanced or unbalanced line-level signals as well as balanced or unbalanced microphones. Selectable phantom power supports compatible microphones. Two front-panel 1/4-inch headphone outputs provide direct monitoring of channel A and channel B.

DSP-based processing includes selectable compression ratios of 1:1, 1.5:1, and 2:1, along with high-pass and low-pass filter frequency control. An adjustable carrier shut-off timer stops the carrier when audio is absent, while a 400 Hz internal test tone supports setup and diagnostics.

Installation and Integration

The modulator occupies one rack unit and measures 19 inches wide by 1.75 inches high by 8.2 inches deep. Four RJ-45 emitter output ports connect through CAT5e cable. A single cable carries +48 VDC power, RS-485 communication, and baseband signals for infrared transmission. The emitter receives 48 VDC from the IR M1 through this connection.

Remote configuration is available through an embedded website, including adjustment of the automatic carrier shut-off timer. Dual infrared test LEDs support receiver testing, monitoring, and audio-signal testing. The international desktop power supply accepts 110-240 VAC at 50-60 Hz and provides +48 VDC at 0.75 A through a center-positive output. The system is specified for operation from 0-50 degrees C in a non-condensing, non-corrosive atmosphere.

Performance Highlights

The system uses FM wideband modulation with +50 kHz deviation and 50 uS pre-emphasis. Carrier frequency pairs are selectable between 2.3/2.8 MHz and 3.3/3.8 MHz. Electrical frequency response is rated from 40 to 16,000 Hz at +1 dB/-3 dB, with a typical signal-to-noise ratio of 67 dB and total harmonic distortion below 2 percent.

The bodypack receiver operates at 2.3 MHz, 2.8 MHz, or stereo and includes a three-position selection switch, volume thumbwheel, and power slider. It uses a LiPo battery rated for eight hours and provides a 3.5 mm stereo headphone jack. Receiver acoustic output is specified at 120 dB maximum SSPL90 with a 2 cc coupler.

What Makes It Different

The IR SY21 D brings signal transport, power, control communication, and infrared baseband distribution together over CAT5e. This reduces the number of separate connections required between the IR M1 and compatible emitter hardware. Integrated channel monitoring, internal diagnostics, DSP processing, automatic carrier control, and embedded web configuration give installers multiple ways to configure and verify the system.

The bodypack receivers are compatible with 2.3 MHz and 2.8 MHz infrared transmitters and support stereo selection. Listed approvals include CE, FCC, RoHS, RCM, WEEE, CB Scheme, ISED, and VCCI.

Final Assessment

For large-area infrared audio installations, the Williams AV IR SY21 D provides a focused combination of up to 18,000-square-foot single-channel coverage, Dante system capability, professional microphone and line inputs, CAT5e emitter connectivity, DSP processing, remote configuration, and rechargeable bodypack receivers. The modulator carries a two-year warranty, while accessories are covered for 90 days.