SoundPlus® 2-channel Infrared System

Product Highlights

  • Modulator/emitter combined into single operating unit
  • Resistant to high-efficiency lighting interference
  • Transmitter also available in white (WIR SYS 90 ADV WHT)
  • Meets ADAAG Guidelines
  • Made in the USA


The WIR TX90 two channel IR transmitter combines modulator and emitter technology into a single operating unit, which reduces operating cost and eliminates precious rack space. The TX90 transmitter produces a wide-angle infrared signal that concentrates the IR energy efficiently in the listening area. Operating on the 2.3-3.8 MHz bandwidth, the TX90 is less susceptible to radio and lighting interference. Each TX90 transmitter can cover up to 28,000 sq ft (2,600 sq m) in single-channel operation. The coverage area can be easily increased by connecting additional TX9 emitters. A wall/ceiling omnidirectional mount is included, and stand kits are available for portable operation.

Available options:
WIR SYS 90 ADV WHT - white emitter

System Includes

(1) WIR TX90 infrared transmitter
(5) RX18 receivers

(1) CHG 518 five bay charger

Cinemas, Simultaneous Interpretation, Audio Description, Conferences, Multi-media Rooms, Boardrooms, Courtrooms, Schools, Universities, Churches


  • Modulator/emitter combined into single operating unit
  • Resistant to high-efficiency lighting interference
  • Transmitter also available in white (WIR SYS 90 ADV WHT)
  • Meets ADAAG Guidelines
  • Made in the USA


CHG 518 Architectural and Engineering Specifications

  • The CHG 518 shall be a 5 unit drop-in battery charger and shall charge a maximum 5 x BAT AP11A NiMH battery packs while they are installed into the Williams Sound WIR RX18 style 3V receivers.
  • The charger shall be enclosed in metal and plastic measuring 12"L x 6.25"W x 1.5"H (30.48 cm x 15.875 cm x 3.81 cm). The unit shall weigh 1.04 lbs (.47 kg) without power supply, 1.6 lbs (.725 kg) shipping weight.
  • Each bay on the charger shall have a red LED indicating charging status. The LEDs shall be on continuously during charge and after six hours will turn green indicating battery is fully charged. The charger will monitor the state of the batteries and will recharge them if needed when kept in the charger*.
  • The charger CHG 518 shall be powered by an external power supply via a DC barrel connector. The CHG 518 shall be supplied with a piggy-back connector enabling up to three chargers to be powered by one power supply. The charger shall be RoHS compliant and be covered by a one-year parts and labor warranty (90 days on cable and power supply).
  • The charger shall be the Williams Sound, model CHG 518.

CHG 518

Dimensions: 12"L x 6.25"W x 1.5"H (30.48 cm x 15.875 cm x 3.81 cm)
Weight: 1.04 lbs (.47 kg) excluding power supply
Color: Black metal and plastic
Power Supply Input: 120 VAC
Power Supply: 100-240V / 12VDC TFP 043
Unit Capacity: 5 Units
Indicators: Individual Charging Indicators: Red LEDs
Warranty: 1 year (90 day warranty on cables and power supply)
Approvals: WEEE, RoHS

Note: Charging specifications are based on Williams Sound, rechargeable NiMH battery, BAT AP07D


*Due to a component substitution there are two versions of the CHG 518. Serial numbers 0654 to 0853 will NOT monitor the battery state and will charge on a six hour timer. Serial numbers before and after this sequence will monitor the battery state.

IDP 008

10-3/8" (L) x 6-¼" (W) x 1/8" (H)

WIR RX18 Architectural and Engineering Specifications

  • The receiver shall be an under-chin stetho style with an IR detector lens in the face of the unit.
  • The receiver shall have a rotary type volume control and the power switch shall be built into the arms of the unit so it will automatically shut off when not in use.
  • The receiver shall operate for seven hours per charge with the BAT AP11A NiMH battery pack.
  • The receiver shall be housed in a black and grey plastic case.
  • The receiver shall have a three position selector switch for 2.3 MHz, stereo or 2.8 MHz modulated IR signals.
  • The receiver shall provide 120dB SSPL90 output.
  • The system electrical frequency response shall be 200Hz to 8kHz and the S/N ratio shall be 60dB at 10m.
  • The receiver shall have CE, RoHS and WEEE approval and be covered by a five-year parts and labor warranty (90 days on battery pack).
  • The receiver shall be the Williams Sound model WIR RX18.



2.0 oz (56 g) with battery

Material and Color:

ABS plastic, Black and Grey

Battery Type, Life:

BAT AP11A NiMH Battery Pack, 7 hours

Operating Range:

Up to 3,063 sq ft (285 sq m) when used with the TX9 emitter or TX90 transmitter in single-channel mode

Up to 1,000 sq ft (93 sq m) when used with the TX75 in single-channel mode

Modulation Frequency:

2.3 MHz or 2.8 MHz or stereo

Frequency Response:

200 Hz to 8 kHz, ± 5 dB

Signal to Noise Ratio:

60 dB at 10 m


Volume control thumbwheel

3-position selection switch (2.3 MHz, 2.8 MHz, stereo)

Acoustic Output:

120 dB MAX SSPL90 with 2 cc coupler


Compatible with 2.3 MHz and 2.8 MHz IR transmitters, WIR TX900 and WIR TX925 systems

Battery Charger:

CHG 518

Power Switch:

Built into receiver “arms"

Ear pads:

Uses EAR 240 silicon eartips




5 years (90 days on battery)

WIR TX90 Architectural and Engineering Specifications

  • The infrared transmitter shall consist of an all-in-one modulator and emitter operating on switchable carrier frequencies of 2.3/2.8 MHz or 3.3/3.8 MHz. The carrier frequency shall use 50 kHz deviation and 50μs pre-emphasis.
  • The transmitter shall have a range of up to 28,000 ft2 (2,600 m2) in single channel mode when using the RX22-4 receiver. The transmitter shall be contained in a metal housing with a durable plastic lens. The transmitter shall be convection cooled without fans. The transmitter shall include an omni-directional mounting bracket for permanent installations. Additional brackets shall be available for different mounting options.
  • The transmitter shall provide two channels of selectable carrier frequencies: CH A: 2.3/2.8 MHz or CH B: 3.3/3.8 MHz. Two transmitters used in tandem shall provide up 4 simultaneous channels.
  • The transmitter shall have two Phoenix Contact® connectors on the back for balanced or unbalanced line input. All controls and indicators shall be accessible on the bottom of the panel of the transmitter.
  • The transmitter shall have three application presets: Music, Hearing Assistance and Voice accessible by thumbscrew adjuster.
  • There shall be a 3.5mm stereo headphone jack for monitoring the processed audio before being transmitted.
  • Two BNC (50Ω) baseband output jacks shall be provided on the back panel for more coverage needs. The TX9 emitter panels must be used with the TX90 transmitter via RG58 coax cable.
  • The transmitter shall be powered by an external 24VAC, 50-60 Hz, 35VA power supply. The power connector shall be a three pin Molex type. Additional emitters shall require individual external power supplies.
  • The transmitter shall be covered by a five-year warranty on parts and labor.
  • The transmitter shall be the Williams Sound model WIR TX90.


Dimensions, Weight:

11.25" W x 6.25" H x 2.125" D (28.6 cm x 15.9 cm x 5.4 cm), 1.8 lbs (0.8 kg)


Black with white legends, black acrylic lens (optional white enclosure available)

Power Supply:

Wall Transformer, 24 VAC, 50-60Hz, 35 VA, 3-pin MOLEX Connector

North America: TFP 010, UL/CSA

Europe: TFP 027-01, 2-pin Schuko plug, CE

UK: TFP 027-02, 3-pin UK plug, CE

Power Cable:

NEC Class 2 wiring, two-conductor, 18 ga., 200' (61m) max. length


FM Wideband, +50kHz deviation max., 50uS pre-emphasis

Carrier Frequency:

Channel A: Selectable, 2.3/2.8 MHz,
Channel B: Selectable, 3.3/3.8 MHz

Emitter IR Power:

3.5 watts

Coverage Area:

28,000 sq. ft. (2600 sq. m) in single channel mode when using the RX22-4 Receiver

18,000 sq. ft (1700 sq. m) in two channel mode when using the RX22-4 Receiver

11,000 sq. ft (1000 sq. m) in four channel mode when using the RX22-4 Receiver

3,500 sq. ft (325 sq. m) in single channel mode when using the RX15-2 Receiver

3,063 sq. ft (285 sq. m) in single channel mode when using the RX18 Receiver

Signal-to-Noise Ratio:

>75 dB, +3 dB

Frequency Response:

80 to 15,000 Hz, electrical response

Total Harmonic Distortion:

Less than 0.2%, electrical response at 1kHz


Music preset 1:1, Voice preset 1.5:1, Hearing Assist preset 2:1

Auto Carrier Shut-Off:

20 minute timer shuts off carrier when no audio is present



TX90 Bottom View

Power Indicator:


Audio Volume Level Controls:

CHA and CHB Input Level, press to select, 28 dB adjustable range

Audio Indicators:

CHA and CHB Audio Level, yellow LED, flash

Carrier LEDs:

2 green LED carrier "on" indicators

Phones Output:

3.5mm TRS headphone jack. CH A tip, CH B ring on jack, 32 ohm headphone (min)

Application Preset:

Music, Voice, Hearing Assist. Frequency response; Music: Flat; Voice: Mid-range boost; Hearing Assist: High frequency boost

Tone Control:

Press to select, 21 dB adjustable range (1 kHz between low boost/hi-cut and low cut/hi boost).



TX90 Back Panel

Power Input:

3-Pin Molex, 24 VAC, 50-60 Hz, 35 VA

Audio Input Connector:

CH A and CH B, 3 wire Phoenix

Input Level:

Balanced or unbalanced, 316 mVRMS (-10dBV) nominal, 5.7k input impedance; max input (over volume range) -21 to +7 dBV.

Baseband Output:

BNC, 50 Ω, for use with TX9 only

Baseband Cable:

RG 58 Coax, BNC connectors, maximum 1000’ (300m) length

Operating Requirements:

0-50º C (+32°F to 122°F) ambient temperature, non-condensing, non-corrosive atmosphere

Mounting Kits:

Wall or Ceiling Mount: BKT 024 Omnidirectional mount;
Optional: Tripod Stands: SS-11 or SS-6


5 years on transmitter, 90 days on accessories



Compatible Receivers:

WIR RX22-4 Four-Channel Receiver
WIR RX15-2 Two-Channel Receiver
WIR RX18 Two-Channel Receiver

Notes: Specifications: Single end input, volume & tone controls at mid point, 1 kHz, "Music" Preset

Other Models

WIR SYS 90 ADV WHT - white emitter

Accessories for WIR SYS 90 ADV SoundPlus® Two-channel Infrared System

SS-6 Floor stand kit


Download/View Name Type Language
WIR SYS 90 ADV Specifications Specifications English
Infrared Brochure - High Res Brochures English
Infrared Brochure - Low Res Brochures English
SoundPlus™ 2-channel Infrared Listening Systems Manuals English


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