SoundPlus® 2-channel Infrared System

Product Highlights

  • Modulator/emitter combined into single operating unit
  • Stylish, NEW WIR RX15-2 headset-style IR receivers
  • Resistant to high-efficiency lighting interference


This infrared listening system ensures direct, clear delivery of your message without sacrificing security.  The TX90 two-channel IR transmitter combines modulator and emitter technology into a single operating unit, which reduces operating cost, eliminates the need for rack space and eases set-up. Resistant to high-efficiency lighting interference. Up to 28,000 sq ft (2,600 sq m) coverage in single-channel operation with the WIR RX22-4N receiver. (Coverage area can be easily increased by connecting additional TX9 emitters.)  This system features our stylish, NEW WIR RX15-2 headset-style, infrared receivers.  Wall/ceiling omnidirectional mount is included.  Stand kit is available for portable operation.

Available options:

WIR SYS 91V WHT - white transmitter


System Includes

  • (1) WIR TX90 infrared transmitter
  • (3) WIR RX15-2 infrared receivers
  • (1) WIR RX22-4 infrared receiver
  • (2) NKL 001 neckloops
  • (1) HED 021 headphone
Cinemas, Simultaneous Interpretation, Audio Description, Conferences, Multi-media Rooms, Boardrooms, Courtrooms, Schools, Universities, Churches


  • Up to 28,000 sq ft coverage (with WIR RX22-4N receiver) in single-channel mode
  • Transmitter also available in white (WIR SYS 91V WHT)
  • Meets ADA accessibility guidelines
  • Made in the USA


BAT 001-2

Alkaline, 1.2 Volt

HED 021


Mono, folding headphone


3.5mm mono



Driver Size

30 mm

Nominal Impedance


Freq. Response

20 - 20kHz



Max Power Input

100 mW


110 dB @ 1kHz

Replacement Pads

HED 023 (one pair)

IDP 008

10-3/8" (L) x 6-¼" (W) x 1/8" (H)

WIR RX15-2 Architectural and Engineering Specifications

  • The receiver shall be a headset style with IR detectors positioned on top of each individual earphone.
  • The receiver shall operate on 2.3 MHz or 2.8 MHz frequency.
  • The receiver shall have an individual rotary-type volume control on each individual earphone and a on/off selection switch on the right earphone.
  • The receiver shall have a slide-button frequency selector to choose between 2.3 MHz or 2.8 MHz operation.
  • The receiver shall provide 118 dB SSPL90 output, +/- 1 dB, and a signal-to-noise ratio of 60 dB.
  • The receiver shall operate up to 80 hours when using AAA alkaline non-rechargeable batteries.
  • The receiver shall be encased in a black, plastic case.
  • The receiver shall operate up to 3,500 ft2 (325 m2) when using a single WIR TX9 Emitter.
  • The receiver shall have CE, RoHS, and WEEE approval and be covered by a two-year parts and labor warranty, not including batteries or accessories.*
  • The receiver shall be the Williams Sound model WIR RX15-2.

WIR RX15-2

Receiver Style:


Earpad Size:

2.5" (6.5 cm) diameter, adjustable headband


5.5 oz (155g) without batteries

Color and Material:

Black, plastic

Operating Range:

Up to 3,500 ft2 (325 m2) when using a single WIR TX9 Emitter

Battery Type:

AAA Alkaline batteries (BAT 010)

Battery Life:

Alkaline: 80 hours

Battery Drain:

12 mA, nominal


ON/OFF switch

(2) Thumbwheel volume control knob, left and right

(1) Frequency slide-button selector, 2.3 MHz or 2.8 MHz Monitor button = mutes audio


LED - Power: RED = 2.3 MHz; GREEN = 2.8 MHz

Frequency Response:

30 Hz – 20 kHz

Signal-to-Noise Ratio:

60 dB (IEC weighted)

Magnetic Field Strength:

1.9 A/M per CFR 68.316)


FM wideband modulation

Acoustic Output:

118 dB MAX SSPL90, +/- 1 dB with 6 cc coupler




2-year warranty (excludes physical damage)*

WIR RX22-4N Architectural and Engineering Specifications

  • The receiver shall be a body-pack type with IR detector lens behind face of the unit.
  • The unit shall have a lanyard for hands-free operation.
  • The receiver shall have a rotary-type volume control.
  • The receiver shall operate for 60 hours with two AA alkaline batteries and for 30 hours per charge with NiMH AA batteries.
  • The receiver shall be charged without battery removal via charger contacts in the case. A drop-in charger accessory shall recharge the batteries in 16 hours when used with CHG 3512 charger.
  • The receiver shall be housed in an impact resistant plastic case with a hinged battery door that does not separate from the receiver.
  • The receiver shall receive 2.3 MHz, 2.8 MHz, 3.3 MHz or 3.8 MHz modulated IR signals with 50 µS de-emphasis. The receiver shall have a 3.5 mm stereo phone jack and accommodate low-impedance mono or stereo earphones and headphones.
  • The receiver shall accommodate neckloop telecoil couplers.
  • The receiver shall provide 125 dB SSPL90 output with HED 021 headphone and 110 dB SSPL90 with EAR 013 earbud-type earphone.
  • The system electrical frequency response shall be 25 Hz to 16 kHz, +1, -3 dB and the S/N ratio shall be 60 dB.
  • The receiver shall have CE, FCC RoHS and WEEE approval. The receiver shall be covered by a five-year parts and labor warranty, excluding earphones, headphones, batteries and chargers.
  • The receiver shall be the Williams Sound model WIR RX22-4.


Receiver Style:

Body-Pack, dual-lens detector, lanyard


4.1" L x 2.85" W x 1.2" H (104.1 mm x 72.4 mm x 30.4 mm)


4.5 oz (127 g) with batteries

Color and Material:



3 ft (0.91 m), allows receiver to be worn around the neck

Operating Temperature:

-10° C to +50° C

Battery Type:

2 x AA, alkaline (BAT 001-2) or NiMH (BAT 026-2)

Battery Life:

Alkaline: 60 hours, NiMH: 30 hours/charge

Battery Drain:

25 mA, nominal

Charging Contacts:

For use only with CHG 3512

Carrier Frequency:

Channel 1: 2.3 MHz, Channel 2: 2.8 MHz

Channel 3: 3.3 MHz, Channel 4: 3.8 MHz


50 uS

FM Deviation:

±50 kHz

Signal-to-Noise Ratio:

60 dB min.


Receiver squelches (mutes) at 40 dB S/N ratio

Frequency Response:

25 Hz to 16 KHz, +1 dB, -3 dB, electrical response

Total Harmonic Distortion:

Less than 1%, electrical response


ON/OFF/VOLUME: combination thumbwheel knob

Channel Selector: four-position rotary switch


Red LED “ON" indicator, flashes to indicate Low battery

Audio Output Jacks:

3.5 mm stereo mini phone jack Accepts 3.5 mm mono or stereo phone plug

Audio Output Power:

15 mW max at 32 Ω

Acoustic Output:

125 dB SSPL90 with HED 021; 110 dB SSPL90 w/ EAR 013


Better than 1 nW/cm2 for 40 dB signal-to-noise ratio




5 years on receiver, 90 days on accessories

Compatible Headphones/Earphones:

Mono or stereo, 8-32 ohms, 3.5 mm mini phone plug, HED 021, HED 026, EAR 013, EAR 014, EAR 022, NKL 001

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 91V WHT - WHITE transmitter

Accessories for SoundPlus® Two-channel Infrared System [WIR SYS 91V]

BAT 001-2 Two AA alkaline batteries

BAT 026-2 Two AA NiMH rechargeable batteries

CHG 1012 Digi-Wave charger, 12-bay

EAR 008 Over-ear, hook earphone

EAR 013 Single mono earbud

EAR 013 T Single Mini Earphone w/ Eartip

EAR 014 Dual Mini Earbuds

EAR 014 T Dual mini earbud w/ Eartips

EAR 022 Surround Earphone

EAR 041 Single, in-ear, isolation earphone

EAR 042 Dual, in-ear, isolation earphones

HED 021 Folding headphones

HED 024 Stereo Headphones

HED 026 Rear-wear, mono headphones

HED 027 Heavy-duty, folding, mono headphones

HED 040 Hearing-protector, dual ear muff headphones

NKL 001 Neckloop 18" (mono plug)

SS-6 Floor stand kit

TFP 010 Power supply for WIR TX9, WIR TX90


Download/View Name Type Language
WIR SYS 91v Sell sheet Sell Sheets English
Infrared Brochure - Low Res Brochures English
WIR SYS 91v Specifications Specifications English
SoundPlus™ 2-channel Infrared Listening Systems Manuals English
Infrared Brochure - High Res Brochures English


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