Williams Sound Assistive Listening System FM457



The Williams Sound FM 457 is 4-receiver FM assistive listening system. The FM 457 features the cutting-edge PPA T45 transmitter, with multiple digital audio input options and an OLED display with easy-to-manage menu navigation. Features three powerful microprocessors and the same high-quality audio and RF performance you’ve come to expect from Williams Sound. With an operating range of up to 1000 feet, the FM 457 is ideal for large venues where superior coverage is essential. This complete turnkey solution includes four R37 receivers, each featuring seek-button channel selection with access to 17 pre-set wideband frequencies between 72-76 MHz. The system is expandable, accommodating any number of listeners. This system complies with 2010 ADA guidelines for hearing assistance and is covered by Lifetime PLUS Limited Warranty.

NOTE: Approved by the FCC for operation in U.S. markets. The system cannot be used in all countries. Check with your government radio regulations for 72-76 MHz operation.

Item# WMSFM457

UPC 609015892718


SKU: WMSFM457 Category: Tag:


  • PPA T45 Assistive Listening Transmitter
    Rack Mount Standard 19″ Rack, one EIA rack space high, 1/2 space wide
    1-2 units can be mounted in a single rack space with optional RPK 005 (single) or RPK 006 (double) rack mount kits
    Power Supply Desktop-style transformer (TFP 048)

    Input: 100-240 VAC, 50/60 Hz, IEC line cord

    Output: 24 VDC, 750 mA, 18 W, 2.5 mm ID center positive barrel connector

    Approvals: UL, CUL, Energy Star V, CSA listed

    Indicators Power Indicators: Push On/Push Off latching power button, backlit Green indicates Power ON, back-lit off indicates power OFFAudio Level Indicators: 10-LED array that reads -18 to 9 dB at 3 dB intervals. 7 Green, 2 Amber, and 1 red LED. Green LEDS indicate normal operating audio level peaks, Amber LEDS indicate close to overload peaks, Red LED indicates overload peaks
    Temperature Range Operating: 32 to 104°F (0 to 40°C)
    Storage: -4 to 158°F (-20 to 70°C)
    Menu Options Audio Presets (Music, Voice, Hearing Assist, Custom), Frequency/Channel selection, Frequency/Channel mode, Audio Input Source (Microphone, Line, Phantom, Digital AES/EB, Digital S/PDIF), High Pass Filter, Low Pass Filter, Compression, RF Output Power, Screen Saver Delay, Test Tone (400 Hz), Headphone Volume, Headphone Source
    Operating Frequencies 72.1 to 75.9 MHz, 17 wideband channels (selectable)
    Frequency Accuracy ±2 ppm stability, 32 to 122°F (0 to 50˚C)
    Deviation ±75 kHz maximum
    Pre-Emphasis 75 µsec
    • RF Field Strength: Does not exceed 80 mV/m at 9.8′ (3.0 m)
    • RF Timer: Menu selectable – 30 Min, 4 Hours, or Always On
      Time starts when no audio is present
    • RF Power: Menu selectable – High, Medium, Low, OFF
    • RF Outputs: (1x) #10-32 stud connector in center of unit (PCB mounted), (1x) F-connector on rear chassis
    • RF Transmit Indicator: 1 Green LED, indicates RF “ON”


    Antenna Type Compatible Antennas: ANT 005, ANT 021, ANT 024, or ANT 025
    Transmission Range Up to 1000′ (304 m) with ANT 005 coaxial antenna mounted on rear chassis connector
    Audio Processing Functions DSP, Compression: 1:1, 1.5:1 or 2:1, High Pass and Low Pass Filter Frequency control
    Frequency Response 31 Hz to 16 kHz, ±3 dB (“Music” audio preset)
    Signal-to-Noise Ratio ≥74 dB Transmitted RF
    Total Harmonic Distortion Less than 0.25% @ 1 kHz (RF output)
    Common Mode Rejection >57 dB @ 1 kHz, Mic or Line
    Audio Inputs 1x combination 3-pin XLR, 1/4″ TRS jack for mic or line level analog audio, balanced or unbalanced line level, or microphone with selectable phantom power
    1x XLR for digital audio, AES3/EBU, supported sample rates 44.1 and 48 kHz
    1x RCA for digital audio, S/PDIF, supported sample rates 44.1 and 48 kHz
    Gain Adjustment In menu, adjustable to 0 to -50 dB, in 1 dB steps
    Phantom Power 14.4 VDC applied through 2.2 kOhms resistors to analog combo jack: Pin 2 and Pin 3 on XLR jack, or tip and ring on 1/4″ TRS jack
    Input Level Microphone:
    -55 dBV (1.7 mV RMS), nominal (1st amber LED)
    -15 dBV (180 mV RMS), overload warning (displayed on screen)
    20 dBV (10.0 V RMS), absolute maximum ratingsLine:
    -25 dBV (55 mV RMS), nominal (1st amber LED)
    16 dBV (6.3 V RMS), overload warning (displayed on screen)
    20 dBV (10.0 V RMS), absolute maximum ratings
    Headphone Output 1/4″ TRS stereo jack, mono signal, 15.7 mW, maximum in 33 Ohms (level adjustable in menu 0 to -40 dB in 2 dB steps)
    Line Output RCA jack (black), -10 dBV (.32 V RMS), output impedance 100 Ohms
    Ethernet RJ-45 on back of unit (PPA T45NET only)
    Approvals FCC, RoHS2, WEEE, Industry Canada
    Dimensions 8.45 x 8.25 x 1.72″ (21.5 x 21 x 4.4 cm)
    Weight Transmitter: 3.0 lb (1.36 kg)
    Packaging Info
    Box Dimensions (LxWxH) 12.756 x 10.551 x 3.543″
  • PPA R37 N Select Channel FM Receiver (No Earphone/Batteries)
    Channels 17, Accessed via Seek Button in Battery Compartment
    Operating Frequency 72.1, 72.2, 72.3, 72.4, 72.5, 72.6, 72.7, 72.8, 72.9, 74.7, 75.3, 75.4, 75.5, 75.6, 75.7, 75.8, 75.9MHz
    75kHz Intermediate Frequency
    Deviation 75kHz
    De-Emphasis 75µS
    Range AFC Range: ±120kHz
    Sensitivity 2µV @ 12dB Sinad with Quelch Defeated
    Max Input Signal 100mV
    Frequency Response 200Hz – 15kHz
    Modulation FM, ±75kHz Peak Deviation
    Signal to Noise Ratio 65dB Min @ 100µV
    Output Level 35mW Max, Peak into 16 Ohms
    Connectors 3.5mm Stereo/Mono Headphone Jack
    Antenna Uses Earphone/Headphone Cord as Antenna
    Battery 2 x AA Alkaline or NiMH
    Up to 50 Hours Life with Alkaline, Up to 32 Hours with Rechargeable NiMH
    Enters Sleep Mode After 6 mins with no RF Signal
    Current Consumption 52mA, Nominal
    Indicators Green Power LED (Flashes for Low Battery)
    Temperature Range 32 to 122°F (0 to 50°C)
    Approvals FCC, Industry Canada, RoHS, WEEE
    Finish Black
    Dimensions (HxWxD) 4.1 x 2.85 x 1.38″ (104 x 72 x 35mm)
    Weight 4.6 oz (130g) (With Batteries)
    2.6 oz (73g) (Without Batteries)
    Packaging Info
    Box Dimensions (LxWxH) 4.0 x 3.0 x 1.0″
  • EAR 022 Surround Earphone
    Style Around-ear speaker
    Plug 1/8″ / 3.5 mm mono
    Driver Size 0.9″ / 23.0 mm
    Nominal Impedance 32 Ohms
    Frequency Response 20 Hz to 20 kHz
    Power Input 30 mW
    Sensitivity 118 dB @ 1 kHz
    Cord Length 39.0″ / 99.1 cm
    Weight 0.5 oz / 15.0 g
    Packaging Info
    Box Dimensions (LxWxH) 2.7 x 2.2 x 0.3″
  • NKL 001 Induction Neckloop for T-Switch Hearing Aids
    Magnetic Field Strength 25 mW input at 1000 Hz produces 1.7 A/m 6″ above the center of loop
    85μW input produces 0.1 A/m (IEC Standard)
    Input Power 500 mW max
    Impedance 8 to 16 Ohms
    Connector 1/8″ / 3.5 mm mono mini-plug
    Cable Length 18 / 457 mm
    Color Black
    Approvals RoHS, WEEE
    Weight 1.5 oz / 43 g
    Packaging Info
    Box Dimensions (LxWxH) 5.6 x 4.1 x 1.0″


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