Williams Sound FM 557 Pro D Plus Dual FM & Wi-Fi Listening System, 24x Earphones
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Williams Sound FM 557 Pro D Plus Large Area Dual FM & Wi-Fi Assistive Listening System, Includes FM T55 D Transmitter, 24x PPA R37N Receivers & 24x EAR 022 Surround Earphones

SKU: WSFM55724PD MFR: FM 557-24 PRO D
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Key Features

  • Crystal-clear audio: FM system ensures everyone hears, improving focus and engagement.
  • Assistive listening system offers superior sound quality for lectures, tours, and more.
  • Dual FM & Wi-Fi system offers flexible connectivity, fitting various venue setups seamlessly.
  • Enhance accessibility with our assistive listening devices, ensuring ADA compliance effortlessly.
  • Easy to use: Receivers and transmitter pair quickly, offering immediate audio assistance.
  • Long-lasting battery life: Enjoy hours of uninterrupted listening with our efficient receivers.
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Williams Sound FM 557 Specifications

FM T55 D Transmitter: General

FM T55 D Transmitter: General

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  • Color

    Black/Silver with silver legends on the front, white legends on the back

  • 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 062); Input: 100-240 VAC, 50/60 Hz. IEC Line Cord; Output: 24 VDC, 750 mA, 18W. 2.5mm ID center positive barrel connector

  • Power ON Indicator

    Push On/Push Off latching power button, backlit green indicates power ON, backlight off indicates power OFF, fading from bright to dark indicates Sleep Mode

  • Temperature Range

    Operating: +32 to +104 Degree F (0 Degree C to 40 Degree C)
    Storage: -4 to +158 Degree F (-20 to 70 Degree C)

  • User Interface

    3.12" High Resolution OLED display with selections via buttons. Hosted Web page. Remote control and monitoring

  • Dante

    Yes

  • Ethernet

    RJ-45 on back of unit supports CAT 5e cable lengths up to 328 feet (100 meters); 10/100 Base-T IEEE 802.3 compliant, unique MAC address

  • Approvals

    FCC, RoHS3, WEEE, Industry Canada

FM T55 D Transmitter: RF

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  • Operating Frequencies

    72.1-75.9 MHz , 17 wideband channels (selectable)

  • Frequency Accuracy

    +/- 2 ppm stability, 0-50 Degree C

  • Deviation

    +/- 75 kHz maximum

  • Pre-Emphasis

    75 microsec

  • RF Field Strength

    Does not exceed 80 mV/m at 3 m

  • 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

  • RF Outputs

    10-32 stud connector in center of unit (pcb mounted)
    F-connector on rear chassis

  • RF Transmit Indicator

    1 Green LED On Air Indicator

  • RF Power

    Full, Medium, Low or OFF indicated by menu icon.

  • RF Time Out (sleep mode)

    30 min. duration, 4 hr. duration, or Always On selected via menu. Starts when audio is below -18 dB level with no button pressed for selected duration

FM T55 D Transmitter: Audio

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  • Audio Processor Functions

    DSP based
    Compression: 1:1, 1.5:1 or 2:1
    High-pass and Low-pass Filter Frequency control

  • Frequency Response

    31-16000 Hz, +/-3 dB (re: 1 kHz, +/-3 dB) ("Music" Audio Preset)

  • Signal-to-Noise Ratio

    67 dB (typical) Transmitted RF

  • Total Harmonic Distortion

    Less than 0.25% @ 1 kHz (RF output)

  • Common Mode Rejection

    Greater than 57 dB @ 1 kHz, Mic or Line

  • Audio Inputs

    Combination 3-pin XLR, 1/4" (TRS) jack for balanced or unbalanced line level, or balanced or unbalanced microphone with selectable phantom power

  • Audio Input Gain Adjust

    In menu, adjustable to 0 to -50 dB, in 1dB 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

  • Audio 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

  • Headphone Output

    1/4" TRS stereo jack, mono signal, 14.85 mW at +9dB, maximum in 33 O (level adjustable in menu 0 to -40 dB in 2 dB steps)

  • Line Output

    RCA jack (black), -10 dBV (.32 VRMS)
    Output impedance 100 Ohms at +9dB

FM T55 D Transmitter: Input Levels

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  • Microphone (at Audio Input Gain = 0dB)

    Nominal (1st Amber LED): -55 dBV (1.7 mV RMS)
    Overload Warning (Displayed on Screen): -15 dBV (180 mV RMS)
    Absolute Max. Rating: +20 dBV (10.0 V RMS)

  • Line (at Audio Input Gain = 0dB)

    Nominal (1st Amber LED): -25 dBV (55 mV RMS)
    Overload Warning (Displayed on Screen): +16 dBV (6.3 V RMS)
    Absolute Max. Rating: +20 dBV (10.0 V RMS)

FM T55 D Transmitter: Physical

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  • Dimensions (W x D x H)

    8.45 x 8.25 x 1.72" (21.5 x 21 x 4.4cm)

  • Weight

    Transmitter: 3.2 lb (1.45kg)

PPA R37N Receivers

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  • Color

    Black

  • Battery Type

    2x AA Alkaline or 2 x AA NiMH

  • Battery Life

    Two (2x) AA non-rechargeable alkaline batteries (BAT 001), approx. 50 hrs
    (2) AA rechargeable NiMH batteries (BAT 026), 1500 mAh, approx. 32 hrs

  • Current Consumption

    52mA nominal

  • Temperature Range

    - 0 to 50C

  • Channels

    17, accessed via seek button in battery compartment

  • Operating Frequencies

    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, 75.9 MHz

  • Intermediate Freq.

    75 kHz

  • FM Deviation

    75 kHz

  • De-Emphasis

    75 microS

  • LED Indicator

    Power: Green
    Low Battery: Flashes Green

  • AFC Range

    +/- 120 kHz

  • Sensitivity

    2 microV at 12 dB Sinad with squelch defeated

  • Input Overload

    100 mV

  • Frequency Response

    200 - 15 kHz

  • Modulation

    FM, +/- 75 kHz peak deviation

  • Signal-to-Noise Ratio

    65 dB min @ 100 uV

  • Receive Antenna

    Integral with earphone/headphone cord

  • Audio Output

    35 mW max, peak into 16 ohms

  • Output Connector

    3.5mm stereo/mono phone jack

  • Earphone

    Earbud-type with foam cushion, 3.5 mm plug, 32 O

  • Auto Shut-off

    Enters sleep mode after approx 6 mins of no RF signal

  • Approvals

    FCC, Industry Canada, RoHS, WEEE

  • Dimensions

    4.1 x 2.85 x 1.38" (104 x 72 x 35mm)

  • Weight

    With batteries: 4.6 oz (130g)
    Without batteries: 2.6 oz (73g)

EAR 022 Surround Earphones

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  • Style

    Around-ear speaker

  • Plug

    3.5mm mono

  • Cord

    39" (99.06cm)

  • Driver Size

    0.9" (23mm)

  • Nominal Impedance

    32 Ohm

  • Freq. Response

    20 - 20kHz

  • Max Power Input

    30 mW

  • Sensitivity

    118 dB at 1kHz

  • Weight

    0.52 oz (15g)

NKL 001 Neckloop

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  • Color

    Black

  • Connector

    3.5mm mono plug

  • Impedance

    8-16 Ohms

  • Input Power

    500 mW max

  • Magnetic Field Strength

    25 mW input at 1000 Hz produces 1.7 A/m 6" above the
    center of loop
    85microW input produces 0.1 A/m (IEC Standard)

  • Approvals

    RoHS, WEEE

  • Length

    18.5" (47cm) cord

  • Weight

    1.5 oz (42.5g)

CHG 3512 12-Bay Charger

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  • Color

    Black ABS

  • Power Supply Input

    90 - 240 VAC input

  • Power Supply

    TFP 037 Switching AC adapter, 5 VDC - 4A output

  • Charging Rate

    16 Hour Charge: 140 mA
    Pulse/Maintain: 140 mA

  • Charging Time

    16 hours nominal

  • Unit Capacity

    12 Units

  • Indicators

    Individual Charging Indicators: Red LEDs.
    LEDs blink when batteries are charged

  • Approvals

    CE, WEEE, RoHS

  • Dimensions (L x W x H)

    9.5 x 7.4 x 1.7" (24.1 x 18.8 x 4.3cm)

  • Weight

    1.2 lb (0.54 kg), excluding power supply

ANT 005 Antenna

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  • Use with

    PPA T45,PPA T45NET, PPA T27 Transmitters

  • Connector type

    F-connector

  • Cable type

    RG 59 coax

  • Nominal Impedance

    75 Ohm

  • Active Antenna Length

    80" (203cm)

  • Cable Length

    22' (6.7m)

IDP 008 ADA Wall Plaque

Jump to...

  • Dimensions (L x W x H)

    10.375 x 6.25 x 0.125" (26.3 x 15.9 x 0.31cm)

About Williams Sound FM 557

Are you in search of an advanced, high-quality, and comprehensive assistive listening system The FM 557 Pro D Plus Large Area Dual FM & Wi-Fi Assistive Listening System is a robust solution designed to cater to your needs. This innovative system integrates professional WaveCAST Wi-Fi audio server technology into a Williams Sound FM assistive listening system, offering exceptional audio quality built on a professional digital audio (DSP) platform.

The FM 557 Pro D Plus system includes an FM T55 D transmitter, 24 PPA R37N receivers, and 24 EAR 022 surround earphones. The FM T55 D transmitter supports both iOS and Android WaveCAST Apps, in addition to all current and legacy Williams Sound FM receivers operating on the 72-76 MHz bandwidth. This flexibility allows end users to listen with either an FM receiver or their own smartphone via the WaveCAST Listening App, providing a more discreet assistive listening experience.

The PPA R37N receivers are flexible and simple to use, featuring seek-button channel selection with access to 17 pre-set wideband frequencies between 72-76 MHz. They are compatible with a variety of Williams Sound transmitters and are digitally synthesized for enhanced audio clarity and stability.

The EAR 022 surround earphones provide excellent sound quality and can be used with all Williams Sound receivers and Pocketalkers. The system also includes a NKL 001 Neckloop, designed to magnetically couple the audio output from a Williams Sound unit into a hearing aid equipped with a T-Coil.

The package also comes with a CHG 3512 12-Bay Charger, an ANT 005 Remote Coaxial Antenna, an IDP 008 ADA Wall Plaque, and an RPK 005 Rack Panel Kit.

The FM 557 Pro D Plus Large Area Dual FM & Wi-Fi Assistive Listening System is an ideal choice for large spaces like auditoriums, lecture halls, and other public spaces. Its all-in-one design and Wi-Fi compatibility make it a convenient and cost-effective solution for organizations that need to provide assistive listening in various settings.

Williams Sound FM 557 Features

  • FM T55 Transmitter System Features
  • Professional audio inputs: 1/4"/XLR, phantom power, line level output jack
  • Audio presets: hearing assistance, music, voice and custom
  • 16-bit DAC provides 48Khz sample rate
  • 10 segment LED bar graph
  • FM T55 Transmitter Wi-Fi Features
  • Single-channel audio streaming over Wi-Fi
  • True professional audio interface
  • Supports 45 users in unicast mode or 1500+ users in multicast mode
  • Works with free WaveCAST iOS or Android apps
  • FM T55 Transmitter FM Features
  • Up to 1000' operating range
  • Adjustable RF power output
  • Professional DSP audio platform
  • Works with existing Williams Sound FM receivers
  • PPA R37N Receiver Features
  • Seek-button access to all 17 wideband frequencies in the 72-76 MHz bandwidth
  • Channel-lock capability
  • Battery-saving sleep mode
  • Low-battery indicator
  • Field tunable
  • EAR 022 Surround Earphone Features
  • Hangs on outside of the ear
  • Excellent sound quality
  • 3.5mm mono plug
  • 1m cord
  • Monoaural
  • 32 ohm
  • Recommended for FM receivers and select IR receivers
  • Designed for individuals with mild and low gain hearing loss
  • NKL 001 Neckloop Features
  • Integrated safety breakaway device
  • 18" Cord
  • Adult size
  • 3.5mm plug
  • Monoaural
  • 8-16 ohm
  • Recommended for PockeTalkers, FM receivers and select IR receivers
  • For individuals with moderate to severe hearing loss

Warranty Information

This product has a limited warranty of 24 months.

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Product Documents

User Manual

Key Features

  • Crystal-clear audio: FM system ensures everyone hears, improving focus and engagement.
  • Assistive listening system offers superior sound quality for lectures, tours, and more.
  • Dual FM & Wi-Fi system offers flexible connectivity, fitting various venue setups seamlessly.
  • Enhance accessibility with our assistive listening devices, ensuring ADA compliance effortlessly.
  • Easy to use: Receivers and transmitter pair quickly, offering immediate audio assistance.
  • Long-lasting battery life: Enjoy hours of uninterrupted listening with our efficient receivers.

What's in the box:

  • FM T55 D Transmitter
  • 24x PPA R37N Receiver
  • 24x CLP 023 Belt Clip
  • 24x EAR 022 Surround Earphones
  • 6x NKL 001 Neckloops
  • 2x CHG 3512 12-Bay Charger
  • 2x Power Supply
  • 24x (Pairs) BAT 026-2 AA NiMH Rechargeable Batteries
  • ANT 005 Remote Coaxial Antenna
  • IDP 008 ADA Wall Plaque
  • RPK 005 Rack Panel Kit
  • Williams Sound 2 Year Limited Warranty (90 Day Limited Warranty on Accessories & Lifetime Limited Warranty on Receiver & 1 Year Limited Warranty on Neckloop/Charger)