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Williams AV FM 557-24 PRO FM Plus Dual FM & WiFi Assistive Listening System with 24 Receivers


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Part of the FM+ Assistive Listening Systems lineup from Williams AV, the FM 557-24 PRO is an FM+ Large-area Dual FM and Wi-Fi® assistive listening system that includes (24) FM R37 receivers. Similar to the FM 557-24 system, it adds coaxial cable and rack-mount kit as well, enabling professional installation.

FM+ Systems from Williams AV

This groundbreaking tech provides an industry-first choice of employing traditional FM receivers or using personal electronic devices over Wi-Fi for hearing assistance. Along with this versatility comes exceptional audio quality, as FM+ is assembled on a professional digital audio (DSP) platform. This technology is designed to support those who want to use their own smartphones and headphones for a more discreet assistive listening experience. Simplicity and flexibility is also available for those who prefer a more traditional assistive listening system with a dedicated FM receiver and headset. Now, venues will no longer need to choose between providing FM or Wi-Fi assistive listening systems. FM+ supports the iOS and Android WaveCAST Apps as well as the Wi-Fi Receiver-- in addition to all of the current and legacy Williams AV FM receivers that operate on the 72-76 MHz bandwidth.


Assistive Listening • Interpretation • Audio Description • Presentation • Education/Training


  • (1) FM T55 transmitter
  • (24) PPA R37N receivers
  • (24) EAR 022 surround earphones
  • (6) NKL 001 neckloops
  • (2) CHG 3512 12-bay chargers
  • (24) BAT 026-2 AA NiMH rechargeable batteries
  • (1) ANT 005 remote coaxial antenna
  • (1) IDP 008 ADA wall plaque
  • (1) RPK 005 rack panel kit

System Features

  • Professional audio inputs: ¼"/XLR, phantom power, line level output jack.
  • Audio presets -- hearing assistance, music, voice and custom
  • 16-bit DAC provides 48 kHz sample rate
  • 10-segment LED bar graph


  • Note: specifications and further information can be found within the items located under the "Documentation" tab above.

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