Williams AV FM 558-12 PRO – FM+ Listening System, 12 Receivers

Product Overview

The Williams AV FM 558-12 PRO is an assistive listening system for mid-size venues, combining the FM+ dual FM and Wi-Fi transmitter with 12 PPA R38N receivers and a professional installation accessory kit. It is a practical specification for lecture halls, council chambers, courtrooms, and houses of worship that need ADA-compliant hearing assistance with managed receiver checkout plus open smartphone listening over the WaveCAST app. Everything needed for a standard commercial install — antenna, rack panel, chargers, neckloops, and ADA signage — ships in the package.

Product Description

The FM+ transmitter broadcasts on 17 selectable wideband FM channels between 72.1 and 75.9 MHz while simultaneously streaming the same audio to the facility Wi-Fi network. Installers land a balanced or unbalanced microphone or line-level feed on the rear XLR/1/4-inch TRS combo input — with selectable phantom power for condenser microphones — and dial in the signal using 1 dB gain steps and a 10-LED level meter. DSP processing with selectable compression ratios and high-pass/low-pass filters tailors the feed for hearing-impaired listeners, and the half-rack chassis mounts in a standard 19-inch rack using the included RPK 005 panel kit. A 3.12-inch OLED display, hosted web page, and third-party room control support handle setup and ongoing management.

Each of the 12 PPA R38N receivers features a 1-inch OLED display, menu-driven channel selection with channel lock, a detachable belt clip, and a 3.5 mm stereo output jack. Battery life reaches roughly 50 hours on AA alkalines or 32 hours on the NiMH rechargeables that charge in the included two-bay charger kits. EAR 022 surround earphones and NKL 001 neckloops are supplied so the venue can serve listeners with or without telecoil-equipped hearing aids, and the ANT 005 remote coaxial antenna pushes FM coverage out to 1,000 feet. The IDP 008 wall plaque announces assistive listening availability at the entrance, satisfying common ADA posting practice.

Venues running Dante audio networks should consider the FM 558-12 PRO D with Dante input. Larger rooms can step up to the 24-receiver FM 558-24 PRO.

Key Features

• Dual FM and Wi-Fi Transmission — A single half-rack transmitter serves the 12 included FM receivers and unlimited WaveCAST app listeners on the venue network.
• 12 OLED Body-Pack Receivers — PPA R38N receivers deliver menu-based tuning across 17 wideband channels with channel lock for controlled deployments.
• Turnkey PRO Accessory Kit — Antenna, rack panel kit, chargers with rechargeable batteries, earphones, neckloops, and ADA signage are included for a complete install.
• Telecoil Compatibility — Included NKL 001 neckloops couple audio magnetically to telecoil hearing aids and cochlear implants.
• DSP Audio Processing — Selectable compression and filter settings improve speech intelligibility for assistive listening and interpretation feeds.
• Simple Commissioning — A 10-LED level meter, 1 dB input gain steps, and selectable phantom power streamline alignment with the house audio system.
• Web-Based Remote Control — The hosted web page over RJ-45 Ethernet enables monitoring, configuration, and room control integration.
• Extended FM Range — The included ANT 005 remote coaxial antenna provides coverage up to 1,000 feet.

Typical Applications

• Government space
• House of worship
• Training room
• Auditorium
• Commercial meeting space
• Multi-purpose room
• Conference room

Technical Specifications

Frequently Asked Questions

What distinguishes the PRO package from the base FM 558-12?

The PRO adds the professional installation accessories — ANT 005 antenna, RPK 005 rack panel kit, chargers with rechargeable batteries, neckloops, and IDP 008 ADA plaque — to the transmitter and 12 receivers.

How do listeners without a receiver hear the audio?

The transmitter streams the same program over the venue's Wi-Fi network to the free WaveCAST app, with no cap on the number of smartphone listeners.

Does the system require professional installation?

Yes. The FCC requires this transmitter to be professionally installed and used with approved FCC 15.203 compliant antennas, such as the included ANT 005.

Will the receivers work with hearing aids?

Yes. The included NKL 001 neckloops plug into the receiver's 3.5 mm jack and couple inductively to any telecoil-equipped hearing aid or cochlear implant.

Can the system be expanded later?

Yes. Additional PPA R38N receivers can be added at any time, and FM listener count on the selected channel is unlimited.

What warranty is provided?

Williams AV covers the transmitter for 2 years parts and labor; receivers carry the Lifetime PLUS Limited Warranty, with 90 days on most accessories.