Williams AV FM 558-12 – FM+ Dual FM/Wi-Fi System, 12 Receivers

Product Overview

The Williams AV FM 558-12 is a mid-size venue assistive listening system pairing the FM+ T55C dual FM and Wi-Fi transmitter with 12 PPA R38N receivers. It delivers ADA-compliant hearing assistance for lecture halls, courtrooms, training rooms, and worship spaces, broadcasting simultaneously to dedicated FM receivers and to smartphones running the WaveCAST app on the venue network. This base system package suits integrators who specify antennas, chargers, and mounting hardware separately or already have that infrastructure in the rack.

Product Description

The FM+ T55C transmits on 17 selectable wideband channels in the 72.1–75.9 MHz band, reaching up to 1,000 feet with a compatible remote antenna such as the Williams AV ANT 005. At the same time, it streams identical audio over the facility's Wi-Fi network, so total listener capacity is never limited by the hardware receiver count. Audio enters through a combination XLR/1/4-inch TRS jack that handles balanced or unbalanced microphone or line-level sources with selectable phantom power, and DSP processing offers selectable compression and high-pass/low-pass filtering for clear, intelligible speech. The half-rack chassis fits standard 19-inch racks with optional RPK 005 or RPK 006 mounting kits, and configuration runs through a 3.12-inch OLED front panel or the unit's hosted web page over Ethernet, including third-party room control integration.

The 12 included PPA R38N receivers are body-pack units with 1-inch OLED displays, menu-based channel selection, channel lock, and detachable belt clips. They run approximately 50 hours on two AA alkaline batteries or 32 hours on NiMH rechargeables, and bottom-mounted charging contacts make them compatible with CHG 3512 and CHG 3502 drop-in chargers if the venue adds charging stations. Receiver audio outputs through a 3.5 mm stereo jack that supports earphones, headphones, or neckloops for telecoil hearing aid users.

For a fully outfitted deployment with antenna, chargers, neckloops, rack kit, and ADA signage in the box, see the FM 558-12 PRO package, or browse all systems in the Williams AV collection.

Key Features

• FM and Wi-Fi from One Chassis — The FM+ T55C feeds the included FM receivers and unlimited WaveCAST app users simultaneously, covering every listener type in the room.
• 12 R38N OLED Receivers — Each receiver provides 17-channel menu tuning, channel lock, and a bright 1-inch OLED display for quick, error-free operation.
• DSP Audio Conditioning — Selectable compression ratios and filter controls keep speech intelligible for hearing-impaired audiences.
• Pro-Grade Analog Input — The XLR/TRS combo jack accepts mic or line sources, balanced or unbalanced, with selectable phantom power and 1 dB gain adjustment.
• Rack-Mount Half-Rack Design — One or two transmitters mount in a single 19-inch rack space with optional RPK 005/006 kits.
• Long Battery Runtime — Receivers run up to 50 hours on alkaline or 32 hours on NiMH batteries, with drop-in charger compatibility for fleet management.
• Network Remote Management — The hosted web page over RJ-45 Ethernet supports remote control, monitoring, and room control system integration.
• Scalable Listener Capacity — Unlimited Wi-Fi app listeners and expandable FM receiver counts let the system grow with the venue.

Typical Applications

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

Technical Specifications

Frequently Asked Questions

What else do I need to complete the installation?

An FCC 15.203 compliant antenna (such as the ANT 005), a rack mounting kit if rack installation is required, and chargers if you use rechargeable batteries. The FM 558-12 PRO package bundles all of these.

Does this system meet ADA requirements for assistive listening?

It provides the FM receivers and Wi-Fi listening that form the core of an ADA-compliant solution. Add neckloops for telecoil users and post availability signage; verify receiver counts against ADA seating-capacity tables.

Can the Wi-Fi stream and FM run at the same time?

Yes. The transmitter broadcasts both transports simultaneously from the same audio input, so hardware receiver users and app listeners hear the same program.

What network does the Wi-Fi streaming use?

The transmitter connects via Ethernet to the venue's existing Wi-Fi network; it does not generate its own wireless network.

Is professional installation mandatory?

Yes. The FCC requires professional installation and the use of approved compliant antennas with this transmitter.

How long is the warranty?

The transmitter is warrantied for 2 years parts and labor; R38N receivers carry a Lifetime PLUS Limited Warranty, with 90 days on most accessories.