Williams AV FM 558-24 PRO D – Dante FM+ Assistive Listening System, 24 Receivers

Product Overview

The Williams AV FM 558-24 PRO D is a large-area assistive listening system that pairs a Dante-enabled FM+ T55C D transmitter with 24 PPA R38N receivers and a complete set of professional installation accessories. Built for ADA compliance in auditoriums, performing arts centers, and large houses of worship, it broadcasts the same program audio simultaneously over FM (72.1–75.9 MHz) and Wi-Fi, so attendees can listen on a dedicated FM receiver or their own smartphone via the WaveCAST app. The Dante input lets integrators pull audio directly from a networked audio system without analog conversion, making this the top-tier FM 558 package for modern AV-over-IP installations.

Product Description

At the heart of the system is the FM+ T55C D transmitter, a half-rack, 1RU device that transmits dual FM and Wi-Fi audio from a single chassis. The Dante network audio input accepts a channel straight from a Dante-enabled DSP, mixer, or audio processor over the facility's existing Ethernet infrastructure, while a combination XLR/1/4-inch TRS input with selectable phantom power covers analog microphone or line-level sources. DSP-based audio processing with selectable compression and high-pass/low-pass filtering keeps speech intelligible for hearing-impaired listeners. A 3.12-inch OLED display and a hosted web page provide local and remote configuration, and the transmitter integrates with third-party room control systems for managed operation.

The 24 included PPA R38N body-pack receivers each feature a 1-inch OLED screen, menu-based access to all 17 wideband channels, channel lock, and up to 50 hours of runtime on alkaline batteries or 32 hours on the included NiMH rechargeables. Two CHG 3512 12-bay drop-in chargers keep the entire receiver fleet charged and staged, and six NKL 001 neckloops serve listeners with telecoil-equipped hearing aids. The PRO accessory kit rounds out the deployment with 24 EAR 022 surround earphones, an ANT 005 remote coaxial antenna for up to 1,000 feet of FM coverage, an IDP 008 ADA wall plaque, and an RPK 005 rack panel kit for mounting the transmitter in a standard 19-inch equipment rack. Because the Wi-Fi stream supports an unlimited number of app listeners, capacity scales beyond the physical receiver count without additional hardware.

For venues that do not require Dante, see the FM 558-24 PRO analog package, or browse the full Williams AV assistive listening collection at Creation Networks.

Key Features

• Dante Network Audio Input — The FM+ T55C D transmitter accepts program audio directly from a Dante-enabled DSP or console, eliminating analog tie lines in networked AV systems.
• Dual FM and Wi-Fi Transmission — One transmitter broadcasts simultaneously over 72.1–75.9 MHz FM and the venue Wi-Fi network, serving both dedicated receivers and the WaveCAST smartphone app.
• 24 R38N OLED Receivers — Each body-pack receiver provides menu-driven access to 17 wideband channels with channel lock and a bright 1-inch OLED display for easy tuning.
• Unlimited Wi-Fi Listeners — The Wi-Fi audio stream supports any number of app-based listeners, so coverage scales past the 24 hardware receivers at no added cost.
• Complete PRO Installation Kit — The package includes an ANT 005 remote coaxial antenna, RPK 005 rack panel kit, and IDP 008 ADA wall plaque for a turnkey professional install.
• Fleet Charging Included — Two CHG 3512 12-bay drop-in chargers and 24 sets of NiMH rechargeable batteries keep all receivers ready between events.
• DSP Audio Processing — Selectable compression ratios and adjustable high-pass/low-pass filters optimize speech clarity for assistive listening applications.
• Remote Management — A hosted web interface and third-party room control compatibility allow IT and AV staff to monitor and adjust the transmitter over the network.
• Up to 1,000 ft FM Range — With the included ANT 005 antenna, FM coverage reaches up to 1,000 feet, suitable for the largest seating areas.

Typical Applications

• Auditorium
• House of worship
• Government space
• All-hands room
• Multi-purpose room
• Broadcast studio
• Commercial meeting space

Technical Specifications

Frequently Asked Questions

How does the Dante input integrate with an existing AV system?

The FM+ T55C D appears as a Dante receive device on the audio network. Using Dante Controller, you route a channel from any Dante-enabled DSP, console, or matrix directly to the transmitter — no analog wiring or D/A conversion required.

Does this system meet ADA assistive listening requirements?

Yes. The system provides FM receivers with neckloops for hearing aid telecoil coupling, and the included IDP 008 wall plaque signals assistive listening availability as required for ADA-compliant venues. Receiver counts should be verified against ADA seating-capacity tables for your venue.

Does the transmitter create its own Wi-Fi network?

No. The FM+ connects to the facility's existing Wi-Fi network via Ethernet; the wireless network must be in place before Wi-Fi audio streaming can be used. FM transmission works independently of the network.

Are there any installation requirements for the FM antenna?

Yes. The FCC requires this transmitter to be professionally installed with approved FCC 15.203 compliant antennas such as the included ANT 005. Williams AV's Antenna Selection Install Guide lists compliant options.

Can more than 24 people listen at once?

Yes. The Wi-Fi stream supports an unlimited number of listeners through the WaveCAST app, and additional PPA R38N receivers can be added to the FM side at any time.

What warranty applies to this system?

The transmitter carries a 2-year parts and labor warranty, and the R38N receivers are covered by Williams AV's Lifetime PLUS Limited Warranty (90 days on most accessories).