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Sweeten Your Audio and Your Wallet

Our FM-55 FM audio processor with stereo generator is simple and affordable, yet powerfully modern – right down to its AES digital multiplex into the exciter. You’ll be amazed what its intelligent five-band AGC, or iAGC, can do. For FM stations requiring sound consistency across a variety of source material, this is it.

FM55 Front

Unique among processors, the FM-55 includes new intelligent five-band AGC technology — or iAGC — coupled to a five-band limiter and stereo generator. The combination provides automatic and superior real-time program density control for a consistent, spectrally-balanced sound regardless of density variations in incoming source material.

Other features of the FM-55 include our five-band stereo enhancement and program adaptive L-R control for multipath mitigation.

The FM-55 fully supports the WheatNet-IP Intelligent Network, and is equipped with two analog composite outputs, two SCA inputs, balanced analog Left/Right outputs and an AES digital output which may be switched to deliver either discrete Left/Right or baseband192 digital multiplex signal. Input audio may be delivered via analog, AES or WheatNet-IP.

The composite output signal is available as traditional analog via twin rear panel BNC connectors and simultaneously as Wheatstone’s baseband192 digital multiplex technology.

Smartly designed with a front panel OLED display, Guru GUI navigation and headphone jack on the front panel, the FM-55 has the incredible sound and build quality that the industry has come to expect of a Wheatstone audio processor.

The FM-55 represents an exceptional value for the LPFM broadcaster, and can be packaged with an Audioarts AIR-1 or AIR-4 console for on-air, production and processing at an affordable price.


FM55 Rear


Intelligent iAGC
An FM-55 exclusive, our newly developed adaptive iAGC – or intelligent AGC – which allows unobtrusive transitions between hyper-compressed recordings and those with more dynamic range. Our iAGC effectively manages the behavior of the multiband AGC as program content density changes, something a typical broadband AGC simply cannot do. By coupling the iAGC and mulitband AGC, we are able to produce a consistent, spectrally-balanced sound regardless of density variations in incoming source material.

Smart Stereo Enhancement
The FM-55’s Smart Stereo Enhancement provides a wide but extremely stable ‘on-air’ stereo image. “Wide”, “alive”, “exciting to listen to”, and “very natural sounding” are terms customers have used to describe how our stereo enhancement method sounds. Users have reported hearing artistically important nuances in music that were simply inaudible when the same material was processed by competing products.



  • Multiband adaptive iAGC

  • Newly developed Bass Management System

  • FM peak control via oversampled distortion masked clipper

  • Four-band equalizer: low/high shelf, two parametric

  • Exclusive stereo multipath controller technology for enhanced stereo reception
  • Wheatstone® baseband192 built in for composite digital link to transmitter

  • Variable high pass filter and voice phase rotator

  • Ethernet-based remote control via 100BaseT Ethernet and rear panel RJ-45

  • Four GPI triggers

  • Front panel headphone jack

  • AES3 digital input accepts 32kHz - 96kHz

  • AES3 digital output automatically synchronizes to AES3 digital input

  • Precision FM stereo MPX generator with multiplex mask filters

  • Specially tuned factory presets

  • Graphical User Interface, for easy setup and navigation

  • WheatNet-IP compatible

  • Front panel setup and configuration menu eliminates the need for a PC during installation

AirAura CarFromNickBass Management System
The FM-55’s Bass Management System is also new and circumvents bass-related distortion plaguing other broadcast audio processors. The result is increased depth, feel, and clarity of bass impact without affecting mid and high frequency program – in fact bass detail and the clarity of higher frequency audio are actually enhanced by the new algorithm.

MultipathExclusive Multipath Control

Exclusive to the Wheatstone line of audio processors is the Stereo Multipath Limiter. A single user control assigned to this algorithm sets it to mitigate market and terrain-specific multipath behavior, reducing the annoyances of multipath-triggered receiver-induced stereo blending. 

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WheatNet-IP Compatible
WheatNet-IP I/O compatibility makes it possible to control the FM-55 and stream its audio to and from anywhere in the IP audio network, making it 100% compatible with WheatNet-IP surfaces and controllers!

Wheatstone baseband192
Wheatstone® baseband192 digitizes the entire multiplex spectrum including RDS and SCAs up to 80kHz, providing a higher performance interface than using the classic analog composite method between processing and transmitter. A single AES/EBU cable between the processor and a current solid-state FM transmitter carries the digital baseband signal, bypassing the need for multiplexing in the exciter and eliminating the resulting signal overshoot with its associated loudness tradeoff. 


FM55 GUIAudio Processing Guru® Software 
Processing is as much art as science. If you’re more artist than scientist and have trouble keeping track of the dozens and sometimes hundreds of controls that modern processors offer, Audio Processing Guru® software will be the key to happiness. It condenses the functions of the various processor controls down to just a few, easy-to-understand sliders, enabling you to concentrate on what you hear, not what you see. It’s as if we sent a processing expert with each box! GUI Guru makes the tough, behind-the-scenes decisions based on the simple-to-use controls supplied for texture (Drive, Density, Loudness) and EQ (Low, Warmth, High).

WheatNet-IP Extends Wheatstone Processors’ Power

images/NEW_FOR_NAB_IMAGES/NAB_NEW_BLADES.jpgWith WheatNet-IP BLADE-3s, you get a virtual rack room in a 1-rack space box. They handle all the I/O (AES/EBU, SPDIF, AOIP, MADI, SDI and AES 67) and provide full routing capabilities. Each BLADE-3 gives you two 8x2 utility mixers, 12 universal GPI/O ports, 128 software logic ports, silence detection, built-in audio clip player, stereo multi-band audio processing, and much more, assignable anywhere on the network. With it you can create workflows that would require a ton of third-party gear.

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