m908 RCU left detail


stereo / surround / immersive reference monitor controller

04/2024 – latest 2.x firmware release:

Room Tuning Enhancements

  • Speaker EQ setion now includes a familiar frequency/gain style graphical window area which allows quick ‘click and drag’ EQ curve editing. Specific frequency, gain and Q can still be manually entered.
  • High and Low Shelving filters now include slope controls
  • Bass Management LPF’s now include an offset trim amount
  • Channel Delay settings now operate with 1 sample resolution

Network connectivity

We have added a ‘Link-Local’ newtork connection, which provides simple direct acces to the m908 Web UI from any computer via an ethernet cable.

Please visit our support page to download the latest m908 firmware release.

Important Bulletin:

m908’s with serial numbers 908000400 and below (from 12/2022 and earlier) may begin experienceing internal SD card failure. Please read the bulletin posted on our support page, and contact our service department to have this issue reslved. 303-823-8100 x105 / email service@gracedesign.com

m908 RCU

The Finest Stereo to Immersive Monitoring

The m908 Monitor Controller is designed for speaker systems up to 24 channels, from stereo to Dolby Atmos™, SONY 360RA™ or any format in between. Built on our legacy of reference audio design, the m908’s audio performance delivers impeccable clarity and detail. Our latest generation AD / DA converters provide incredible dynamic range and resolution, while all new analog circuitry is designed to be effortlessly transparent and musical.

The All in One Solution

The m908 system consists of a mainframe audio control unit, remote control unit, and a power supply with dual-redundant universal input power modules. The remote control is based on our m905 stereo monitor controller, but scaled up to accommodate added features and playback channel count.

Full Featured

Standard features include a total of 68 digital input channels via AES3, TOSLINK, S/PDIF, ADAT Lightpipe, and USB2. Outputs include 16 balanced analog output channels and 24 digital output channels. Up to 16 channels of analog inputs are available with the addition of the optional 8 channel ADC modules, and an additional option module slot provides up to 32 additional digital I/O channels via Dante™, DigiLink™ and Ravenna / AES67 / st2110.

Powerful DSP

Up to 24 input channels can be received simultaneously and routed to the 24 channel processor, and sample rates of up to 192kHz / 24bit are supported. A powerful DSP section allows for 12 bands of parametric room correction EQ on every channel (or variable numbers of bands per channel totaling up to 85), comprehensive bass management features and individual channel delay.

Plug and Play Simplicity

The m908 is a fully self contained plug and play monitor controller, with a full complement of monitoring features including cue channels, built in talkback mic, mono, mute and dim controls, and an exhaustive list of functions relating to surround and immersive playback systems. It is designed to enable professionals and facilities to update their workflows for immersive audio playback with a minimum of effort and cost.

Luis del Toro

The m908 is the best Atmos monitoring system made. It’s easy to setup with an intuitive web interface, a fantastic remote control and it sounds luxuriously transparent. It makes my day easier. Thanks Grace Design!! – Luis del Toro /  luisdeltoro.com/


  • Standard digital inputs include: 24 channel AES3 digital, 16 channel ADAT Lightpipe, USB 24 channel inputs, AES3, S/PDIF, and TOSLINK stereo inputs
  • Analog inputs are optional: 8 channel ADC module for 8 or 16 channel analog inputs – these modules are sold separately
  • Standard outputs include: 24 channel AES3 digital out, 16 channel analog balanced out, 24 channels USB2 out
  • Optional Dante™, DigiLink™, Ravenna / AES67 / st2110 modules for an additional 32 channels of I/O
  • 4th generation s-Lock pll clocking system for vanishingly low jitter
  • High resolution volume control
  • Complete bass management capability
  • 12 bands of parametric room correction EQ on every channel / variable numbers of bands per channel, 288 bands
  • 64-bit fixed-point filters for room correction and bass management
  • Channel level and delay calibration
  • Comprehensive downmix control
  • Built in real time SPL meter
  • Powerful and intuitive remote control unit for access to all system controls and calibration
  • Dual redundant external power supply
  • Reference quality headphone amplifier with cross-feed
  • Flexible talkback system with built-in mic on remote control and mic input for external talkback mics
  • Up to 8 stereo CUE paths
  • 4 General Purpose Input and Output pins for interfacing to external systems

While the software configurability is very impressive, the quality of the hardware is crucial, and the m908 has the wonderfully well-engineered character we’ve come to expect from Grace Design. – Hugh Robjohns, Sound on Sound Magazine (full review here)

m908 rear panel view with RCU

Web UI for Control and Setup

The all-new embedded web control and setup platform allows you to control all monitoring features, and edit, load and store all system parameters. The interface works on any desktop or device browser that is connected to the same LAN as the m908.

Using this platform is as simple as entering the IP address of your m908 into a browser. The m908 will automatically load the control platform and work from there. There is nothing to download or install and it is completely agnostic to the desktop or device OS. This allows complete control and editing of all m908 system parameters from your screen without having to navigate the m908 RCU setup menus. This significantly increases the simplicity and efficiency of operating the m908!

m908 Web UI home screen

The main monitor control screen provides all the monitoring controls, laid out in a simple, graphical work environment. Any changes made by the web control software are instantly synchronized with the m908 RCU.

m908 Web UI monitoring setup

The system setup menus on the left provide easy navigation access to every m908 configuration setting, with simple sliders, menus, buttons and text fields for making system setup and calibration changes.

m908 Web UI EQ controls

Room correction EQ is as simple as entering values or clicking and dragging EQ points on the screen. Any individual EQ band can be copied and pasted or an entire channel of multiple EQs can be copied and pasted.

m908 Web UI solo / mute setup

Complex solo / mute speaker groupings can be made by simply selecting a specific solo / mute switch and adding or subtracting individual speakers to create the grouping.

m908 Web UI routing matrix

System I/O routing in the Web UI can be done in the matrix routing window, which allows you to quicky and easily assign any input channel to any speaker channel. This greatly streamlines any setup process.

m908 Web UI settings panel

The settings panel allows users to enter a browser tab name for the m908, select dark or light theme, activate confirmation dialogs, select list or tile view for the room EQ, and enable a lockout for the home screen controls.

Powerful Room Correction EQ Capability

Firmware v.2 and up provides a significant increase in the amount of total available EQ bands. Since the m908’s original release, one thing has become clear: Dolby ATMOS Room calibration can require very large amounts of room correction EQ. With this release, the m908 can now run 12 bands of EQ per channel on all 24 outputs, at any sample rate (288 bands available).

With the new control and setup software, EQ settings can be copy / pasted between individual speakers or speaker systems. Also, entire room EQ settings can now be imported and exported directly to the m908 imported via .csv files.

Make sure your m908 is up to date Please visit our support page here to download the most current m908 system firmware

m908 rearpanel connections

m908 remote control unit features

m908 Remote Control features
m908 at Real World Studio
The m908 installed at Real World Studio's Red Room
TEC award nomination
resolution award 2021
m908 TEC award

The Grace Design EON and STANDARD Warranties

We back up everything we make with either our unrivaled 20 year EON limited warranty, or the 5 year standard limited warranty. These represent the best coverage in the business and prove our commitment to the quality, serviceability and long term value of Grace Design products.

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