I’m a fanboy of Grace Design's gear, so when they announced the m701 interface at the NAMM Show in January, I immediately got in touch with Michael and Eben Grace to ask if I might be able to review it when it became available. Now that I’ve had a beta unit here in my studio for a few months, I can confidently say that these are the converters of my dreams, and the hardware ecosystem they have created will make this a very enticing product for many studio configurations and installations.
Now that I’ve given away the conclusion in my opening paragraph, how about some details? The m701 is based around a 2 rack space frame with a built-in dual redundant power supply. The digital I/O of the base unit includes eight channels of AES/EBU, eight channels of ADAT, and stereo S/PDIF. It will work at any 1x, 2x, or 4x sample rate between 44.1 kHz and 192 kHz. The front panel has a large 800 x 480 pixel color LCD display for metering and configuration controlled via a large encoder dial and navigation buttons. After turning the m701 on for the first time, I was able to dive through the pages and settings without any documentation. That may seem impressive, but what’s even better is to connect your computer to the m701 via the Ethernet port on its back panel and use what they are calling GraceNet to access the brains of the unit from any web browser; this provides for real-time programming of the routing and metering, and offers the ability to save/load different workflow configurations from your computer. It’s brilliant and ironclad.
As an interface, you’re going to need ways to get audio in and out of the m701, right? The beauty of this system is in its modularity. There are eight card slots that can be any combination of 8-channel DAC or ADC modules utilizing the latest design of Grace’s converters. There’s also a new 4-channel mic pre card. Any combination of these modules can be installed, or swapped out later if your needs change. These cards all incorporate DB-25 connectors, making for quick and easy integration into an existing patchbay or for cabling directly to other hardware. There’s another panel for additional expansion: A 24-channel AES I/O board (also on DB-25). Other modules are planned for the future. Finally, there are the two interface slots reserved for computer connectivity. As of this writing, DigiLink (for connecting to an Avid HDX system), Dante, and RAVENNA/AES67. Future expansion plans include a USB card with 32 channels of driverless, class-compliant I/O – two of these interface cards will be able to run up to 64 channels of I/O simultaneously.
I have been using the m701 in my studio connected via either DigiLink or Dante. For my Pro Tools setup, I used the primary port on the DigiLink module in the m701 to connect to an HDX card running in Avid’s Pro Tools | HDX Thunderbolt 3 Chassis. The m701 then appears as two 16-channel interfaces in Pro Tools; the configuration was instant and seamless. To connect via Dante, I used both the NTP Technology DAD Core 256 Thunderbolt 3 interface, as well as the brand new Focusrite RedNet TNX [Tape Op #169] interface. These are both effectively a Dante PCIe card in an external enclosure with Thunderbolt 3 connectivity to the computer. If you are familiar with Dante networking and configuration, the setup is a no-brainer. I was also able to route via Dante to my Grace Designs m908 [Tape Op #152] for monitoring, thus keeping the signal digital as long as possible.
The ADC and DAC cards are likely going to be the most commonly used I/O modules for the m701 to get signals in and out of a computer in the studio. The operating level of these converters can be toggled between +18 dBu and +24 dBu on a per-channel basis. The line level gain on both AD and DA converters is also adjustable per channel, +/-20 dB in 0.1 dB steps, should one need to calibrate for compatibility with finicky outboard. The dynamic range of the converters is greater than 120 dB. If you want to get even deeper with the tweaking, the ADC cards can be set to any one of four oversampling filter types, and the DAC to those same four, plus two additional ones. Depending on the headroom you need, as well as the types of frequencies most prevalent in what you are tracking/monitoring, these options can help reduce pre-ringing and overshoot in the conversion process.
Given the specs on paper, I had high expectations for the m701's sound, so the first thing I played through it after patching it in was an Atmos mix I was working on. The sound of my jaw hitting the floor is still reverberating in my studio. My previous converters were also excellent, but the Grace really blew me away. The phantom center feels more solid and stable, the lowest frequencies feel like they never stop going deeper, and the highs are like silk. Honestly, the best thing I can say about them is that I don’t feel like I’m hearing any conversion happen. Whatever sound or music is passing through the m701 sounds like the source and nothing else. On the A/D side, I’ve been tracking a ton of drums, electric guitar, vocals, string sections, pedal harp, and more through the Grace cards. Mics have gone through Neve, Squarewave Industries, or Locomotive Audio preamps, and every source always plays back sounding exactly as I expected. Massive low end when that’s what was mic’d up, and gorgeous, never-strident highs. These are converters without character, but that’s actually their character – ultimate transparency. I choose mics, preamps, and compressors for the tone they can impart on a source; I never want my converters to add another layer of color to that. The m701 is the ideal translator of the creative choices I have made.
Additionally, I have used the Grace mic preamp cards in the m701; they are as pristine as you would expect from this company. Each card has four preamps, and if you install two cards in adjacent slots, they can be connected via a jumper cable that allows 8 channels of inputs on one of the preamp card’s DB-25 to pass the second four channels to the second card – slick! The preamps have up to 69 dB of gain (75 dB gain range total), phantom power, polarity switches, and a ribbon mode that can be engaged on each channel to protect ribbon mics from phantom power and increase input impedance. Preamps can also be grouped so that changing the gain on one unit will make them all move relatively.
Grace has added a 32x8 cue mixer to the m701, which allows you to create up to eight individual mixes from the GraceNet web controller page or the front panel, and route inputs directly to outputs. This lets you create latency-free headphone mixes for talent (they can also control these mixes themselves from a phone or tablet!) and adjust level, pan, and mute, as well as create up to eight Groups from any number of inputs. Outputs from the cues can be stereo or mono, and both inputs and outputs can be named specific to the cues.
Throughout my review period, I have updated the m701 a few times with new firmware, and even replaced a processor board as the unit evolved. Each revision brought more functionality and stability to what is effectively another computer running amazing converters. I’m now using the first public release version of the OS, and that, too, kicked everything up another notch. I have used the m701 with Pro Tools Ultimate 2024, Apple Logic Pro 11, Ableton Live 12 [Tape Op #160], and Steinberg Cubase 12. All applications run perfectly with it.
These are not inexpensive converters, nor are they meant to be. The m701 is, in my mind, the new standard for what audio converters should sound like, and with that quality comes an appropriate price tag. Grace plans to offer a variety of pre-configured systems via their dealers and will offer the option to create custom configurations. For those considering an upgrade to their interface/converters and want the best, I can’t recommend the m701 highly enough!