Many home studios feature a single audio interface and a single pair of stereo monitors and the de facto standard for connecting the two is to simply run a pair of cables between these two devices and control the monitoring level from the audio interface. It can start getting complicated when you wish to expand beyond a single interface or pair of monitors though. When you want to expand or have more input sources then you might need to invest in a monitor controller. This article talks about some of the issues and pitfalls associated with using an external monitor controller.

What Is A Monitor Controller?

The simplest monitor controllers act to simply put a volume control between your audio interface outputs and your studio monitors, either passive or active devices that have minimal inputs around the hundred pound mark. Going up from there in terms of features, and therefore cost, you will find more inputs for sources, more outputs for monitors and headphone/musician outputs. High end models may support surround sound formats from 5:1 all the way to Dolby Atmos and perhaps even AoIP technologies such as Dante. A few stereo monitor controllers are expandable to support surround sound formats, such as the Crane Song Avocet, but for the most part this is not possible.

Format - Rack and Remote vs All in One vs Remote Only

There are various formats available for monitor controllers, the main two being an all in one where the volume control, input/output sourcing and connections are contained in a single device. Devices such as the Mackie Big Knob, SPL MTC2381, Audient Nero, Presonus Monitor Station fit this description. Other, usually higher end designs, feature a separate rack and remote, where the connections are usually located in the rack device with a wired or wireless remote control. One of the popular devices of this type for home studios would be the Presonus Central Station, but for the well heeled also checked out the Grace M905 (and its surround capable big brother the M908), Crane Song Avocet, Shadow Hills Oculus and Dangerous Music Monitor ST. I’d posit that a third type exists which is a ‘remote only’ that acts as an expander to an existing audio interface, allowing you to remote control a supported audio interface from the mix position. The Monitor Operating Module (MOM) from Digital Audio Denmark, which expands their own AX series and the Avid MTRX and MTRX II would fit this description. It would also describe the Focusrite R1, which is a Dante monitor controller with talkback and headphone amplifier. Compatible with the Red series of interfaces. Owners of some Universal Audio Apollo rack mount interfaces can use the smaller desktop devices as monitor controllers, with the caveat that they need to be daisy chained from the one another, which may affect placement. Another example of this would be the remote for the Kii Three monitors, although that only works with that pair of (quite expensive) monitors.

Price vs Performance

As with everything in Pro Audio there is no free lunch. What separates a similarly specced £300 monitor controller from one that costs £3000 is audio specification. Higher end devices tend to be more transparent and less coloured - a desirable quality in a monitor controller, as you might expect. This doesn’t mean you need to spend thousands but one unfortunate quality sometimes found in cheaper units is a shift to the stereo imagine as you lower the volume, which is certainly suboptimal.

External Source Mixing

For me the major stumbling block that many monitor controllers seem to miss is the ability to monitor more than one source at once. The SPL MTC2381 is one noticeable exception here - any of the monitor sources can be summed to any of the three monitor outputs. Some higher end devices such as the Grace M905 do not allow you to mix input sources, in order to preserve audio quality. I hate to trade off audio performance for convenience but in this case I’d always prefer to be able to sum a few sources at once with an audio interface. Mac System sounds, in particular, is something that can be difficult to monitor, especially if using Pro Tools HDX. The work around here can be sending two channels out of the Mac system output into your audio interface, but that seems like a waste of channels when you could just sum at the monitor controller.

Software Monitor Controllers

Considering the fact that really transparent hardware monitor controllers are relatively expensive and the less expensive ones tend to affect the sound to some extent, there is a third option - the software monitor controller. It’s always been possible to control monitoring level from software. Whether controlling a master fader in Pro Tools or something more dedicated for monitor control such as the Control Room panel in Cubase. But third party, DAW agnostic software monitor controllers exist and have become more and more capable in recent years. Examples include Sonnox ListenHub which offers the functionality you would expect but accessed from a tablet of phone as well as on your computer for an experience which feels like a separate device. Another worthy contender is Groundcontrol Sphere from Ginger Audio which offers Dolby Atmos monitoring.

What I Am Using

In the past I’ve owned the SPL MTC2381 as a monitor controller of choice. As an ‘all in one’ design it meant that it needed to be located close to my mixing position and as my studio grew that became less convenient. I then moved to a Grace M905 which in addition to having a much better specification than the MTC2381 it allowed me to have the main unit in my audio interface rack with the remote control in the mix position. The Grace suited me well for a couple of years but a move to the Avid MTRX revealed a few issues, namely you cannot sum input sources in it- you can only monitor a single stereo pair and there is no support for surround sound.

Currently I am using the Avid MTRX II as my monitor controller and it works brilliantly. Any output channel (including those over Dante) can be configured as a monitor source. I currently have three sets of monitors in my studio, two pairs in the mix position and one near the modular synth, so I do not need to twist out of position when using it. It allows me to sum any input source to the monitor section or to any of the HP mixes that I have configured, It also supports surround formats, including Dolby Atmos, The MTRX II has a significant purchase price but the monitor controller is incredibly flexible. I control the monitoring in a variety of ways, either using the DADman application, from Avid Control/Dock, or using the pair of DAD Monitor Operating Modules situated around the studio. I am also frequently using the MTRX II purely as a studio monitor controller when working natively in Logic, Studio One or Ableton Live, sending signals to and from my native interfaces over Dante.

Conclusion

Hopefully this article outlines some of the promises and pitfalls associated with using an external monitor controller. I maintain that the best thing to do is let your monitoring needs dictate the product you purchase, whether that be an external ‘all in one’, a ‘rack and remote’ or simply using the monitor controller capabilities built into your audio interface. Let us know what you are using in the comments and whether you see yourself upgrading in the short or long term.