Whether you're producing, mixing or mastering, it's absolutely vital that you're able to hear what you're doing. By placing a monitor controller between your audio interface and your studio monitors, you can set yourself up with extra options, like a talkback microphone, a mono switch or the option to switch between two pairs of speakers.
What About My USB Audio Interface?
While you could simply connect your studio monitors and headphones directly to your audio interface - a set-up that works fine for a lot of folks - if you're looking for extra functions to help you create better mix-downs, you'll simply need a monitor controller. The same goes for the option to listen to music without having to switch on your computer.
A Studio Speaker Volume Control
The simplest monitor controllers are essentially a large volume knob that can come in handy if your audio interface sits in a rack on the other side of the room. More advanced monitor controllers offer additional features, like multiple outputs for connecting various sets of monitors; multiple inputs so your customers can listen to reference tracks; a talkback function for clean communication with the artist; or mono mode and phase invert for exposing imperfections in your mixes.
Passive and Active Monitor Controllers
While every good monitor controller won't colour or change the sound, in practice, every electronic device that you route an audio signal through will lightly affect the sound, and that includes active monitor controllers. Luckily, passive monitor controllers are a thing, or more specifically, devices that don't require any power supply and therefore don't affect the sound at all. On the downside, passive controllers typically lack extra functions since there's no current to power any, and a phenomenon called 'stereo drift' may cause your stereo image to shift ever so slightly.
Monitor Controllers for Mastering
Unfortunately, monitor controllers aimed at mastering don't exist. As such, mastering studios opt for uncompromising high-end monitor controllers, usually in the form of a 19" rack system in combination with a remote control.
Monitor Controller Software Plug-Ins
While a plug-in won't grant you any extra audio outputs, software-based monitor controllers do offer functions like mono and phase invert for your master bus. Virtually every DAW comes with a basic plug-in built-in, and Steinberg's Cubase Pro even has a fully configurable Monitor Control section.
5.1 Surround Sound Monitor Controllers
Audio interface monitor outputs almost always come in stereo pairs. If you're mixing surround sound, then a solid surround monitor controller is basically indispensable for quick-and-easy volume adjustments as well as the option to toggle a subwoofer and isolate individual speakers.
