Welcome to the third instalment of “The Art of FOH Monitor Mixing.” In “The Art of FOH Monitor Mixing, Part 2: Setting Up the Mix” we talked about ringing out the system and communicating with the band during sound check. In this article, I’ll share some processes for improving your monitor mix so the artist can hear more accurately and give a better performance. Veteran sound engineers could easily fill an entire book with helpful tips to improve clarity, reduce feedback and ultimately make the musicians happy, but here are five tips and tools every live sound engineer can apply to improve their monitor mixes.
A noise gate is a dynamics effect that cuts or attenuates a channel when the signal is below a variable threshold. You can use gates on the kick, snare and tom channels so the signal only comes through when the drum is struck and then closes to ensure that their sympathetic vibrations don’t muddy up the monitor mix—or even worse, slowly take off into a humming feedback. Set the attack time to be fast with a slow release time, and reduce the depth so that the signal is attenuated but the opening and closing of the gate can’t be audibly heard.
The dbx 1074 Quad Gate is a four-channel gate.
Two EQs, One Mic
Often you will find that a vocal EQ that sounds good in the FOH system will sound muddy in the monitor mix or vice versa. One method of working around this is “multing” the vocals. Use a microphone splitter or digital console patching to feed two separate channel inputs with the same vocal microphone. One of these channels will be for your front of house mix only, and one will be for the monitor mix only. You can EQ the monitor channel of the vocal to reduce feedback and use a different EQ on the main channel of the vocal to ensure it cuts through in the main mix. This process will take up an extra channel on the board for each input you want to “mult”, so keep this in mind when configuring the channel count for your board.
Reverbs and Delays
“Can I get some reverb in my monitor?” is a common question live sound engineers hear. Singers are known to be self-conscious about their voice. Reverb softens the edges of a vocal and can make a singer feel better about their voice, which can create a more inspired and passionate performance. Send the FX return channel to the monitor bus to give them the reverb they ask for. Be careful though—too much verb will obscure their ability to discern pitch and can cause more feedback problems.
High Pass Filters
If you’re having difficulty taming the low end of a mix, you can use a high pass filter (or HPF) to remove unwanted low frequencies from each instrument and microphone channel. This process is also common when mixing FOH, but becomes even more crucial when trying to minimize the danger of low frequency feedback from the monitors on stage. The general rule of thumb is to sweep the filter from low to high and dial back when you audibly hear the tone begin to suffer. With a few exceptions, 80Hz – 100Hz is a good place to start for vocals and most other instruments. For kick drum, tom and bass channels; search around 40Hz – 50Hz. Don’t be afraid to explore higher cut-offs, but keep in mind that this setting will affect your FOH mix as well.
Vocals are often the most dynamic element to work with in live sound. Gently compressing the lead vocal channel will help the vocal remain at a comfortable level in the monitor mix without jumping out of pocket and crossing the threshold of feedback. Set a low ratio (< 2:1), quick attack time and medium release time; then adjust the threshold until the gain reduction meter is reading between -3dB and -6dB. Use a soft knee if your compressor has the capability. Take note that if you compress too heavily, you will squash the vocal and increase the likelihood of feedback. For more approaches to compression and vocal processing, check out this HARMAN blog post about getting the right vocal-to-instrument balance.
These are just a few of the different processes you can use to stay in control of the monitor mix. In the world of live sound, the end result is what matters most. Not every method is necessary for every application. Try experimenting with processing and see the difference it can make to the musicians on stage.
First published in the HARMAN Insights Blog by Greg Dorris.