“Downward” or “subtractive” mixing describes the idea of “less is more” in monitoring mixing, and this technique applies very well to both wedges and earphones. So when we have an artist continually asking for more and more level from various sources in their ears, we should instead turn other elements down.
The artist still gets the balance adjustment they desire, but without an overall volume increase. And this is also a better approach when it comes to the science of proper gain structure in our mixing consoles and personal monitor mixing products (wired or wireless).
Mono Vs. Stereo Mixes
Mono in-ear mixes can be made to work. But those that use their systems in stereo eventually discover that there is a world of increased monitoring flexibility available to them. And humans aren’t designed for mono.
A mono IEM mix means that everything is heard “dead center.” That is, above the head in the virtual center of the sound image, or “phantom center.” A stereo mix allows the placement of sources to be panned across the stereo space in the listener’s head.
Here, various sources are intentionally panned in different places across the stereo image for the purpose of “un-mixing” them for monitoring. It is interesting to watch and see that musicians can (whether consciously or not) train themselves to “point” their listening to different directions in their head, depending on what sound they want to focus on at any moment.
It is important that the user’s own “me” signal stays prominent and in the center/top of their head, or “up the middle.” Say a musician has his acoustic guitar and the worship leader vocal both placed center in his head (good), and an electric guitar is panned to 10 o’clock in his ears, another guitar may be panned to 2 o’clock, stereo keyboards might be mixed real wide across or not, and some other sources might be panned to 11 o’clock, or 4 o’clock, and so on. While we would usually not do this for a mix intended for an audience, this “un-mixing” by stagger panning can be very effective for stage monitoring. One excellent worship bassist stated:
“When running an IEM system in mono, I hear the mix dead center. That is a problem when I need to hear kick, snare, overhead drum mics, bass, acoustic guitar, electric guitars, click, percussion, back-ground vocals, the worship leader, a choir, loops, etc… I have to choose three to five things to monitor and everything else takes the back seat…”
(he just described clouding from a full mix)
”...when I use IEMs in stereo, I have a much larger sound field to use. I’ll pan background vocals slightly left, the worship leader slightly right, acoustic around 30 percent right, piano around 30 percent left, kick and bass dead center, overhead drum mics around 50 percent right, and so on…”
(sounds like his version of stagger panning)
“With a stereo mix, things don’t compete as much… In mono, the only way to get more room is to increase the gain, which takes my mix louder, whereas a stereo mix allows me to take my mix wider. In fact, I am able to use 25-35 percent less volume with a stereo mix.”—Andrew Catron, associate of worship, Lee Park Church
And here is a quote on this topic from a veteran professional monitor mixer:
“...I’ve found that creating a stereo mix with slight spread of sources with the artist’s own voice or instrument dead center allows me to keep levels under control. I also get a lot less of the ‘more me’ requests with this approach.”—Scott Fahy, lead audio engineer, Living Word Christian Center
While Catron has a good working audio knowledge, he is a musician first and it’s interesting that he sorted out the thoughts above while transitioning from a mono to stereo in-ear mix. Fahy is not a musician but a very skilled and experienced audio engineer, and usually provides several dozen monitor mixes at a time on a dedicated console in a complex worship environment. Both, from very different approaches, are convinced that stereo (vs. mono) in-ear monitoring makes for easier monitoring, happier users, and lower volume.