This is what I’ve learned so far…
So you get this phone call.
“DUDE! Guess what! We just bought new ear monitors for the band!”
“Huh?”
“Yeah! And we fired that loser monitor dude too. You’re gonna mix monitors! It’ll be GREAT!”
Thus begins your journey into the world of ‘ear monitors’. The house engineer thinks it’s cool. The band isn’t sure. The accountant wants you to send the whole rig back. And you don’t even like headphones.
Fear not, for the voodoo to do is not hard to learn. Simply put, ‘ear-monitoring’ systems are yet another tool for curing stage ailments. But they are neither an easy fix nor a cure-all. EM’s are not significantly superior to floor monitors, indeed they present a vast range difficulties of their own, as many artists and engineers have found. However, they certainly have advantages over traditional monitoring systems and, used properly, can provide benefits besides simply making life easier for the FOH engineer.
My own experience with EM’s has been a series of hypotheses and experiments, some more successful than others. The goals that inspired these modern monitoring systems have spawned multitudes of approaches to their use. And I have seen other engineers grappling with the same problems in different ways. But there are a few things that I’ve learned….
The primary concerns of mixing ear monitors are fairly simple. First is audibility (duh…). The desire to achieve clarity and consistency is the artist’s primary concern and motivating factor in purchasing an EM system most of the time. That and looking cool.
Second (and no less important), is safety, specifically the protection of ears that might be worth millions of dollars. Musicians should be responsible for being aware of their volume levels and liability for hearing damage, but it is imperative their engineers make musicians aware of the risks they run (and in my opinion, negligent if they do not). I have found most professional musicians are concerned with protecting their hearing and are usually willing to try to adjust their habits to do so. (Until showtime anyway.)
Where to start? I try to set an ear monitor level with the artist’s vocal mic that sounds more or less the same as when I speak loudly in a quiet room. This is usually at or about the maximum undistorted output level of the wireless system. Then I adjust the compression so that a strong signal crosses slightly past the compression threshold, and a full-on scream goes deeply into compression.
It is not impossible to hear EM’s at this volume.
The usable limit of spl at the eardrum is not only finite; it is something to which people become accustomed. I have several clients who have trained themselves to be comfortable with volume levels that are only a step below detonation of a small high-explosive device. Helping them to lower their comfort threshold is a delicate political negotiation, but it is something which a conscientious engineer will at least mention now and again. The only reason one thinks one needs more volume is external masking. Anything louder is only going to cause further damage to hearing.
The appearance of these EM systems several years ago was met with great joy by many FOH mixers, who dreamily envisioned silent stages and pristine studio-with-customers mixing conditions. That sort of thinking has by and large proved itself unrealistic. While removing amplified signals from a stage can make for a cleaner audience mix, it is more often counterproductive from the musician’s (and the audience’s) standpoint. (Musicians spend years moving air with speakers; to say they become accustomed to the sounds and tonal characteristics of amps and speakers is a gross understatement.) Stages without amplified signals are often unnatural and sterile from the musician’s standpoint, and actually it’s pretty weird to sit on the front row and hear no sound coming off the stage except the drummer’s cymbals.
The notion started from the opposite extreme – some bands were (and should be) so loud FOH engineers are forced to use the PA for just for kick, snare and vocals. That sort of thing can still be a problem with EM’s. For example, when a vocal mic is boosted to the point such that a 105 db signal has an apparent volume of 120 db (15db of amplification in the EM’s), then the 95 db of ambience in the room has an apparent volume of 110 db. This factor goes almost unnoticed by people using floor wedges, but it can be the EM engineer’s worst nightmare.
A show where the house PA or the band’s instruments create spl’s greater than about 105 db at the vocal mic usually creates the necessity of chasing the artist’s vocal mic plus-or-minus 6 or 12db to prevent the mix from sounding like a train wreck when the artist steps away from the mic. Of course, if a singer puts out 110 db of vocal but the ambient sound pressure at the mic is 115db, you’re fighting a losing battle – the only choices are telling the singer to sing louder (sure to get you fired) or going back to floor wedges and cramming earplugs in the singer’s ears while espousing the virtues of ‘head voice’ (a technique in which a singer listens inside their head and forgoes the monitor – also likely to get you fired.) -Ear monitors cannot fix this. Don’t try… you’ll only spend a pile of money and frustrate yourself. (Go to Vegas if you want to do that.) However, ear monitors can be used to amplify a weak vocal, provided the engineer has time to ‘chase’ the mic with each vocal line, or the ambient stage volume is sufficiently low.
This is the first significant difference between traditional stage monitors and ear monitors. While floor (or ‘open’) wedges just sit there (if they’re lucky), ear monitors follow the artist around on a stage. The trash rolling around from open mics on loud stages plays a large role in a band’s success (or lack thereof) with ear monitors. This also relates directly to how we hear and what the process of hearing actually is. Although we hear with our ears, this is only the beginning of our ablility to hear. Everybody knows how we feel very low frequency response more than we hear it, but it seems many people fail to recognize how much of the rest of the audible range is perceived in places besides our ears.
The most important mixing mantra for an EM engineer is to try to create a totally transparent illusion. (I personally prefer the shows where the star never even thinks about the monitors; when the illusion is so complete it seems as though there are no monitors at all.) The creation of a transparent image requires the engineer to compliment the sound already present at an artist’s position on stage. This means assessing whatever is rolling around the stage, the room and the artist’s head – then attempting to fill in only enough holes to make it feel natural. (Obligatory cliche – It’s not what you put in, it’s what you leave out…)
Which leads to the second major difference between floor wedges and EM’s, reverberance. A person’s perception of reverb in daily life is usually only noticed when they move to or from an extremely reverberant place. Until then room reverberance goes almost unnoticed. Reverb exists in every environment however, and this must be simulated. The primary function of a reverb in an EM mix is to bridge the gap between the artist’s head and the PA system. Ear monitors tend to sound muddled when the mix is too dry, or the reverb’s decay time is too long or too short. The yardstick for a proper EM reverb setting is the sound of the environment in which they will be used.
Other common mistakes in ear monitoring are rooted in and around this ‘psychology of hearing.’ Most engineers are familiar with the concept of ‘visual acoustics’ – the thing that makes a musician dislike a monitor before it is even turned on – and many employ that concept in their approach to mixing. However, the reality of the situation is that by and large musicians are right about their problems onstage, even if they can’t find a way to express it. Troubles usually arise when an engineer fails to account for circumstances the musician experiences.
For example, what sound can one hear which is nearly always centered in one’s field of hearing? What other things happen along with that sound? Your voice is the only sound that you hear so consistently. It also causes increased pressure in the nasal cavity and eustachian tube, which changes the way things sound when we speak (or more importantly, sing.) Did you ever notice how hard it is to hear anyone else speak when you’re yelling as loudly as possible? Not only because you’re voice is loud but because your own voice decreases the efficiency of your hearing ability. This is one of the first things one should discover about EM’s.
If a microphone is set up for a primary vocal and adjusted it so that it sounds loud and full-bodied for your voice, the odds are your artist will seem so (comparatively) loud it will make your head ring when they belt out the first line of vocals. Yet they may ask you for more.
The psychology of this situation is that there is no properly timed external sound pressure to provide a reference for the person singing, therefore the sound is not perceived as loudly. Reverberance from the house PA usually exacerbates this phenomena, as it is delayed and usually lacking any discernable high-end components, which serves to muddle a person’s perception of what they hear. Artists are often surprised to hear how loud someone else sounds when singing through the same mic, yet the mic still doesn’t seem loud enough.
There are two factors at work in this phenomena, which relate two our two primary hearing sensations, pressure intensity and phase correlation. One factor is compression. Not electrical processing type compression, this is the compression caused by the pressurization of one’s head by one’s own voice – natural, normal and almost unnoticed. The other factor is phasing and reverberation, more specifically our perception them. The trick is making these two concepts work for you instead of against you.
We are working with people, so it is important to remember to think of a room (or other environment) as a mono sound source; only people are stereo. The stereo image produced by a digital reverb is created by setting slightly different delay times (less than 5 milliseconds with variances in microseconds) for different frequencies of the reverberating signal (with respect to left and right) and mixing them with the original signal. This is the concept of what you hear referred to as the unit’s algorhythm; basically it emulates the perceptual characteristics of an actual reverberative space. (HANDY TIP: If it’s weird, flip its phase. It can’t hurt, you can always flip it back, and sometimes it actually helps.) But people hear with their ears and their bodies, and accommodating both is very important.
As a matter of practice, EM mixes need to be tailored to the type of instrumentation they’ll be monitoring. For example, most guitarists hate the way their guitar sounds through EM’s. This results from the fact that a tone that should be coming from a 10 or 12 inch speaker and moving a bunch of air (and shaking your insides) is being pushed through a driver that is 2.5 mm in diameter. It sounds bad. The key is approach, (and this is very important): For a vocalist EM’s are monitors, but for a guitarist (or a drummer, or other loud players) EM’s are protection. The reason why an engineer can’t make their EM’s sound like a Marshall stack should be obvious, but I have seen them trying to do it time and time again. My advice is turn the amp up and, as we say in Georgia, “let it eat.” Then cram those EM’s in and just put in enough guitar to replace the brightness of the signal that is blocked by them. (Mmmmm, rock and roll….)
Many artists have signal compressors attached to their system to prevent system-overload or other accidental ear-splitting incident, but the usefulness of these compressors is often less than optimal. A full bandwidth compressor does not properly address the selective abilities of the ear. And often by the time it acts on that spike that lights up the boss’s eyes, the ear moulds are already on the floor and the engineer is headed home – because any slope and threshhold one selects will either grab the signal too often and obviously on program peaks, or it will act too late and insufficiently.
A better approach is finding a multi-band compressor, and letting it work. A properly set compressor can be used to allow high and low components of an EM signal to pass unaffected while compressing the portion of the signal in the vocal range. The effect is like a selective ducker, i.e., the mid-range portion of a program’s material is compressed when a vocalist sings (complimenting the natural compression of their own head), while allowing the peripheral frequencies to remain consistent. The illusion is that of a vocal clearly cutting through the program material. While the measurable energy of the signal does not change drastically, the vocal seems to push through the signal, even though there is no significant increase in the overall volume of the signal. The other advantage of course is that an errant signal gets squashed, and well before you’re looking for a new gig.
Once a mix is safe and smooth, a few details like panning and reverb will finish the basic image. When mixing dry vocal with a reverb return there will be phasing anomalies which result in the signal image drifting from side to side as the pitches (frequencies) of the signal change. What does this mean to an engineer? How do you fix this? Aaaaa, I never sweat it much; just try to keep it close. It is a normal effect in a reverberating room. However, I cannot emphasize the following enough. Thou shalt not never ever center no signal save thine own vocal. All other signals should be at least ever-so-sligthtly off center; the louder that something shows up right in the middle of your head the more it confuses the audibility of the signal. Panning doesn’t have to be drastic, just a hair to either side is fine. As a signal becomes heavy to one side or another there is an noticeable illusion that the primary signal (the artist’s voice or instrument) moves to the opposite side. I usually only compensate for this effect when it affects a singer’s voice.
At this point I’d like to point out that I personally dis-approve of anyone using one ear monitor instead of two. I’ve heard plenty of excuses for wanting to do this (and I’ve seen many artists doing so) but it is extremely dangerous. The brain simply cannot process information so un-natural and abnormal as one EM will produce, and un-healthy requests will always result. I’ve suggested to that clients who wish to use only one EM that they sign a release indemnifying me for their inevitable hearing loss. It’s roughly the same thing as strapping a double-fifteen-by-two-inch wedge on their shoulder and cranking it to full volume. I’ve also heard rumors of a few lawsuits stemming from this practice. EM’s are really for protection, and borrow heavily from audiologists and their work with people who are already losing their hearing; protection should always guide the engineer’s technique.
One must decide how to match the program to the environment where it will be used. A person subconsciously gleans all types of information from reflected sound and the phase differences that the fixed six-or-so-inch distance from eardrum-to-eardrum can detect. Humans learn to find the source of a sound easily, but few realize it is the phase relation of the signal reaching each ear which allows us to determine not only a source location, but helps make subconscious assessments of the environment we’re in as well. (It is not only the volume difference from one side of your head to the other that makes you look when someone calls your name.)
Try not to use a mono signal when a stereo signal is available – if one is not available, you can fake it. One of my favorite EM tweaks is using a ‘y’ cable to send a mono acoustic guitar to two channels in my console. By reversing the phase of one signal (and therefore one ear) a stereo image is created in the brain. A little minor eq to simulate the richer low-mids in one ear and some sibilant finger noise in the other makes a very natural sounding acoustic image. While one’s ears are rarely 180 out of phase, the brain sees a signal coming in one ear while going out the other, and puts the information together the only way it can. (I have one client who uses one half of his entire mix out-of-phase with the other – we split his vocal channel and re-phase it normally. It was easier than splitting all his instruments which are mono sources into two channels.)
It is also imperative that one study the gain structure of their system. It is a delicate balance when one achieves the just-so point of a console-compressor-reverb-EM system, and it varies slightly from day-to-day and venue-to-venue. I’ve found it helps my rig’s consistency to insert the main mix compressor for an EM mix at the console’s output insert point, and using only the console’s onboard equalizers. This allows setting gain structure much more accurately than simply placing the compressor inline before the EM system.
I also use compressors on reverb outputs to keep a lid on the sibilance spikes I get from occasional ‘s’s and such. (Yes, those are ART reverbs….) I’ve found a short enough release time allows the verbs to sound really bright and wet without overdriving the EM system’s front-end. Then after throwing in a few handfuls of the usual gates ‘n’ comps ‘n’ stuff… a rig can get pretty complicated. Just remember, simpler is better, but better ain’t always simple.
Ear monitors have plenty of diehard fans… and plenty of former users. They are here to stay I think, but they’re definitely not for everyone. It’s just important to remember that they’re very different from floor monitors – and they aren’t cheap. I’ll go one further and say I do recommend them for nearly everyone who sings.
But don’t call me if you don’t like ‘em….
Copyright © 1997 JPArmstrong