Professional wireless personal monitors for stage monitoring are designed to seal the ear, acoustically isolating the user from nearby sounds.
When people with normal hearing close off the opening to the ear canal, the loudness of low-pitched sounds (presented by bone conduction) increases.
In audiological terms, this phenomenon is called “occlusion.”
The worship leader experienced a pronounced increase in low and mid-range sounds when he inserted his earphones for the first time.
He didn’t hear much of his voice through air conduction any longer, and most of what he heard was the remaining bassy/muffly sounds of his voice conducted through the bones in his head.
For this reason, vocalists often have the toughest time adjusting to wireless personal monitors—that is, they mostly hear their own voice via bone conduction.
So a vocalist using wireless personal monitors is certainly going to need to hear others on the stage (such as the band or orchestra) in their monitor mix, but usually needs a lot more of their own vocal.
If they do not hear sufficient level of their own voice, the bone-conducted, “muddy” tone of their voice is predominant and they are uncomfortable.
Ever heard a vocalist trying wireless personal monitors for the first time say, “I sound really weird!”? This is probably why.
Instrumentalists using wireless personal monitors do not have the issue of bone-conducted voice in their head, but they do experience the same isolation.
So now we know that wireless personal monitor users are isolated by these ear plugs—err… earphones!—and we must pay very careful attention to exactly what elements are in their mix. They will no longer hear sounds naturally, as they do with wedges. If there is something they want to hear, it must be routed to their monitor mix.
So it becomes critical that the sound tech auditions the monitor mix frequently with earphones of preferably the same type.
And mix adjustments that required four or five “clicks” with a wedge might need only two or three “clicks” in a wireless personal monitor. Sonic details are simply much more obvious. Consider a worship leader with a choir behind him: in a wedge application, he may hear plenty of the choir without any choir being folded back.
But with “ears,” he will certainly want the choir mixed into his ears! So the acoustic isolation offers wonderful control but requires increased attention and effort from the sound tech.
Full Vs Partial Mixes
A full wireless personal monitor mix might sound much like the front-of-house mix, a commercial CD mix, or similar. It will have every element mixed at the proper “finished product” balance.
A partial wireless personal monitor mix intentionally omits non-essential elements (for that particular user!) so that the remaining/critical elements may be monitored clearly, without unnecessary clouding from a “busy” mix.
For instance, a bass player’s wireless personal monitor will certainly have his bass, the kick drum, the basics of the rhythm section, the lead vocal, and maybe a few other things he may request. But it might eliminate the choir mics, orchestra sounds, background singers, or other elements that are not really essential in helping him get the pitch and time cues he requires.
It is often helpful to remind each other (musicians and techs alike) to contrast the terms “listening” and “monitoring,” and remember the purpose of stage monitoring. This can sometimes become a race for the perfect full mix in a user’s wireless personal monitor, when oftentimes on the worship platform that’s really not the point at all!