In-ear monitors (IEM)

An in-ear system is a bodypack receiver feeding moulded or generic earpieces, fed by a transmitter at the monitor position. Each performer hears their own mix at their own level, isolated from the room.

The gains are real and they compound. The stage gets quiet, so the open microphones pick up less of everything that is not the person in front of them, so the main system sounds cleaner and can be turned up further before anything rings. A performer also hears the same mix every night regardless of the room, which is why touring acts rarely go back.

The cost is spectrum, and it is the part that gets forgotten at the planning stage. An in-ear transmitter occupies frequencies in the same bands the wireless microphones are using, and it transmits continuously rather than only when somebody is speaking. Eight channels of in-ears and twelve channels of microphones is a twenty-channel coordination problem, not a twelve-channel one.

The other cost is isolation. A performer sealed into earpieces cannot hear the room, which is disconcerting for a speaker who has never used them and is usually solved with a pair of ambient microphones out front fed quietly into the mix.

Event audio production — owned inventory, our own crew, and a site survey before anything is specified.

• Monitor wedge The angled loudspeaker on the deck pointed back at a performer — the oldest way to let somebody hear themselves, and the one that sets the ceiling on how loud a microphone can go.
• Wireless microphone A microphone with a radio transmitter instead of a cable — legal in a narrower slice of spectrum than most people assume, and not something to buy by channel count alone.
• Frequency coordination Choosing an operating frequency for every wireless device on site so that none of them, in combination, lands on top of another — the work that decides whether the microphones hold.