The Silent Stage Left Monitor
You are the audio operator for a 600-seat theatre hosting a four-piece band plus a guest vocalist. The system is a digital console with a stage rack, four monitor mixes on wedges, and a wireless handheld for the guest. During soundcheck the guest vocalist's wireless cuts out intermittently, but only when she walks to stage left. The lead guitarist's wedge has been squealing all afternoon and he keeps asking for 'more me'. The console shows the wireless receiver at full RF but the audio meter drops to nothing during the dropouts. The show starts in ninety minutes and the venue has no spare wireless channel licensed for this location. The theatre's walls are thick stone and the stage-left wing has a steel fire door that is usually propped open.
1. Diagnose the wireless dropouts and the wedge squeal, explaining what the symptoms tell you and what you would test first.
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Wireless dropouts with full RF but no audio point to a different fault than a true RF dropout. If the receiver shows strong RF but the audio meter falls away, the carrier is arriving but the audio is not. Possible causes: the transmitter's mute or power switch being knocked, a failing capsule or cable at the transmitter, companding or squelch behaviour, or the receiver's audio output stage. However, the fact that it only happens at stage left is the key clue. That suggests a positional factor: a reflective surface, a body absorbing the signal, or interference from a source local to that wing.
The propped steel fire door is a strong suspect. A large steel mass near the performance area can create a multipath reflection that arrives out of phase, and it can also act as a shield. Test by closing the door and repeating the walk test. Also scan the RF environment at stage left with the receiver's spectrum analyser, checking for a local interferer such as an LED driver, a dimmer rack or a video wall.
The wedge squeal is classic feedback: a loop between the microphone or instrument pickup and the wedge. The guitarist asking for 'more me' is the wrong fix; more gain increases the loop. Ring out the wedge: bring the channel up slowly, identify the offending frequency on the console's EQ, and notch it narrowly. Check the wedge's aim and the mic pattern. A cardioid mic pointed at the wedge, or a wedge aimed into the mic's rear lobe, will feed back early.
2. With ninety minutes to show and no licensed spare channel, what are your options, and how do you decide?
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Options, in order of preference:
Fix the physical cause. Close or secure the fire door, reposition the receive antennas to line-of-sight with the stage, or move the receiver rack. This costs no channel and may solve it outright. The fire door must not be propped open during a performance anyway, so this is a compliance win as well as an audio fix.
Change the transmitter or capsule. If the dropout is a transmitter fault, swapping the handheld body for a known-good unit on the same frequency resolves it without a new licence.
Use a wired microphone for the guest. A cable is unglamorous but reliable, and a 600-seat theatre has room for a discreet cable run. Confirm the guest can work with it before committing.
Re-tune to a clear frequency within the licensed band. If the venue's licence covers a range, a coordinated frequency within that range is legal. Do not transmit outside the licensed band under any circumstances.
Decision criteria: reliability for the performer, legal compliance, and time. Rule out the free physical fixes first because they are fastest and lowest risk. If the walk test still fails, go to the wired mic and tell the guest and stage manager early so choreography can adapt. Never leave a known-intermittent wireless in the show without a plan and a backup.