Problem Solving and Troubleshooting Flashcards

A sound system produces a consistent buzz that changes pitch when a dimmer board in the room is adjusted. The most effective solution is:

Answer: Isolate audio circuits from dimmer circuits and use audio-grade power conditioning

Dimmer boards introduce switching noise and harmonics onto AC power lines; separating audio circuits and using power conditioners eliminates the interference.

After a firmware update to a DSP, all preset scenes fail to load. The most appropriate first step is:

Answer: Check the firmware release notes for preset compatibility changes and re-import scenes

Firmware updates sometimes change preset file formats; checking release notes and re-importing or converting scenes is the correct first response.

A cardioid microphone on a podium picks up excessive low-frequency room noise. The best corrective tool on the console is:

Answer: A high-pass filter set appropriately below the voice fundamental

A high-pass filter removes low-frequency rumble and noise below the voice's fundamental frequency without affecting speech intelligibility.

Two wireless microphone systems on nearby frequencies cause intermodulation products that land on a third system's frequency. This is best resolved by:

Answer: Recalculating and assigning intermod-free frequencies using coordination software

Intermodulation is solved by using frequency coordination software to calculate and assign frequencies that avoid IM products on active channels.

During playback from a laptop via USB audio interface, the audio has a consistent crackle that worsens with CPU load. The most likely cause is:

Answer: Audio buffer size set too small, causing underruns under CPU load

Crackling that worsens with CPU load is the hallmark of audio buffer underruns caused by a buffer size too small for the system to handle.

A speaker cabinet's high-frequency driver fails repeatedly in a system that has been in service for years without issue. The most likely systemic cause is:

Answer: A failed amplifier channel that is producing DC offset on its output

Repeated HF driver failures indicate DC on the amplifier output, which destroys voice coils by applying constant current rather than AC audio.

A system's delay speakers are causing a pre-echo effect where listeners hear the delays before the main system. What corrective action resolves this?

Answer: Add additional delay time to the delay speakers so sound arrives after the main system

Pre-echo occurs when delay speakers fire before the main PA wavefront arrives; adding delay time aligns them to arrive slightly after the direct sound per Haas effect principles.