Key Takeaways
- An AV specification must be room-specific — the same specification deployed in two different rooms produces different results
- Signal flow (how audio and video signals travel from source to display and speaker) must be documented — undocumented signal flow produces mysterious failures that take 40 minutes to diagnose
- Screen sizing is calculated from the most distant viewing position, not from aesthetic preference
- Microphone count must include all sources: presenters, panellists, audience Q&A, MC, and any off-stage sources
- The AV specification should be issued to the venue before the production contract is signed — venue exclusivity and in-house system compatibility must be confirmed
Room dimensions and display sizing
The first page of an AV specification contains: room dimensions (length, width, ceiling height), seating configuration and approximate density, the viewing distance from the screen to the furthest seated delegate, and the ambient light level. These four inputs determine: the display technology (LED wall or projection), the screen size (the furthest viewing distance divided by 8 gives the minimum screen height in metres — a 24-metre-deep room needs a minimum 3-metre-high screen), the projector output in lumens (or the LED wall brightness in nits for a given ambient light level), and the PA system type (point-source or line array depending on room geometry).
Signal flow documentation
A signal flow diagram shows how every source (laptop, playback device, microphone, camera) connects to every destination (FOH PA speaker, confidence monitor, LED wall, recording device). It does not need to be an elaborate schematic — a clear table with source, device, and destination for each signal path is sufficient. The purpose: when a signal is not reaching its destination on show day, the signal flow document tells the AV engineer exactly which cable, device, or connector to check. Without a signal flow document, the diagnosis is exploratory — and the exploration takes time that is not available on show morning.
Microphone specification
A complete microphone specification for a 500-person conference lists every microphone required: lectern microphone (type — boundary, gooseneck, or podium condenser), presenter wireless lapel or headset (quantity), panel microphone (quantity and type), audience Q&A handheld (quantity), and MC handheld (quantity). The total channel count from this list determines the minimum console input requirements. Add 20% to the channel count for contingency — a 20-channel microphone list should specify a 24-channel minimum console. A conference that discovers on load-in morning that the console has fewer inputs than sources is a conference that will run its technical rehearsal with something broken.