Part 2 – System gain requirements
• Directivity
• Outdoor sound systems
• How much gain is needed?
, Directivity index
Polar plots, beam-width, DI plots, iso bars
Using directivity information
Combined radiators
, Most sound sources are directional to some extent, (they are louder in one direction). We
need to understand the sound radiation pattern each speaker, as well as their interactions
in a multi-component system.
We can compare this with a hypothetical omnidirectional sound source in a free field,
producing a constant SPL. We measure the SPL at a fixed distance (L) with a mic.
Each reflective surface we add (at A, B, C, and D) halves the radiation angle, and so doubles
the acoustic pressure (+6dB) at the microphone position.
• Directivity
• Outdoor sound systems
• How much gain is needed?
, Directivity index
Polar plots, beam-width, DI plots, iso bars
Using directivity information
Combined radiators
, Most sound sources are directional to some extent, (they are louder in one direction). We
need to understand the sound radiation pattern each speaker, as well as their interactions
in a multi-component system.
We can compare this with a hypothetical omnidirectional sound source in a free field,
producing a constant SPL. We measure the SPL at a fixed distance (L) with a mic.
Each reflective surface we add (at A, B, C, and D) halves the radiation angle, and so doubles
the acoustic pressure (+6dB) at the microphone position.
