Pro Audio
How PA Speakers Project Sound
Getting sound loud is only half the job. Getting it evenly to everyone in the room — front to back, side to side — is what separates a real PA from a loud speaker.
Dispersion and directivity
Every PA speaker has a dispersion pattern — the horizontal and vertical angle over which it spreads sound, often written like 90° × 60°. Controlling that angle (directivity) lets you aim energy at the audience and away from walls and ceilings that cause echo.
How horns shape coverage
The horn around a compression driver sets the high-frequency pattern. A wide horn covers a broad room; a narrow one throws further down a deep space. Choosing the right pattern is how a system stays even instead of blasting the front rows and starving the back.
The inverse-square reality
Sound falls off with distance — roughly 6 dB quieter each time the distance doubles from a point source. That physics is why one speaker can't evenly cover a long room, and why placement and multiple speakers matter.
Placement and coverage
- Height — getting speakers above head height lets sound reach past the first rows to the back.
- Angling — aiming at the audience, not the room, reduces reflections.
- Fill speakers — extra speakers cover wide or deep rooms the mains can't reach on their own.