AudioCalcs
PA Speaker Calculator — System Sizing for Venues
Calculate PA system requirements based on venue size, audience and music type.
How We Calculate This
Required power = 10^((target SPL - sensitivity + distance loss) / 10)
Speaker sensitivity is typically 96 dB at 1 W/1 m. Sound level drops 6 dB per doubling of distance (inverse square law).
Delay timing = (distance to delay speaker / 343 m/s) × 1000
Outdoor venues require 2-3× more power than indoor due to lack of reflected sound energy.
Frequently Asked Questions
As a rough guide: speech = 1-2 W/person, acoustic music = 3-5 W/person, full band = 5-10 W/person, DJ/dance = 10-15 W/person. Outdoor events need 2-3x more power than indoor because there are no reflective surfaces to help.
For speech-only events, subs are unnecessary. For acoustic music, they add warmth but are optional. For full band, DJ or dance music, subs are essential for the low-end impact below 100 Hz that tops cannot reproduce effectively.
Headroom is the extra power available above your normal operating level. 6 dB of headroom means your system can handle peaks at 4x the average power without clipping. This prevents distortion on transients and protects speakers from damage.
Delay speakers (also called fills) are needed when the main PA cannot cover the full venue depth with consistent SPL. Typically when the throw distance exceeds 20-25 m. They are time-aligned to the main PA to maintain coherent sound.
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Last updated: March 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.