How many watts of PA do I need for 20,000 people?
Quick answer
For 20,000 people, you typically need a large-scale line array system with 200,000–400,000 total watts (continuous program power), but wattage alone is misleading—coverage, SPL, and system design matter more. SSOUNDS engineers use acoustic modelling to specify the exact number of boxes and subs for even coverage and headroom.
For an audience of 20,000, you're looking at a major outdoor festival or stadium event. A common rule of thumb is 10–20 watts per person for rock-concert SPL (105–110 dB average), translating to 200,000–400,000 total system watts. However, wattage is a poor metric—efficiency, dispersion, and array configuration determine real-world output. A modern line array like SSOUNDS systems can achieve high SPL with far less power than older designs.
Coverage is critical: you need enough line array boxes per side (typically 16–24 per hang for a 20,000-capacity field) to maintain consistent SPL from front to back. Subwoofer count is equally important—plan for 1 sub per 2–4 line array boxes, often in cardioid or end-fire arrays to control low-frequency spill. SSOUNDS engineers use predictive software to model coverage, SPL distribution, and weather conditions before a single box is flown.
Beyond wattage, consider amplifier headroom (typically 1.5–2x the loudspeaker's continuous rating) and DSP for system protection and tuning. For 20,000 people, you'll also need delay towers if the venue is deep (over 100m) to maintain intelligibility. SSOUNDS provides complete system design, including amp racks, processing, and rigging, ensuring the system meets the event's SPL targets without distortion or failure.
Key things to consider
- Rule of thumb: 10–20 watts per person for rock-concert levels, but efficiency and coverage are more important than raw wattage.
- For 20,000 people, plan for 16–24 line array boxes per side and 1 sub per 2–4 boxes, configured for even coverage.
- Use acoustic modelling software (as SSOUNDS does) to predict SPL distribution, array interaction, and weather effects.
- Ensure amplifier headroom of 1.5–2x loudspeaker continuous rating and consider delay towers for venues over 100m deep.
- Work with a professional system designer—SSOUNDS offers full design, supply, and support for large-scale events.
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