How many watts of PA do I need for 20,000 people?
Quick answer
For 20,000 people, you typically need a large-scale PA system delivering 130–140 dB SPL peak, with 24–48 line array enclosures per side and 24–48 subwoofers, depending on venue geometry and coverage requirements.
Sizing a PA for 20,000 people isn't about wattage alone—it's about coverage, SPL, and headroom. A rule of thumb is 1–2 watts per person for moderate levels, but for a concert or festival, you'll need significantly more. Professional systems like SSOUNDS line arrays are designed to deliver consistent SPL across large audiences, typically targeting 100–105 dB A-weighted average at the mix position with 20 dB of headroom, requiring peak SPL capabilities of 130–140 dB.
For an audience of 20,000, a common configuration is 24–36 line array enclosures per side (left/right) flown in hangs, plus 24–48 subwoofers (cardioid or end-fire arrays) for low-end impact. Coverage depends on venue shape: a wide, shallow crowd may need more arrays, while a deep, narrow space requires fewer boxes with longer throw. SSOUNDS engineers use acoustic modeling software to predict coverage and SPL distribution, ensuring even sound from front to back.
Wattage ratings are misleading because they don't account for efficiency or dispersion. A 2,000-watt line array element can cover far more people than a 2,000-watt point source. Instead, focus on system design: flown arrays for line-of-sight, delay towers for long venues, and subwoofer arrays for consistent bass. For 20,000 people, expect a total system power of 50,000–100,000 watts (continuous) from the amplifiers, but the real key is proper deployment and tuning.
Key things to consider
- Target 100–105 dB A-weighted average at mix position with 20 dB headroom; peak SPL 130–140 dB.
- Typical flown line array: 24–36 boxes per side; subwoofer count: 24–48 units.
- Use acoustic modeling (e.g., EASE, Soundvision) to optimize coverage and avoid guesswork.
- Wattage is secondary to efficiency and dispersion; focus on system design and deployment.
- Consider delay towers for venues deeper than 100 meters to maintain intelligibility.
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