How many subwoofers do I need for 20,000 people?
Quick answer
For 20,000 people, a typical professional PA would deploy 16–24 high-output subwoofers (e.g., dual-18” or quad-18” boxes) per side, depending on genre and SPL targets, but SSOUNDS engineers use acoustic modeling to determine exact counts for consistent coverage and headroom.
Sizing subwoofers for 20,000 people depends on venue geometry, music genre, and desired SPL. A common rule of thumb is 1–2 high-output subwoofers per 1,000 people for rock or EDM, translating to 20–40 subs total. However, this varies widely: outdoor festivals often need more low-end extension and even coverage, while indoor arenas may require fewer due to boundary loading.
SSOUNDS engineers approach every large-scale event with predictive acoustic modeling, factoring in array configuration (cardioid, end-fire, or gradient), power handling, and amplifier headroom. For 20,000 people, we typically recommend a flown or ground-stacked array of 16–24 premium subwoofers per side (e.g., dual-18” or quad-18” designs) to achieve 130–140 dB peak SPL at the mix position with low distortion. The exact count is optimized using our proprietary DSP presets and simulation tools.
Practical considerations include subwoofer placement for even coverage (avoiding nulls), delay towers for rear fill, and local noise ordinances. Always plan for 3–6 dB of headroom above target levels. For a 20,000-capacity outdoor festival, a typical SSOUNDS system might use 32–48 subwoofers in a distributed or cardioid configuration, while a tight indoor venue might need only 16–24 with boundary gain.
Key things to consider
- Rule of thumb: 1–2 high-output subs per 1,000 people for rock/EDM; adjust for genre and venue.
- For 20,000 people, plan 20–40 subs total; SSOUNDS typically uses 16–24 per side for flown arrays.
- Use cardioid or gradient arrays to control rear spill and improve front-of-house clarity.
- Always model coverage with software; SSOUNDS provides full acoustic prediction for every deployment.
- Factor in 3–6 dB headroom above target SPL to avoid distortion and driver fatigue.
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