1) Define the event constraints (quick summary)
- Venue type: indoor / outdoor / covered outdoor
- Audience size and area (people &meters²)
- Music style: acoustic, rock, EDM, electronic (bass needs vary)
- Power availability, noise curfews, permits, and budget range
These four things determine most decisions (coverage, SPL, subs, and rig size).
2) Set target SPL and coverage goals
- Typical target levels at the audience:
- Small club / listening: 90–100 dB SPL (A) peak
- Typical concert: 100–115 dB SPL (A) peak at front-of-house (FOH) listening position
- Loud rock/EDM close to stage: 110–120 dB SPL (peak) — use caution for hearing safety
- Coverage goal: even SPL across the audience area with ±3 dB as a practical target.
Practical acoustics rules:
- Free-field distance loss ≈ −6 dB per doubling of distance from the source.
- Use multiple speaker zones or flown arrays to reduce distance variation and get even coverage.
3) Choose the PA topology: line-array vs point-source
- Line arrays — best for medium → large crowds, flown or stacked arrays give long-throw, even vertical coverage, controllable throw and fewer audience level jumps.
- Point-source (powered mains) — good for small venues and near-field; cheaper and simpler to deploy.
- Hybrid — small mains for nearfield, flown arrays for long throw.
When in doubt:
- <300 people → point-source or small flown arrays.
- 300–2000 → small/medium line arrays or large point systems.
- 2000+ or outdoor → flown line arrays + multiple sub arrays.
4) Subwoofers & low-frequency strategy
- Low frequencies add punch and perceived loudness. For dance/EDM/rock, dedicate substantial sub capacity.
- Use cardioid sub setups (delays & polarity) to reduce stage noise and local neighbor complaints.
- Avoid a single central sub if the audience area is wide — distributed subs often produce smoother response.
5) Match speakers to venue size (cheat sheet)
(Approximate — adjust to taste & budget.)
- Small (≤300 people, small club)
- Mains: 2 × active 12”/15” full-range (or 2 × powered point sources)
- Subs: 1–2 × 18” active subs (mono or dual)
- FOH console: 8–16 channels
- Power: integrated amplifiers in actives or 1–2 kW total if passive
- Medium (300–2,000 people)
- Mains: flown small line array or 4–6 large point sources per side
- Subs: 2–8 × 18” subs (flown/ground stacked arrays)
- FOH console: 16–48 channels (digital preferred)
- Amplification/processing: DSP, limiters, 3–10 kW+ depending on rig
- Large (2,000+ / outdoor festivals)
- Flown line arrays left/right (large modules) + front-fill and delays
- Subs: multiple cardioid sub arrays per side and center (lots of capacity)
- FOH console: 32–96 channels (digital desk with scene recall)
- Power: tens of kW of headroom; pro rig and crew
6) Understand speaker sensitivity & power needs (simple math)
Speakers are rated in dB @ 1W/1m (sensitivity). To get a higher SPL you need more power; every +10 dB requires 10× the amplifier power.
Example: a speaker with 100 dB @1W/1m
- To reach 110 dB at 1 m → need 10 W (10×1 W).
- To reach 120 dB at 1 m → need 100 W (100×1 W).
(Use the formula: Power ratio = 10^(∆dB/10), where ∆dB = target SPL − speaker sensitivity.)
Note: real concerts require multiple speakers and account for distance losses — this example only shows the relationship between sensitivity, dB and power.
7) Amplification & processing
- If using active loudspeakers, amps are built-in — still use external DSP for delay and limits as needed.
- Passive speakers need correctly sized amplifiers (headroom recommended: run at ≤50–70% of amp capability for clean peaks).
- Use digital signal processors (or a digital mixing console) for crossovers, delays, EQ, limiting, and alignment.
- Always engage limiters on FOH and subs to protect drivers.
8) Monitor system
- Stage monitors or in-ear monitors (IEMs). Consider IEMs for higher SPL and reduced stage bleed.
- Wedge monitor counts depend on band configuration. Ensure separate mixes and enough monitor power.
- Use floor monitors with appropriate patterning and time alignment relative to mains.
9) Cabling, connectivity & redundancy
- Use balanced XLR for analog mic/line runs, and AES/AVB/MADI/Dante for digital audio networking.
- Plan for neat cable runs, snake boxes, and labels.
- Redundancy: have spare microphones, DI boxes, snakes, power distro, and at least one spare amp or spare active speaker if possible.
10) Measurement & tuning
- Bring a measurement microphone and RTA/real-time analyzer (or measurement software) and an SPL meter.
- Walk the venue during setup and measure at multiple positions; time-align mains and subs, apply gentle EQ and delay for coverage.
- Aim for smooth frequency response in the audience area, not “flat” at the mix position only.
11) Safety, legal & hearing considerations
- Follow local noise ordinances and curfews.
- Provide ear protection info for staff and audience; consider offering earplugs for high-SPL shows.
- Secure flown equipment (rigging safety is non-negotiable) with certified riggers and load calculations.
12) Budget prioritization (how to spend wisely)
- Speakers & subs — main investment for sound quality.
- DSP & mixing console — important for control and consistency.
- Monitors/IEMs & microphones — directly affect performers.
- Amplification/cabling/rigging — don’t cheap out — reliability matters.
- Measurement tools & technician — yield the biggest improvement in perceived sound for the money.
13) Setup & day-of checklist (short)
- Load-in / inventory check (speakers, subs, amps, mics, stands, cables).
- Power distro and grounding check.
- Position speakers & subs; rig safety check.
- Line check (all mics & DI).
- Gain structure & soundcheck with musicians.
- Measurement sweep, align delays, set limits.
- Walk the audience area and tweak.
- Confirm monitor mixes and talkback.
14) Common pitfalls & fixes
- Boomy low end → reposition subs, use high-pass on mains to let subs breathe, apply EQ, and consider cardioid sub array.
- Hotspots/cold spots → add delay fills or better speaker splay; fly arrays or add fills to flatten coverage.
- Feedback → trim monitor levels, use directional mics, high-pass on inputs, and use notch filters sparingly.
- Insufficient headroom → get bigger speakers/subs or add more boxes; limiters help avoid clipping but don’t replace headroom.
15) When to hire pros
If you’re doing a large outdoor show, multiple stages, high SPL requirements, or complex rigging — hire a pro audio company and a rigging/FOH engineer. The cost of a bad show (or worse — unsafe rigging) far exceeds hiring experienced people.
Quick next steps I can do for you (pick one)
- Give me venue type + audience size + indoor/outdoor and I’ll suggest an explicit equipment list and rough budget.
- Or, I can produce a one-page rig spec for small / medium / large shows you can hand to a vendor.
