Ten everyday tools for planning a system: SPL, power, delay, cabling, acoustics and RF. Everything updates live as you type. Built by the crew at Enchant Entertainment , for planning, not certified measurement.
How loud a box gets at a distance, and whether you have headroom.
SPL = sensitivity + 10·log₁₀(W × boxes) − 20·log₁₀(distance). Inverse-square loss only; ignores air absorption & room gain.
Total load and the amp power to drive it safely.
Program ≈ 2× RMS, peak ≈ 4× RMS. Rule of thumb: amp ≈ 1.5–2× program power per channel into the load. Check the amp's minimum impedance.
Delay & polarity for end-fire and cardioid sub setups.
End-fire: delay the front box by spacing ÷ 343 m/s so output adds forward, cancels behind. Cardioid: reverse polarity on the rear box + delay ≈ spacing ÷ 343.
Delay for fills, delay towers and subs, temperature-corrected.
Speed of sound = 331.3 × √(1 + T/273.15) m/s. Delay = distance ÷ speed. Add this to the further (downstream) speaker so it lines up with the mains.
Current per phase and the generator you need.
Single: I = W ÷ (230 × PF). 3-phase: I per leg = W ÷ (√3 × 400 × PF). Genset kVA ≈ (W ÷ PF ÷ 1000) × surge. Balance loads across legs.
Will your run hold up over distance?
Vdrop = 2 × length × I × ρ ÷ area (ρ copper = 0.0175 Ω·mm²/m). Aim for under 5%. If over, step up a gauge.
How reverberant the room is, and how it'll fight you.
Sabine: RT60 = 0.161 × Volume ÷ (Surface area × absorption). Over ~1.5 s is a fight, add delays, tighten dispersion, point away from hard walls.
A clean, intermod-aware set of frequencies for mics / IEMs.
Greedy picker spacing ≥ 0.4 MHz and avoiding 3rd-order 2-TX products (2a−b). Always confirm against the local ACMA plan and scan on-site , this is a starting point.
Line up your nominal level with the converter's 0 dBFS.
Headroom = (0 dBFS reference) − nominal. Set gains so nominal sits well below clip and even big peaks stay under 0 dBFS. Target ~18–20 dB headroom.
The everyday conversions.
dBu = 20·log₁₀(V/0.775) · dBV = 20·log₁₀(V/1). Combine: 10·log₁₀(Σ10^(Lₙ/10)). Distance: ΔSPL = −20·log₁₀(d₂/d₁) (−6 dB per doubling).
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