Enter your Speaker Sensitivity, Amplifier Power, Distance to Listener, and a few speaker setup details — like Number of Speakers and Speaker Placement — and this Decibel SPL Calculator works out your Peak SPL along with exactly how much each factor (distance, power, quantity, and placement) is adding or shaving off your final sound pressure level.
Peak SPL
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Distance Loss
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Power Gain
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Speaker Quantity Gain
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Placement Gain
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SPL from Pressure
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Sound pressure level (SPL) is a measure of sound pressure relative to the human hearing threshold, expressed in decibels (dB). It quantifies how loud a sound appears to our ears.
SPL is calculated using the formula SPL = 20 × log(P/Pref), where P is the sound pressure in pascals and Pref is the reference pressure of 0.00002 Pa (20 micropascals).
SPL decreases by 6 dB for every doubling of distance from the sound source, following the inverse square law. This is why moving farther from speakers reduces the perceived volume.
Speaker sensitivity measures how loud a speaker will be with 1 watt of power at 1 meter distance. Higher sensitivity speakers (90+ dB) produce more sound with less power than low sensitivity speakers (80-85 dB).
Speaker placement near boundaries (walls, corners) increases SPL due to acoustic reinforcement. Free space has no gain, while corner placement can add up to 9 dB.
RMS power is the continuous power a speaker can handle, while peak power is the maximum instantaneous power. Use RMS values for accurate SPL calculations as they represent real-world performance.
Each doubling of identical speakers adds 3 dB to the total SPL. Two speakers add 3 dB, four speakers add 6 dB, and eight speakers add 9 dB compared to a single speaker.
Prolonged exposure to levels above 85 dB can cause hearing damage. 90 dB is safe for 8 hours, 100 dB for 2 hours, and 110 dB for only 30 minutes according to OSHA guidelines.