RACK/LEVEL & SPL

P_{req}

Amplifier power

Find the power you need to reach the back of the room.

Inputs

YOUR SYSTEM

Target sound level

70130

Speaker sensitivity

80115

Listening distance

0.5100

Headroom

020

Result

METER

Required amplifier power

1,128W

Per loudspeaker, at the selected distance

Without headroom

565W

Headroom factor

2.00x

Peak target

103.0dB

Power vs. distance: Point-source model

How it works

Size your amplifier for the job.

This reverses the SPL equation. Your target level, speaker sensitivity and distance determine continuous power; the headroom setting adds a margin for peaks.

The formula

P = 10^{\frac{L - S + 20 \log_{10}(d) + H}{10}}

$L$ — target level in $\text{dB SPL}$
$S$ — sensitivity at $1\,\text{W}$ / $1\,\text{m}$
$d$ — distance in meters
$H$ — headroom in $\text{dB}$

Worth knowing

An extra 3 dB takes approximately twice the power. Improving speaker sensitivity by 3 dB cuts the required power in half.

Assumptions

The calculated power may exceed your speaker rating. Check continuous and peak limits, amplifier impedance capability, and set protection limiters. Power compression is not modeled.

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SPL Throw & Headroom Power & voltage Impedance & Cable Loss