Speaker Tools

SPL per Watt Calculator

Calculate the expected loudness of a speaker in dB at 1 meter based on sensitivity and amplifier power.

Expected SPL at 1m

108 dB

Tool Overview & Purpose

The SPL per Watt Calculator estimates speaker loudness based on sensitivity and applied amplifier power. It is used for designing sound systems, matching speaker levels, and avoiding underpowered or overpowered setups.

  • Predict speaker output in decibels (dB) at 1 meter.
  • Match speaker loudness in multi-speaker setups.
  • Ensure amplifier power is suitable for desired SPL.
  • Avoid overdriving speakers and reduce distortion.

Who This Tool Is For

  • Audio engineers and system designers
  • Sound system installers
  • Home audio enthusiasts and DIY builders
  • Musicians planning stage or studio setups

Core Audio Concepts

  • Speaker Sensitivity (dB/1W/1m)
  • Amplifier Power (Watts)
  • SPL Increase: doubling power adds ~3 dB
  • Inverse Square Law for distance SPL drop
  • Reference distance (1 meter)
  • Peak vs RMS levels

How the Calculator Works

Formula: SPL = Sensitivity + 10 × log10(Power / 1 W)

Example: Sensitivity 88 dB/1W/1m, Power 100 W → SPL = 88 + 10 × log10(100) = 108 dB

Example Calculations

Speaker Sensitivity Amplifier Power Calculated SPL (1m)
88 dB/1W/1m 50 W 95 dB
90 dB/1W/1m 100 W 110 dB
92 dB/1W/1m 200 W 118 dB

Frequently Asked Questions

SPL per watt is the sound level produced by a speaker for every 1 watt of power at 1 meter.

Use the formula: SPL = Sensitivity + 10 × log10(Power).

SPL is logarithmic; doubling power gives a small perceived increase in loudness (~3 dB).

Yes, you can calculate individual speaker SPL to match loudness across all units.

SPL drops by 6 dB each time the distance from the speaker doubles (inverse square law).

While it predicts loudness, actual damage depends on speaker power handling and clipping.