# SPL (Sound Pressure Level) Calculator

This tool calculates the SPL at a specified distance away from an amplifier speaker combination.

Enter

• Speaker Sensitivity (usually specified in dB (1W/1m)
• Amplifier Power (Watt)
• Distance (meter or feet)

## Background

### Speaker Sensitivity

It is a measure of how well power to a speaker is converted to sound energy.

As an example, the sensitivity of a speaker might be rated as 85 dB (1W/1m). This means that speaker produces a level of 85 dB at a distance of 1 meter, when driven with an amplifier that provides 1 Watt of power.

The higher the number in dB, the more sensitive the speaker and the more efficient it is in converting the power output of an amplifier to audio.

### Amplifier Power

The output power of an amplifier is specified in Watt. It is important to review the specifications carefully and use the root-mean-square (RMS) power for this calculation. You might see the peak power advertised by some manufacturers as this is a larger (and more impressive) number. Don’t use the peak power for this calculation as it will provide an unrealistic estimate.

### Distance

This is simply the distance away from the speaker (not the amplifier) where you want to find the SPL.

## Example Calculation

Consider a 100 Watt amplifier that connects to a speaker with sensitivity of 85 dB (1W/1m).

The amplified SPL at 1 meter is 105 dB. (This makes sense when you consider that 100 Watt converts to 20 dB gain).

At a distance 20 meters away, the SPL is approximately 79 dB. The attenuation relative to the speaker sensitivity is around 6 dB.

Without the amplifier the loss would be 26 dB.

## Related Calculators

• Amplifier Speaker Matching – Find the amplifier gain (Watt) required to meet a target sound level at a specified distance from the speaker
• Max SPL Calculator – explore the limits of your audio equipment
• Add Sound Pressure Levels – this tool makes it easy
• SPL Attenuation – A speaker’s data sheet usually specifies the SPL at 1 meter distance when the amplifier provides 1 Watt of power. This tool provides the formula and also calculates the attenuation at a specified distance away from the speaker.