Speaker SPL from Power Calculator

Why doubling power doesn't double loudness

Speaker sensitivity ratings describe output at exactly 1 watt of input measured at 1 meter - because sound output follows a logarithmic relationship with power, doubling amplifier power only increases SPL by about 3dB, a far smaller jump than intuition might suggest.

Worked example

For an 88dB sensitivity speaker driven by 100 watts:

SPL = 88 + 10 x log10(100) = 108.0 dB SPL at 1 meter

Frequently asked questions

Why does achieving significantly louder sound need so much more power? Since output scales logarithmically, each additional 3dB of loudness requires doubling the power again - going from 100 to 108dB (an 8dB gain) required 100 watts, but reaching another 8dB louder would require roughly 630 watts, illustrating how quickly power requirements escalate for further gains.

Is a more sensitive speaker sometimes a better solution than more power? Often yes - a speaker with 3dB higher sensitivity produces the same SPL with half the amplifier power, which is why speaker sensitivity is just as important a spec as amplifier wattage when planning a sound system.