Speaker sensitivity

Sensitivity is how efficiently a speaker turns power into sound. A rating of 88 dB means 88 dB SPL at one meter with 2.83 V (one watt into 8 ohms) applied. Ratings may be anechoic or in-room, so compare like for like.

Power scales logarithmically: a speaker 3 dB more sensitive needs half the power for the same volume, and 6 dB is a factor of four. In a large room or at reference level, sensitivity often matters more than amplifier wattage.

Each doubling of power adds 3 dB, and level falls about 6 dB per doubling of distance. An 88 dB speaker at 3 m needs about 100 W for 105 dB peaks; a 91 dB speaker needs about 50 W.