A measurement of how well a speaker converts amplifier power into acoustic energy—in other words, how loud the speaker can play with a given amount of amplifier power.
SVS specs the sensitivity of its loudspeakers in dB with a 2.83V drive level at 1 meter anechoic from 300-3000 Hz.
Typical sensitivity values range from about 85 dB-92 dB. The higher the number, the louder the speaker will sound with a given amount of amplifier power. But it is not a reflection of the sound quality of the loudspeaker.