Sensitivity (Speaker)

Speaker sensitivity is one of the most important specifications for system design because it directly determines the SPL achievable at a given power level. A speaker rated at 99 dB sensitivity produces 99 dB SPL at 1 metre with 1 watt of input. Each doubling of power adds 3 dB, so 2 watts gives 102 dB, 4 watts gives 105 dB, and so on until the thermal or mechanical limit is reached. The standard test signal is 2.83 volts RMS, chosen because it delivers exactly 1 watt into an 8-ohm load. For speakers with different impedances, the distinction matters: 2.83V into 4 ohms delivers 2 watts, inflating the sensitivity figure by 3 dB compared to a true 1-watt measurement. Some manufacturers specify sensitivity at 1W/1m regardless of impedance, which is more honest but requires knowing the impedance. Sensitivity varies dramatically with speaker type. Horn-loaded compression drivers can exceed 110 dB sensitivity. Large-format professional woofers typically rate 96-102 dB. Home hi-fi bookshelf speakers are often 84-88 dB. The efficiency difference is enormous: a 99 dB speaker needs 100 watts to produce 119 dB, while an 84 dB speaker needs 3,162 watts to reach the same level. For system design, sensitivity determines amplifier requirements. The formula is: required power = 10^((target SPL - sensitivity - 10log(N))/10), where N is the number of speakers. SonaVyx's speaker measurement tool measures actual sensitivity using swept sine excitation and calibrated SPL readings.