Speaker Sensitivity
Definition
Speaker Sensitivity
Speaker sensitivity is the sound pressure level produced by a loudspeaker at a distance of 1 meter when driven by 1 watt of input power (or equivalently, 2.83 volts into an 8-ohm load). Measured per IEC 60268-5, sensitivity typically ranges from 85 dB (low) to 110 dB (high efficiency horn). SonaVyx measures speaker sensitivity from calibrated SPL and known drive levels.
Sensitivity = SPL at 1m / 1W (dB), typically 85-110 dB for professional speakers
How It Is Measured
Speaker sensitivity is measured by driving the speaker with 2.83 Vrms (1 watt into 8 ohms) and measuring SPL at 1 meter on-axis. The measurement should be made in a free-field environment or using half-space measurement on a large baffle. SonaVyx measures the SPL level at a calibrated distance and can calculate sensitivity when the input power is known, providing a quick field check against the manufacturer specification.
Practical Example
A PA speaker is rated at 99 dB sensitivity. At 1 watt (2.83V) and 1 meter, SonaVyx measures 97 dB — within the typical ±2 dB tolerance. With 500 watts of power (27 dB above 1W), the maximum output is 99 + 27 = 126 dB at 1 meter. At 20 meters (26 dB inverse square law loss), the maximum level is 100 dB SPL — sufficient for a 200-seat venue.
Sensitivity vs Efficiency
Sensitivity (dB SPL at 1W/1m) and efficiency (percentage of electrical power converted to acoustic power) are related but different metrics. A typical speaker converts only 1 to 5% of electrical power to sound. Horn-loaded speakers achieve higher efficiency (5 to 25%) due to better impedance matching between the driver and air. Higher sensitivity means less amplifier power is needed for the same SPL, reducing cost and heat.
Impact on System Design
Every 3 dB increase in sensitivity halves the amplifier power required for a given SPL. A speaker with 99 dB sensitivity needs only 125 watts to reach 120 dB at 1 meter, while a 90 dB sensitivity speaker needs 1000 watts. For large-scale PA systems covering thousands of seats, high-sensitivity speakers dramatically reduce the amplifier rack size, power consumption, and cost.
Bandwidth Considerations
Manufacturers sometimes specify sensitivity as an average across a limited bandwidth. A subwoofer rated at 100 dB sensitivity might only achieve that level from 60 to 200 Hz, with significantly lower output at the frequency extremes. SonaVyx measures the actual frequency response at the measurement distance, revealing the true sensitivity across the full bandwidth rather than just the specification number.
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