1 picowatt Sound Power = 0dB Sound Power Level
1 W Sound Power = 120dB Sound Power Level
Sound Intensity = Sound Power / surface area
Half space surface area = 2πr2
dB Sound Intensity Level = dB Sound Pressure Level
dB SPL of 1 Watt Sound Power at 1 meter into half space = 10 log (1 W / 2π meter2) = 120dB SWL - 10 log (2π) = 112dB SPL
Efficiency = (Power output / Power input) * 100%
112dB SPL at 1 W at 1 m sensitivity = 100% efficiency
102dB SPL at 1 W at 1 m sensitivity = 10% efficiency
99dB SPL at 1 W at 1 m sensitivity = 5% efficiency
92dB SPL at 1 W at 1 m sensitivity = 1% efficiency
89dB SPL at 1 W at 1 m sensitivity = 0.5% efficiency
82dB SPL at 1W at 1m sensitivity = 0.1% efficiency
2.83 V = √(1 W * 8 Ω)
Audiophile Heretic, July 14, 2026 Menu