Free Tool
dB, Watts & Unit Converter.
The quick conversions you reach for on site, power ratios in dB, SPL change with power and distance, and metres to feet.
Free to useNo loginMade by working AV crew
Power ratio to dB
SPL change with power / distance
Length
Power ratio in dB = 10 x log10(B/A). Doubling power = +3 dB. Doubling distance = minus 6 dB (free field). Voltage or SPL doubling = +6 dB.
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