dB
System
dB SPL @ 1 W / 1 m
Number of speakers
Load impedance
Max SPL
114.8 dB
Output voltage
15.49 Vrms
21.9 V peak
Output current
1.94 Arms
Power for +10 dB
300 W
sounds twice as loud
90 dB/W95 dB/W105 dB/W100 dB/W (yours)
1 W
100 dB
2 W
103 dB
5 W
107 dB
10 W
110 dB
50 W
117 dB
100 W
120 dB
Engineering Notes
How it works
A loudspeaker's sensitivity is the sound pressure it produces with 1 W input, measured at 1 m. Because human hearing (and decibels) are logarithmic, power and loudness are related in a surprising way:
SPL = Sensitivity + 10·log₁₀(P) − 20·log₁₀(d) + 10·log₁₀(N)
- Doubling the power adds only +3 dB, barely noticeable.
- Ten times the power adds +10 dB, perceived as roughly "twice as loud".
- Doubling the distance costs −6 dB (inverse-square law, free field).
- Doubling the number of speakers (same total power) adds about +3 dB of efficiency.
This is why a 5 W single-ended 2A3 amp driving 100 dB horns can fill a room, while a 40 W amp into 85 dB bookshelf speakers struggles. It also explains why a 50 W guitar amp is not that much quieter than a 100 W one. The output voltage is V = √(P·R).