IndexLoudspeakersSpeaker SPL at the Seat
Speaker SPL at the Seat
Sensitivity, power and distance turned into level at your listening position.
The green zone, above 105 dB, leaves room for the peaks of music played at an 85 dB average. Free-field estimate. A furnished room returns some energy, so real levels at the seat are typically 2 to 4 dB higher.
Input
As printed on the spec sheet: dB SPL at 1 m for 2.83 V.
How it works
Three terms
The level at your chair is the speaker's sensitivity, plus what the amplifier adds, minus what distance takes away:
- Sensitivity is quoted for 2.83 V, which is 1 W into 8 Ω but 2 W into 4 Ω. The term converts your amplifier's watts back to that voltage reference.
- Distance follows the inverse-square law: 6 dB lost each time it doubles.
- Two speakers playing unrelated signals add 3 dB. Centred, identical content adds up to 6 dB.
How much power is enough
Well-recorded music has peaks 15 to 20 dB above its average level. To listen at an average of 85 dB with clean peaks the system has to reach about 105 dB. Solving for power:
Every 3 dB of extra sensitivity halves the power required. That is why an 8 W valve amplifier is plenty for a 98 dB horn and hopeless with an 84 dB mini-monitor.