How do I calculate the power required for my amplifier?
Power requirements depend on speaker sensitivity, desired SPL, listening distance, and headroom. Use P = 10^((SPL - Sensitivity + 20*log10(Distance))/10) to calculate basic power, then add headroom for dynamic peaks. See also our kWh to Watts Calculator.
What is the difference between RMS, peak, and peak-to-peak voltage?
RMS voltage is the effective voltage that delivers equivalent power as DC. Peak voltage is √2 times RMS (1.414x), while peak-to-peak is twice the peak voltage (2.828x RMS).
How much headroom should I allow in my amplifier?
Typical headroom ranges from 3-6 dB for most applications. Classical music may need 10-20 dB headroom for dynamic peaks, while compressed music needs less. Each 3 dB requires double the power.
Why does speaker impedance affect amplifier power output?
Most amplifiers are voltage-limited rather than power-limited. Lower impedance loads draw more current for the same voltage, increasing power output. Halving impedance typically doubles power output.
How does distance affect the power requirements?
Sound follows the inverse square law - doubling distance reduces SPL by 6 dB. This means you need 4 times more power to maintain the same SPL at twice the distance.
What speaker sensitivity rating should I use?
Use the 1W/1M rating (typically given as dB SPL at 2.83V for 8Ω speakers). Higher sensitivity speakers (>90 dB) need less power, while lower sensitivity speakers (<85 dB) need more power for the same SPL.
Can I use this calculator for different speaker impedances?
Yes, the calculator works for any impedance from 2Ω to 32Ω. Remember that most amplifiers produce different power levels into different impedances, and some may not be stable into very low impedances.