Impedance

Definition

Impedance is the AC load the amplifier sees. “8 Ω nominal” still dips; a 6 Ω bookshelf can look like 4 Ω in the bass. AVR wattage is usually specified two-channel into 8 Ω; 6 Ω numbers are higher current, not free headroom. If the speaker’s sensitivity is quoted per watt, compare the receiver rating at the speaker’s nominal load; if it is quoted at 2.83 V, compare the 8 Ω rating, because that figure already counts the extra power a lower impedance draws. Then check the minimum impedance in the manufacturer PDF.

Calculators that use this

• Amplification & power

  Amplifier Power Match (SPL) Calculator

  From speaker sensitivity, distance and target SPL, get required watts and whether a receiver can supply them with headroom.

• Amplification & power

  Speaker Wire Gauge (AWG) Distance Calculator

  Pick a minimum AWG so round-trip copper stays under 5% of the speaker impedance on your cable run.

• Amplification & power

  Ohm’s Law AV Rack Load Calculator

  Convert rack watts and wall voltage into amps and check the 80% continuous-load breaker rule.