Originally Posted by illusion

It does matter if you want to get nitpicky. As I stated above "the less impedance the more distortion", FETs are MORE efficient at higher impedance. You put more stress on an an amp with lower impedance and more stress = more distortion. Generally for subs and for most car audio it doesn't matter, there is enough noise in the environment to make the difference in THD inaudible. Many IASCA SQ competitors choose higher impedance for a truer signal reproduction. There's a reason many home audio systems are still 8 ohm(even though many high end home audio amps can handle as low as a 2 ohm load). The distortion will be more noticeable at lower volumes as the higher the output signal the smaller the percentage of THD is to the signal, in other words the SNR is lower at higher power. Also a PA(Power Amp, FET or whichever you'd like to call it) is MORE efficient at higher impedance, efficiency is a term to describe the amount of wasted energy in a circuit, NOT the amount of power it puts out.