Car Stereos: amps, wattage output, 4 ohms

Question
are maximum wattage for amps usually in 2 or 4 ohms?

Answer
Hi Drew,

There's no simple way to answer that question.  Most amps broadcast their specifications as (maximum number of channels x highest wattage per channel).  So if an amp is capable of 2x200 @ 2ohm, it'll be advertised as a 400w amp.  Amps' highest wattage output are normally realised at their lowest stable impedance, so if an amp CAN do 2ohm, its wattage rating is probably measured in 2ohms aswell.

Justin