Is 2 ohm stereo equal to 4 ohm mono or is 2 ohm mono equal to 4 ohm stereo?

Answer 1

The unit "ohm" is a measure of resistance, the quality of a component or circuit that impedes or holds back the flow of current. For example, a narrow garden hose would have more resistance to water flow than a fatter hose. The output impedance of an amplifier can be 2 ohms, 4 ohms, 8 ohms, or 16 ohms. And these numbers are not a basis of comparison for power output between two amplifiers stereo or otherwise. What is essential is that the input impedance of the speakers should match the output impedance of the amplifier. On the back of most speakers you will find a number, 2, 4, 8, 16 followed by the Greek letter omega, Ω. That's the input impedance of the speaker measured in ohms. A stereo amplifier has to have separate circuitry for left and right channels. The output impedance of an amplifier should be printed on the back of the unit.

Answer 2

2 ohm mono equal to 4 ohm stereo?

Answer 3

Your question is not clear. Are you referring to the bridging of a two-channel stereo amp to a single-channel mono amp? That will depend on the bridging circuit. If it is parallel bridging (most common), and the output impedance is 4 ohm in the stereo mode, it will be 2 ohms in the bridged (mono} mode.