Buckle-meister said:
What?! Did I miss something here? We have just shown that the 4-ohm speakers will sound louder for the same voltage from the amp than an 8-ohm speaker. Why on earth is the amplifier suddenly required to double its output?
Regards
Because if the voltage stays the same then the current has doubled with the 4 ohm load. Thus the total power has increased by a factor of 2. Think of it like this:
If you have a hose, running water through it, it is a 1" hose and the pressure is 10psi.
Then you have a hose that is 2" with the same 10 psi, which is going to put out more water? The 2" hose.
The PSI hasn't changed so the only thing that is increased is the amount of water.
It's the same way with your speakers, the 8 ohm are the 1" hose and the 4 ohm represent the 2" hose. More water (current) flows through the 2" but the water pressure (voltage) is the same.