I'm guessing the dual 2 ohms is the best? and I've been kind of confused about amps.
600 watts, 4-Channel Amplifier
RMS Power Output:
4 Ohms: 100 watts x 4 chan.
2 Ohms: 150 watts x 4 chan.
4 Ohms Bridged: 300 watts x 2 chan.
If it's a 600 watt amp...then why is there only a total of 400 watts when you use 4 channels with the 4 ohms, but when you use 2 ohms it adds up to 600?
And why if you were to bridge the channels it would add up to 600watts at 4 ohms when previously 4 channels at 4 ohms only added up to 400?
Most amps (not all, as there are some exceptions), output less power at 4 ohms then 2 ohms.
Per Ohm's law, higher resistance results in less power, since the power supply in an amplifier can only draw so much current from the vehicle's electrical system and is subject to inefficiencies (only a 50% increase in power with a 2 ohm load versus a 4 ohm load).
However, when you bridge a pair of channels with a 4 ohms load, the amplifier will output more power than it will at 4 channels with 4 ohms because the output voltage has increased to what it would be at 4 channels with 2 ohms.
100W at 4 Ohms:
SQRT(Watts*Ohms) = Output Voltage
...SQRT(100*4) = 20 Volts per channel
Volts / Ohms = AMPS
...20 / 4 = 5A per channel (4 channels = 20A total)
150W at 2 Ohms:
SQRT(Watts*Ohms) = Output Voltage
...SQRT(150*2) = 17.32 Volts per channel
Volts / Ohms = AMPS
...17.32 / 2 = 8.66A per channel (4 channels = 34.64A total)
300W at 4 ohms, Bridged:
Output Voltage = SQRT(Watts*Ohms)...SQRT(300*4) = 34.64 Volts per channel
Volts / Ohms = AMPS
...34.64 / 4 = 8.66A per channel (2 channels = 17.32A total)
See the similarity in Amperage between four channels at 2 ohms and two channels at 4 ohms bridged? Also note that the voltage is exactly double when the channels are bridged with a 4 ohm load present then with 2 ohms and 4 channels.
