impedance confusion

[Accord Man]

Originally posted by GSteg
300 watts at 4ohm WILL be the same as 300 watts at 2ohm. the gains are no way changed. if they are, then why would JL even pu on a gain knob? what the amp does is the amp detects the ohm and regulates the rail voltage so the amp would have enough power to put out that much of watts at 1.5-4.0 ohm

Nope, on any of those JL amps, 300w @ 4ohms and 300 @ 2ohms will not sound the same.
2ndGenTeg's idea is right on the money.. its something like an auto-gain.. Like you said, it detects the impedance and sets the voltage (fully variable switching)..