Is my votlage correct for Gain setting with mutlimeter?
 

Is this what I should set Gain with multimeter?

JL Subwoofer : 500 x 1 = 22.37 voltage
Hertz Front speaker: 300 x 1 = 17.32 voltage
Hertz Rear speaker: 210 x 1 = 14.49 voltage

System description:
1) Phoenix Gold 1600.5 5 channel amplifier
Front/Rear Channel
RMS Power Output:
125w x 4 @4 ohm Stereo
200w x 4 @2 ohm Stereo
400w x 2 @4 ohm Bridged

Subwoofer Channel
RMS Power Output:
500w x 1 @4 ohm
800w x 1 @2 ohm

2) JL Subwoofer
10W3v3-4: 10-inch (250 mm) Subwoofer Driver, 4 ohm
Power Handling (RMS): 500W @ 4 ohm

3) Hertz Speakers:
Front speaker: Power = 300 @ 4 ohm
Rear speaker: Power = 210 @ 4 ohm

Ohm's Law Calculator
Ohms Law Calculator

Attach is how my wiring setting. I don't think there's a bridge.

The Amp gain setting has a clipping led indicator. They said I don't need to do like Power * Resistance