bass amp has a gain control but also has a input sensitivity switch wtf?

[bassman619]

Amp is memphis mc1.1500 ..this is something I dnt understand here. It has a gain control as all amps do but there is also a switch that slides back and forth that says input sensitivity. Left side says 1x. Right side says 10x. Can some one explain to me what does it control and where should I have it set? My settings on amp are as follows. Lpf_80hz ..gain 0.7v which results in pulse of 28-40volts outputting from the speaker wire connections. Which is making 1200-1500watts rms..Subsonic set at 37hz..bass boost 1/3 ..enclosure is tuned to 38hz. Head unit bass curve set at 80hz..so whats up with the input sensitivity switch?