What setting should my amp’s input sensitivity switch be set at?

I am hoping someone can help as I am not an engineering type. I have an integrated Vitus amp connected to a CD player via an rca cable. The amp has a sensitivity Vrms setting for each input. It has three settings <2, <4, and <8 vrms. Would anyone know what this should be set at? The lower the setting the louder it goes but I am sure there is more to it than that.

Thanks for any advice you can give.
A CDP has an output of 2 volts which is enough to drive your amp. If you find it is too loud just change the setting on the amp to a higher setting to lower the volume. That is a nice feature on that amp!
don vito is right. Leave the gun, take the canoli. Er, I mean use the one that sounds right.

The non-technical way to think of this is, you know how sometimes you have to turn the volume up (or down) a lot when going from one source to another? Vitus is simply giving you a way to make them more the same volume. Its a convenience feature.
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