I am wondering if some one can help me with input sensitivity. I have a phoenix gold xs2500 amp that has a bass gain from 0 to 18dB and an input sensitivity dial from .1Vrms to 3Vrms. My head unit's pre amp signal to the amp is at 5V. I have two questions. First, how would you calculate about what the input sensitivity dial should be set to. Is the idea simply to match the input sensitivity to the head unit, which would mean that the fact that my amp only goes as far as 3Vrms then it will always be 2V short of what it should be, or are there other calculations involved and it's not that simple. Second what is the difference between the bass and input sensitivity dial. I understand the concept behind input sensitivity and how it controls how sensitive the amp is to the preamp signal. The higher the preamp signal voltage the less sensitive to the input signal the amp should be to achieve the same power output. But how does the bass boost dial interact with the signal differently than the input sensitivity dial. Thanks for any help.