Start by setting the low pass filter to around 80hz. You may adjust it up or down a bit to blend in with your other speakers after listening for awhile. Most people will have it set between 60hz and 100hz.
The gain control is meant to match the input level of the amp to the output level of your head unit. Depending on what head unit and other processing you may be running, the setting will change. Check out the gain setting tutorial on this forum for info.
Ok, I think I've got the settings where I want them, but need some clarification on the 'input level' on this amp. I am using a Panasonic CQ-C9801W, so I am unsure where the gain needs to be set.
Or is this setting just based on what sounds 'right'?