It is better contrary to popular belief. Distortion its caused by the amp clipping because it cant keep up with the power demand. And distortion its the main cause of speaker failure.
Also Kenwood has always made shitty overrated amps :/
E:To answer the original question.

1)Turn the volume up on your radio without the amp turned on, and set the equalizer to the desired settings.
2)Set the radio to max volume, or at least the max volume you normally listen music at.
3)Adjust eq as necessary to avoid distortion
4)Turn on the amp and listen for distortion, if there is turn the gain knob down until you cant hear any distortion.
5)The eq settings and any other settings on the amp will vary depending on the box you have. So you will have to set them up by ear.

Doing the above steps will probably not make it sound any better but it will guarantee the longest life expectancy for your equipment.

This post was edited by hotdogski on Apr 7 2011 11:54pm

xD

Yeah pretty much, remember that distortion isnt very distinguishable when ur playing low frequencies so u have to listen closely.
Its an infrasonic filter most likely, id set it at 25 assuming u have a conventional box.

That would probably be your low pass/ high pass/ no filter switch.

Wait, is it a knob or a switch?

lol so what do you suppose a "low pass/ high pass" is?