Audiobahn Haters!

well guys im sorry if i pissed you off, it wasn't my intention. if i could, id change the name of the topic to audiobahn lovers!

A couple of things.  The bass boost is a gain, for one.  If you set the amp gain and get it just right with the deck voltage input.....then boost the bass, you have in fact increased the amp gain and you throw everything out of whack.  Generally could lead to clipping and failure of the sub down the line.  Another thing is, to boost the bass at whatever freq curve the amp might have (say 60 Hz), is to say "I have really set up a crappy sounding system, the frequency curve of the sub is missing sound in the 60 Hz range, and I need to boost it up to get the curve right".

In reality, you rarely have a deficiency of sound in the bass boost freq range.  The deficiencies are usually somewhere else, if they are there at all.  The control is there as a throwback to the originally ill-conceived "loud" button on OEM decks and home amplifiers, which boosted lows and highs to compensate for low volume.  It sounded like crap then and still does today. 

The best thing to have is a sub controller in the cabin, as a lot of manufacturers provide now.  Those only attenuate the bass, they don't boost it.

Don't worry about breaking them in.  If the sub maker required it, they would tell you in the manual.  Just use common sense with a new system, or with any new components of that system.  Start off on the easy side of loud, until such a time that you determine that everything is as it should be.

What you said above---- you erred by not setting gain right from the start.  A critical part of the installation.  Set gain to match input voltage, by meter is best but most people do it by ear.  Try to get it right, and a lot of amps have voltage markings around the gain so you can pinpoint the input a little better (you also have to know what the deck puts out).  You should leave the bass boost off at this time.  Once you have the system up and running, play it for several hours, using different music sources and different types.  Then you can tweak the gain to clean out any distortion that makes its way into the sound.  Then, only if you have determined that it sucks for sound, turn on the bass boost and say to hell with it!  No, j/k, leave the damn thing off.