If you're setting up your competition car, your amplifier gain settings will probably be a little more conservative. The reason for this is simple: you don't need a whole lot of volume for a typical sound quality competition. In IASCA, the loudest track played during judging is sound linearity, and it only needs about 105 decibels of clean output to pass the test. This is fairly loud, but not anywhere near the maximum capability of most quality systems.
So why not just set the amp gains high and leave the volume on the head unit lower? The reason is noise. IASCA can take a maximum of 25 points for sound system noise, some of which can be avoided by having the amp gains set only to the necessary amount and no higher. The noise judging is performed with the head unit at its maximum volume, so any extra amp gain will create hiss in the system. Just be sure to turn up the gain on the sub amp for the SPL portion of the judging so that you will also score well in that category.
When your gain structure is set properly, the noise and distortion disappear, leaving nothing but pure music.
That's all for this month; as always, e-mail your questions to sbrown@alpine-usa.com, and I'll see you in the lanes.