There is one failsafe protection circuit built into every car audio system, the space between one’s ears. A functioning brain in conjunction with what scientists have now termed as “common sense”, seems to be a remarkably powerful tool for humankind. Those who have made this vital connection seem to have great amounts of fun with little or no negative economic setbacks.
The common sense lobe of the brain does require some raw data in which to start deriving the given odds in a particular circumstance. This particular lobe of the brain is capable of advance learning functions from direct field experience. The pertinent data as it relates to vehicular audio systems is the assessment of distortion levels and how they relate to peak energy levels, and the subsequently related issue of said sustained distorted energy level.
This means that your audio system is capable of play to a certain level of clean SPL. The headunit is running clean, the amplifier is making nice clean power, the subs are free of distortion and the electrical system is supplying the amp(s) with necessary current. In this state, the system can play both loud and smoothly safe. Now, when you crank the gain a bit more, the sound starts to get grainy, edgy and no longer smooth. This is bad.
This tiny increase in spl comes at a horrific price. The heat generated in the system goes up exponentially. The excursion doubles as the amp(s) lose all damping and the suspension stretches beyond capability. Something is going to break.
Take the time to learn the systems limits, know how hard the different parts of the system can be pushed, for how long before they really heat up and when excursion goes out of control. We advise serious users who want to push things to the limit to learn how to measure their amp power and enclosure impedance.