First, we'll define the term "clipping." This was done very well by my friend Perry Babin over at Basic Car Audio & Electronics, so instead of repeating what he's already said, I will provide you the link to his page on clipping. Please take the time to view the rest of his site at http://www.bcae1.com/ as well. This site is well worth your time. So, without further adieu, This is the definition of clipping:
"BCA&E: "Too Little Power"
In short, clipping is when the amplifier is unable to produce a clean sinusoidal waveform output, and instead produces a waveform with flat peaks, or in extreme conditions, square waveform output, which sends direct current to the speakers instead of the expected AC voltage, which in turn causes heat to build across the speakers' voice coils.
Causes for clipping in a car audio amplifier:
1. input sensitivity (gain) on the amplifier is set too high, which causes the line voltage from the head unit to over-drive the input stage of the amplifier.
2. Poor grounding of the amplifier, which causes inadequate current flow for the amplifier's power supply to produce the required power output.
3. Inadequate wire gauge (size) for the amount of current draw, and length of wire used for pos(+) and neg(-) power connections at the amplifiers.
4. The need for a larger alternator to supply the required current while the car engine is running, or more deep cycle batteries to do the same while the engine is off.
5. The possible additional need to upgrade the "big 3" connections in your car's engine bay.
6. Overheating of the amplifier itself, although this is very uncommon and usually indicates an installation or design flaw.
7. Over-equalization of the source signal before reaching the amplifier's input stage, which causes over-voltage in relation to the gain setting for the amplifier.
A common error in novice car audio installation is the tendancy for a person to compensate for a lack of amplifier power or overall desired volume by the audio system by cranking the gain setting on the amplifier all the way to maximum, using the gain like a volume knob. This is how people end up with problems like blown amplifiers, blown speakers, and feedback, distortion, alternator whine, and constant audible thumping from the subs even at low volume levels.
Take the time to set your amplifier gains properly and reap the benefits of a clean audio system as a result!
More on how to set the gain or input sensitivity on your amplifier:
BCA&E: How to properly set your gain with an oscilloscope
BCA&E: Amplifier Gain Controls
