Wayne Parham Messages: 18793 Registered: January 2001
Illuminati (33rd Degree)
There are a lot of reasons for distortion, so it is a topic that merits more in-depth discussion than just a generality. But I'll give a brief generality anyway:
Low level distortion is usually caused by things like noise, conversion errors in a digital system or zero-crossing in poorly designed amplifier somewhere in the signal chain. High level distortion is usually caused by overdriving something past its limits, usually voltage or current in an amplifier or mechanical limits in a speaker.