To process audio signals that have come straight from the microphone would not be a good idea either, as the signal is barely a trickle of current. It would be like gathering a few scraps of heiroglyphs from an archealogical dig and trying to write a thesis on what the Egyptians thought of Barney the Dinosaur in ancient times. Erroneous sound signals are called noisy , because that's how they will sound. You can often hear this in badly tuned radios as static crackles or a quiet hiss in the background. This arises because your radio is not set up to receive all the audio information to give you a clear sound.
Distortion also damages sound signals.
This arises when the equipment producing the sound cannot adequately handle the sounds to give you a fair representation of what it is supposed to sound like. The most well-known example is probably of the Distorted Guitar, the kind of sound produced by heavy metal guitarists. That grungy, grating sound used in guitar solos is interesting, but I'm pretty sure that's not what a guitar actually sounds like. A twang on a guitar string produces a twang, not a Deep Purple power chord. That previous example also shows that Distortion and Noise are not always undesireable.