Audio Processing U

Audio Processing University – Lessons for your ears!

We audio processing mainiacs refer to all kinds of “distortion” that only we seem to be able to hear.   You will hear us toss around all kinds of wierd terms to describe these seemingly mythical sounds we hear when evaluating audio processing systems.

This page is designed to give you an audio class for your ears, because it is all about how to listen for these sounds.

Listening to these files will also help you with some of the audio concepts described in my Audio Processing 101 page .

We’ve taken a small piece of audio from Joan Armatrading’s song “Lover’s Speak” to use for today’s lesson.  I will use grossly exaggerated audio to show what we are hearing when we use terms such as “harmonic Distortion”, “Pumping”, etc.

(when your browser asks what to do with the files below, just save it to your disk for playback)

Our first audio clip demonstrates our sample song as it is supposed to be heard.

Normal Audio
This next clip demonstrates harmonic Distortion

Harmonic Distortion Demonstration


We are now up to an audio clip which demonstrates “Intermod Distortion”.  Notice how the piano and vocal audio in this clip sounds “jagged” due to bass note activity.

Intermod Distortion Demonstration


This last clip demonstrates the phenomenon known as “pumping” notice how piano and voice “jump down” in level when the kick drum hits….

Pumping Demonstration

Hope this helps!


C. Gould



Audio Clip used in the demonstration – Joan Armatrading – “Lovers Speak” from the album “Lover’s Speak” (c) 2003 by Denon Records.