Manually adjusting amplitude of audio

I am trying to distort an audio file. How can I adjust the amplitude of the waveform so that the peaks are all maximized to a predetermined value? The idea is to be able to manipulate the amplitude level and thus manipulate the level of distortion. I am using a .wav file.

This is the effect I am looking for: http://en.wikipedia.org/wiki/Distortion#mediaviewer/File:Distortion_waveform.svg

Answer 1

[Anathea Pepperl]

I'm assuming that you are using a .wav file. First you will want to use wavread to read the audio data into Matlab. Then you could use logical indexing, like audio_data(audio_data > thresh) = max_value; in order to force values above a certain value.

You could also find peaks by finding where the derivative is 0 (use the second derivative to find if that value is a min or a max), and set the local maxima to your predetermined value.

Hope this helps!