GNU Octave; digital audio signal; frequency masking; time masking;

We cannot imagine this world without digital audio. Every amateur can create digital audio on his own without a lot of effort. Listening to music in digital form is the most enhanced because we found out that digital audio is easy to use, share, create, manipulate and distribute. Digital audio techniques have become very useful in this time. There is wide range of audio processing techniques, such as filtering, compression, synthesis, de-noising and addition of sound effects. We would like to interpret the general principles and some of these techniques by using GNU Octave. We choose this tool because Octave is language primarily designed for solving numerical linear and non-linear problems, contains tools for digital audio processing and is also freeware widely used in research and teaching area.