XAnalyser is a program to analyse a stereo audio signal. It has two displays:
- Frequency Spectrum
Using Fast Fourier Transform, the time domain of the signal is transformed into the frequency domain, i.e. the amplitude (in logarithmic scale) of the audio signal is plotted versus the frequency. Either the sum of the left and right channel of the audio signal can be shown or both channels simultaneously.
- XY Scope
Roughly speaking, the audio signal of left channel deflects a point horizontally and the right channel vertically (just as the beam of a CRT would do). Thus, an audio signal only present on the left channel produces a horizontal line, whereas an audio signal only present on the right channel produces a vertical line. A mono signal produces a 45 degree line. A stereo signal creates a wilde pattern (if the phase is correct, predominately in the same direction as a mono signal) or may even fill the entire scope.
XAnalyser supports the ALSA 1.0 and OSS sound devices.