ESynth is a free program designed to explain the harmonic analysis and synthesis of signals. With ESynth you can create signals by adding together individual sinusoidal waveforms (sinewaves) and study the resulting waveform and spectrum. You can also perform an analysis of an input waveform, to see how a given sound can be represented in terms of a sum of sinewaves. More information.
BROWSE - Simple tool for browsing audio files
BROWSE is a program for browsing audio recordings. With BROWSE you can drag and drop audio files in a range of formats onto the display to see and hear their contents. BROWSE allows you to zoom, scroll and save the audio files to other formats. More information.