Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems.
Audacity is free software, developed by a group of volunteers and distributed under the GNU General Public License (GPL). Programs like Audacity are also called open source software, because their source code is available for anyone to study or use.
PC based Oscilloscope and Spectrum analyzer using sound card
AUDio MEasurement System - a multi-platfrom system for audio measurement through sound card in the PC. It contains: generator, oscilloscope, audio spectrum analyzer (FFT) and frequency sweep plot. Compiles and works under Linux, Windows and MacOS. Source code is available in "git" and as ZIP snapshot. For more information see README.md
LAoE is a rich featured graphical audiosample-editor, based on multi-layers, floating-point samples, volume-masks, variable selection-intensity, and many plugins suitable to manipulate sound, such as filtering, retouching, resampling...