A free multi-track audio editor and recorder
Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems. The interface is translated into many languages. The version currently hosted here is 2.1.0 (March 2015). More recent versions than this are available from http://www.audacityteam.org/download/ . 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. There are thousands of other free and open source programs, including the Firefox web browser, the LibreOffice or Apache OpenOffice office suites and entire Linux-based operating systems such as Ubuntu
A unified display of relevant technical and tag data for A/V files
MediaInfo is a convenient unified display of the most relevant technical and tag data for video and audio files.
Sound Editor for KDE
Kwave is a sound editor for the KDE environment. It is written with KDE/QT and is extendable through a powerful plugin interface. For the moment it supports .wav files and many other formats, recording/playback via PulseAudio, Qt Multimedia, OSS and ALSA and some simple effects
QtGain is a simply frontend for MP3Gain, VorbisGain, AACGain and Metaflac which analyses and adjusts your media files so that they have the same volume without the need to reencode the files. With QtGain you can simplify this job to replay gain your media files. Simply add your files or folders via drag & drop or select a folder with a file dialog. QtGain starts gaining immediately after adding some files and of course you can add more files while QtGain works on your files. Files which are already gained and need no recalculating are automatically skipped. Files which cannot processed are automatically listed in a dialog box at the end of the job.
FFT Spectra is a tool for visualization of frequency spectra of an audio signal. What is it good for? For instance, you can verify whether you are able to sing and whistle in-tune or tune your guitar.