An open-source cross-platform audible audiobook manager. With over 250 stars by github developers, OpenAudible is the trusted audio book content manager.

An open-source cross-platform audible audiobook manager. With over 250 stars by github developers, OpenAudible is the trusted audio book content manager.

MinimServer is a new UPnP AV music server with a number of innovative features that make it easier to organize and explore your music collection. If you have a network music player that supports the UPnP AV standards (see this page), you’ll get much more from your music collection if you’re using MinimServer as your music server software.
Lplex is a console application meant to provide a free, quick, and hopefully painless way to:
You’re already fully equipped for hi-res audio (up to 24-bit/96khz) if you have a typical dvd-player and digital amp, and lplex is a way to take advantage of this.
DeaDBeeF (as in 0xDEADBEEF) is a modular audio player for GNU/Linux, *BSD, OpenSolaris, macOS, and other UNIX-like systems.
DeaDBeeF lets you play variety of audio formats, convert between them, customize the UI almost any way you want, and use many additional plugins which can extend it even more.

deadbeef.sourceforge.net
deadbeef.sourceforge.net/download
deadbeef.sourceforge.io/plugins.html
play.google.com/store/apps/details?id=org.deadbeef.android
CUI ~ A faceted library browser plugin for Deadbeef. Columns-UI-like
github.com/VirInvictus/deadbeef-cui
github.com/topics/deadbeef
github.com/topics/deadbeef-plugin
en.wikipedia.org/wiki/DeaDBeeF
TAudioConverter is a audio converter and extractor. It can convert almost any audio format to aac, ac3, mp3, flac, wav, ogg, opus or mpc. SoX is used to apply effects such as normalization, volume change etc. It can also extract audio streams from video files and encode them. Video files with more than one audio stream is supported. It is possible to run up to 8 simultaneous processes to shorten encoding time.

ozok.users.sourceforge.net
Download
Source
Wiki
Hydrogen Audio Topic
Doom9 Topic
Spetralissime is a standalone Spectrum Analyzer application based on high precision band pass filter bank, more adapted to the human audition. Spectralissime gives a more consistent spectrum analysis and allows better understanding of any audio phenomena thanks to its constant precision, from 20 Hz to 20 kHz.

www.vb-audio.com/Spectralissime
voicemeeter.com/vb-audio-spectralissime-professional-high-definition-multiband-audio-analyzer
This tool is aimed at people migrating a music library from iTunes™ to Foobar2000, and allows you to keep the various statistics and dates that are saved by iTunes. It reads these fields from your iTunes Library XML, and writes them to the file tags that are expected by the import function of foo_playcount. You can transfer playlists too.
It’s time to ditch Skype and TeamSpeak. All-in-one voice and text chat for gamers that’s free, secure, and works on both your desktop and phone. Stop paying for TeamSpeak servers and hassling with Skype. Simplify your life.
A web based audio/video streaming (PHP) application and file manager allowing you to access your music & videos from anywhere, using almost any internet enabled device.
ampache.org
github.com/ampache
www.reddit.com/r/ampache
en.wikipedia.org/wiki/Ampache

Discogs Enhancer is a free, open source extension that adds extra features to both Discogs.com and Chrome.
You can block sellers, use a dark theme, see price comparisons, get feedback notifications, convert foreign currencies, search Discogs and other online record shops with any highlighted text, improve tracklist readability, customize lots of Marketplace aspects, and more!
Every feature is optional so you can choose only the features you want to use.
LilyPond is a music engraving program, devoted to producing the highest-quality sheet music possible. It brings the aesthetics of traditionally engraved music to computer printouts. LilyPond is free software and part of the GNU Project.

Frescobaldi is a free and open source LilyPond sheet music text editor.
ly2video is a Python script which converts music represented by a GNU LilyPond file into a video containing a horizontally scrolling music staff which is synchronized with a MIDI-generated audio rendering of the music.
It is also possible to synchronize the video of the scrolling music notation with a previously recorded audio track of the same music, such as a live performance, even when the audio uses tempo rubato or is not precisely metronomic.
www.weblily.net/weblily-app/Clickable-Notation-Reference.html