GNUsound is a multitrack sound editor for GNOME 1 and 2.

midiscore chung is a small program for easy step by step compose record edit midi music song with optional quantize using a midi keyboard entering play chord and control with some piano keys and save / load from pc or export / import as midifile . a standalone freebasic program . enhanced realtime record adds sustain delay and velocity variation effect according to number of played notes (resonance) and can also enter notes with the pc keyboard . can load and even enhance existing midifiles . record autopause when nothing is played .
chungswebsite.blogspot.com/2019/05/midiscorechung-small-program-for-step.html
Advanced GTK+ Sequencer is intended to use for music composition. It features a piano roll, as well a synth, matrix editor, drum machine, soundfont2 player, mixer and an output panel.
It’s designed to be highly configurable, you may add effects to its effect chain, add or remove audio channels/pads.
You may set up a fully functional network of engines, therefore exists a link editor for linking audio lines.
In conjunction with ags you need a realtime kernel and alsa support. `ags` uses conditional locks to keep several threads in sync that’s why you need at least a preemptible kernel.
KXStudio is a collection of applications and plugins for Linux, Mac and Windows audio production. KXStudio also provides Debian and Ubuntu compatible repositories.
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.
Tapedeck is an audio editor for Linux with an alternative control interface. Instead of a mouse, keyboard, and screen, it uses the DJ board Hercules DJ Control Instinct, and a set of LED graph displays (not currently implemented, simulated with terminal graphics).
https://github.com/vanjac/tapedeck
The audio file editor, baptised ‘Eisenkraut’, came into existence (as a scaffold) during a project class on audio programming in Java at the SeaM in Weimar. It is distinguished by a number of traits which makes it particularly interesting in the field of computer music: There are no restrictions with regard to the number of channels in a file, and there is an OSC interface via which the functionality can be extended, for example using the SuperCollider language. Possible applications of such extensions are the transfer of marker information or the maintenance of meta data for segmented files, the algorithmic editing (cut/copy/paste) of files, or the addition of your own sound transformations or special decoders (e.g. an MS matrix).
Multitrack Web Audio editor and player with canvas waveform preview. Set cues, fades and shift multiple tracks in time. Record audio tracks or provide audio annotations. Export your mix to AudioBuffer or WAV! Inspired by Audacity, this project is written in ES2015 using the Web Audio API.
naomiaro.github.io/waveform-playlist/web-audio-editor
github.com/naomiaro/waveform-playlist
SoundTracker is a music tracking tool for Unix / X11 similar in design to the DOS program FastTracker and the Amiga legend ProTracker. Samples can be lined up on tracks and patterns which are then arranged to a song. Supported module formats are XM and MOD; the player code is the one from OpenCP. A basic sample recorder and editor is also included. SoundTracker is free (“open source”) software, licensed under the GNU GPL.