- https://github.com/topisani/OTTO - An OP-1 inspired all-in-one synth/sequencer/sampler/recorder/more solution. The OTTO is a complete hardware and software solution, with synths, a sampler, effects, sequencers, and studio modules. It is heavily inspired by the OP-1, but takes some things in a different direction. The goal is to create an all-in-one portable device, that allows anyone to play around with electronic music. It shall be open and accessible, while maintaining the very constrained interfaces, necessary to really be creative.
The software is modular, with modules in six groups: Synths, drums, effects, modulation, sequencing, and studio. Each module has up to 4 settings, that can be controlled using 4 rotary encoders. Like the OP-1, the colours of the 4 rotaries corresponds to the colour of the option on screen that will be changed. Each module slot will be accessible from a single hardware button press. The software will be set up to run on a Raspberry Pi, with a small AMOLED screen, 4 rotary encoders, and around 20 buttons. This can then be built into any kind of enclosure, with or without a midi keyboard and other bells and whistles.
Digital Audio Workstation
- Linux Digital Audio and Music Workstation Comparison Matrix - collaborative Google Spreadsheet
- Ardour - a professional tool for working with audio and MIDI.
- harvid - HTTP Ardour Video Daemon, decodes still images from movie files and serves them via HTTP.
- https://github.com/onkelDead/ardmix - Android app to control Ardour via OSC for live mixing and recording
- https://github.com/jean-emmanuel/ardour-control - OSC Control Surface for Ardour. Based on Len Ovens' control surface.
- ArdouVy - a remote controller for the Ardour Digital Audio Workstation, that supports basic DAW operations through OSC protocol. It has been developed with recording and rehearsing needs in mind, allowing the musician(s) to control the main recording and monitoring operations without the need to be next to the computer. Please note that this is still a beta and debug release, intended just for testing and still not complete. Don't yell at me, it's still a work in progress and, much more important, I'm a musician, not a programmer :)
- Qtractor - an Audio/MIDI multi-track sequencer application written in C++ with the Qt4 framework. Target platform is Linux, where the Jack Audio Connection Kit (JACK) for audio, and the Advanced Linux Sound Architecture (ALSA) for MIDI, are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio.
- YouTube: Why, Phil? - Yassin Philip's Free Open Source Studio
- REAPER - digital audio workstation software: a complete multitrack audio and MIDI recording, editing, processing, mixing, and mastering environment. Nagware. No LV2 support yet.
- https://github.com/justinfrankel/reaper-sdk - REAPER C/C++ extension SDK
- https://www.helgoboss.org/projects/playtime - clip launcher, Ableton-like, in a floating window. Windows/Mac only :'(
- YouTube: Playtime Plugin For REAPER Demo
- ReaPack - package manager for REAPER, the Digital Audio Workstation. Discover, install and keep up to date your REAPER resources including ReaScripts, JS effects, extensions, themes, language packs, templates, web interfaces and more.
- https://github.com/RobU23/ReaScripts - Lua scripts for REAPER
- https://github.com/ZoeB/harvest - The Harvest project is a collection of files that are useful to people using the Reaper DAW, such as preset lists and note maps.
SWS / S&M
- The SWS / S&M extension - a collection of features that seamlessly integrate into REAPER, the Digital Audio Workstation (DAW) software by Cockos, Inc. It is a collaborative and open source project. A bunch of actions: Filter REAPER's action list with "SWS"! The Snapshots window allows you to save selected track parameters for recall later. The Resources window is a versatile tool, but its main job is to let you fill your own "slots" of projects, track templates, FX chains, media files, etc. Just fill some slots and filter the action list with "Resources"! Groove tool is for quantizing audio and MIDI: learn a groove from an item and apply it to other items! Cycle Actions - Make special/advanced actions that perform sub-actions successively, or offer conditional statements, or etc. Marker actions allow you to place any action as a marker, and have that action ran when the play cursor crosses over that marker. Tempo manipulation and warp grid allows you to do extensive tempo manipulation and tempo mapping. If that's not enough, you can also freely warp grid using nothing but mouse. Anaylze and normalize loudness using the tools fully compliant with EBU R128 Loudness Recommendation. Power up your mouse usage with contextual toolbars. Show different toolbar at mouse cursor for each part of the interface. ReaConsole is a keyboard command interface for common track tasks. Notes window allows you to write custom notes for projects, tracks, etc but also for marker and regions. They can follow playback too (subtitles, lyrics, etc). Region playlist (non-linear play), Live Configs (for live performers: use REAPER like an FX pedal), additional zoom features, project management, color management, automatic colors/icons, LFO generator, cue buss generator, easily previewing and playing takes at mouse cursor, custom mouse cursors, etc.
- https://github.com/justinfrankel/super8 - An 8 channel, MIDI controlled synchronized audio looper for JSFX
- YouTube: Tutorial Videos - playlist, Leandro Facchinetti
- https://github.com/noedigcode/gidPatches-for-Reaper - Switch between different patches for live keyboard playing using Reaper.
- LMMS - a free cross-platform software which allows you to produce music with your computer. This covers creating melodies and beats, synthesizing and mixing sounds and arranging samples. You can have fun with your MIDI keyboard and much more – all in a user-friendly and modern interface. Furthermore LMMS comes with many ready-to-use instrument and effect plugins, presets and samples.
No LV2 support. 
- LMMS Sharing Platform - Share your work with the LMMS community.
- Zrythm - a free GNU/Linux music production system (DAW) focused on electronic music and high modularity. built using C and the GTK+3 toolkit and borrows ideas, concepts and code from other projects such as Ardour, Jalv, Bitwig and Cubase. It is built with the intention to provide GNU/Linux users a full-featured alternative to proprietary DAWs and offers a unique approach to workflow that other GNU/Linux DAWs lack.
- Non - powerful enough to form a complete studio, fast and light enough to run on low-end hardware like the eeePC or Raspberry Pi, and so responsive and reliable that it can be used live, the Non DAW Studio is a modular system composed of four main parts: Non Timeline, a non-destructive, non-linear audio recorder and arranger. Non Mixer, a live mixer with effects plugin hosting and advanced Ambisonics spatialization control. Non Sequencer, a live, pattern based MIDI sequencer, and finally, the Non Session Manager to tie together these applications and more into cohesive song-level units.
Non-intuitive - e.g. one has to manually type in other Non application commands to link them to a track session.
Menus close when you click on them, argh.
On start, must create an actual project (Project/New) to add tracks.
No GUI item to import audio files, must be dragged into track list.
Doesn't auto switch tracks to stereo mode when stereo wav is imported.
No master track, must be created and routed manually.
Channel strips needs to be manually (and externally) routed with other Non apps.....
- MusE - a MIDI/Audio sequencer with recording and editing capabilities written originally by Werner Schweer now developed and maintained by the MusE development team. MusE aims to be a complete multitrack virtual studio for Linux, it is published under the GNU General Public License.
To use a softsynth:
- MusE Settings menu
- Midi Ports / Soft Synth
- Add synth instance
- Switch midi send on track to synth instance
- T7 - a multi award winning workstation, featuring powerful and creative tools to inspire the modern musician. Unlike typical ‘Lite’ versions, we do not impose any restrictions – you get unlimited track count, powerful features, compatibility with all popular plugins and efficient performance on Mac, Windows and Linux operating systems. Only available as part of our OEM partner sales programs.
- T6 DAW - freeware, features an intuitive, single-screen interface. Input, waveform and mixer – including EQ, level, pan and plugins – are laid out from left-to-right. Simply drag-and-drop additional features and automation on any track as needed. Unlimited numbers of audio and MIDI tracks, combined with a professional feature set, allow you to compose, record, edit, mix and share your music with ease. Modest CPU requirements make T6 ideal for use on nearly any Mac, Windows or Linux computer.
- Rosegarden - a well-rounded audio and MIDI sequencer, score editor, and general-purpose music composition and editing environment.
No lv2 support. 
Open Octave Midi
- OOMIDI - a fork of Rosegarden/MusE (??) 1.7.3, concentrating on Midi matrix, event, and matrix percussion editing, and the development of keystroke and mouse based workflow with Jackmidi intended as it's port device base for predominately orchestral composers and writers.
Libre Octave Studio
- Libre Octave Studio - LOS, open source MIDI/Audio sequencer. LOS is developed from the base code of OOM2 (OpenOctaveMidi2) and MusE (Muse Sequencer) written by Werner Schweer.
- Traverso DAW - an audio recording and editing program which is very well suited to record a single voice, a band, an ensemble, a whole orchestra or any other source of music!
Slow development, minimal website.
- LNX_Studio - a Digital Audio Work Station for Mac and Linux created in the SuperCollider language. It has a powerful set of tools for creating music, all of which can be networked. Co-location gigs or real-time collaborations don't have to be in the same room.
- Frinika - a free, complete music workstation software for Linux, Windows, Mac OSX and other operating systems running Java. It features sequencer, soft-synths, realtime effects and audio recording.
Java, interface can be somewhat janky..
- MusiKernel - an all-in-one DAW and suite of instrument & effect plugins, designed to be easy to install and use without the need for any 3rd party software. Simply install the package for your operating system, select your audio and MIDI hardware, and start making music.
Pros: Quick to use, nice conception of a DAW.
Mids: Can only use own plugins, makes it fast.
Cons: UI could do with some polishing.
- send volume control
- when renaming, keep item name border even when mouse not over, pressing enter finishes renaming
- when copying an item, ctrl-v to paste it in the original track
- when drawing a sequencer item, click drag release for length
- when adding a sequencer sound item, highlight the beat it will be added at
- ctrl mousewheel up and down for horizontal zoom in and out
- note length?
- click track/metronome
- double click on stop = panic
- ray-v - noise generator
- Genesis - a work-in-progress digital audio workstation with some ambitious goals: peer-to-peer multiplayer editing, complete plugin safety, and a built-in peer-to-peer community which shares plugins, projects, and samples.
- noisicaä - an open source DAW for GNU/Linux built around the idea of a modular synthesizer.The project is currently in pre-alpha state. You can try it out, but it is not recommended to use it for anything serious.
- https://github.com/DBraun/DawDreamer - an audio-processing Python framework supporting core DAW features such as audio playback, VST MIDI instruments, and VST effects. DawDreamer is written with JUCE, with a user-friendly Python interface thanks to pybind11. DawDreamer draws from an earlier VSTi audio "renderer", RenderMan.
- Audiotool - web service, a powerful online music production studio right in your browser. All crafted with lots of love for the small details. All your tracks, samples and presets are stored on the Audiotool servers and are accessible from any browser. Publish your finished track straight from the app to the Audiotool website, SoundCloud, Youtube or Facebook.
- AudioSauna - transforms your web browser into a fast and flexible music production studio with built in synthesizers and live effects.
- GridSound - a (work-in-progress) free HTML5 DAW (Digital Audio Workstation) based on the new Web Audio API.
Windows / Mac
- KRISTAL Audio Engine - a powerful multi-track recorder, audio sequencer and mixer - ideal for anyone wanting to get started with recording, mixing and mastering digital audio. It is designed as a modular system. The main application provides a mixing console, while the audio sequencer, live audio input and so on are loaded as separate Plug-Ins. Windows.
- DarkWave Studio - a free Digital Audio Workstation for Windows. Featuring a modular Virtual Studio, Pattern Editor, Sequence Editor and Multitrack Hard Disk Recorder. It has support for VST/VSTi instrument and effect plugins.The virtual studio has a modular design allowing machines to be connected in an ad-hoc fashion. The pattern editor enables the quick creation and modification of patterns by clicking to add or delete notes and dragging notes to move or resize them. The sequence editor allows you to queue patterns to play for each control track in any arrangement, enabling reuse of patterns and quickly remixing projects.The Multitrack Hard Disk Recorder allows you to record the output of any machine and record it to 16-bit Integer or 32-bit Floating Point PCM encoded .WAV files for full-quality post-production editing or for conversion to MP3/FLAC/etc.
- Podium Free - a freeware edition of Podium. It is fully functional with only a few feature limitations. Download and installation does not require registration.
- MuLab Inspiring Music Production Studio - an inspiring music studio for Mac OSX and Windows featuring an integrated top-quality modular synth and effect engine.MuLab is an easy and rock-solid tool designed to create, record, edit and finalize your music!
- MuLab 7 Docs: MuLab Versions - MuLab 7 can work in 2 modes: Free mode (MuLab Free) and unlimited mode (MuLab UL).Both MuLab modes are fully functional, but the difference is that when you cross one of the limits of MuLab Free, then you enter demo mode and you'll regularly hear a soft noise.
- Ohm Studio - the first real-time collaborative digital audio workstation. Start a project, invite musicians and make music together.
- Free - Up to 10 projects
- Subscription - Up to 200 Projects... but unlimited until offline mode is available!
- https://github.com/Noahdw/Strauss - A Qt based DAW for windows
- http://www.bitwig.com/en/bitwig-studio - $, good! includes clip launcher like Ableton. in-built modular synthesis system.
- https://github.com/davem2/sfz2bitwig - Converts sfz instruments into Bitwig Studio multisample instruments. The Bitwig multisample format is more basic than sfz. Features that are unique to sfz will be lost in the conversion process.
- Waveform - a rapidly evolving application specifically designed for the needs of modern music producers. Specializing in creative and inspirational workflows and avoiding features not explicitly needed allow the app to remain surprisingly fun and intuitive. While other apps try to appeal to broad user groups, for example film score, live sound, performance – we are laser focused on music production.
- Organizing Clips into Scenes in Ableton Live - non-Linux
- What's this Ableton thing everyone keeps talking about? - YouTube - Benn Jordan, aka The Flashbulb
- https://github.com/carrierdown/mutateful - Add-on for Ableton Live that enables live coding functionality fully integrated into Live's session view.
- Native Instruments: Maschine 2.0
- Splice - Unlimited backup, version control & private collaboration for Ableton Live, FL Studio, Logix Pro X, GarageBand. - $
- zenAud.io ALK - a cross between a sequencer and a looper. Like a traditional looper, clips are performed live and subsequently looped to create layers of sound. Like in a sequencer, the loops can be drawn, moved, copied, cut and pasted in a musical arrangement. When it’s time to perform the song, ALK will follow your arrangement, pressing the necessary virtual pedals to arm channels, trigger effects, and record and play loops at the right time. Freeing you to do what you do best: perform. zenAud.io ALK runs on macOS Yosemite or higher. - $
Based on Ardour.
- n-Track 8 - A recording studio in your computer. Studio quality recording, editing and mixing software. n-Track Studio brings you professional audio quality and easy workflow.
Windows/Mac - $
- Usine - the ultimate Digital Audio Workstation made for live or studio. Usine Pro is designed as a flexible software solution for spontaneous electronic music creation, including live sampling, effect processing, and sound design. Usine can to host VSTs/AU, process and route audio or midi, and design personalized virtual control interfaces. - $
- Cantabile - Play VSTs, trigger media clips, instantly switch between songs, integrate with your existing hardware, control it all via MIDI and simply perform better. - $
- MuLab - an inspiring music studio for Mac OSX and Windows featuring an integrated top-quality modular synth and effect engine. MuLab is an easy and rock-solid tool designed to create, record, edit and finalize your music. - $
- Geist is a next-generation sampling drum machine designed to create evolved beats and grooves, freeing you from the limits of pre-packaged loops and over-complicated DAWs. VST or stand-alone. - $
- https://github.com/zamaudio/ptformat - reads and parses ProTools session files.Audio and MIDI source/region/track information is extracted, as well as MIDI note events.The idea is to make ardour open PT sessions.
- https://github.com/mntmn/produce - a new, minimal linux DAW (mainly a sequencer) for hackers. scalable vector UI based on the GLV toolkit. minilisp as scripting language / project file format and for keybindings. connects via JACK MIDI to synths and audio hardware. connects via multiple JACK Audio outputs to plugin racks for mixing.
Last commit 2015, buggy
- PROTUX Digital Media Workstation - being developed to be a complete Digital Media Production tool, or Digital Media Workstation. We focus on develop it for GNU/Linux users, but it runs in any workstation with a Java >=1.5 VM installed, and even in the web thru a standard browser that supports Java (Believe or not). Protux aims to offer an integrated environment for audio, video and midi production, thru a inovative interface where the productivity is focused.
Last development was in 2009.
- Wired aims to be a professional music production and creation software running on the Linux operating system. It brings musicians a complete studio environment to compose and record music without requiring expensive hardware.
Last development was in 2009.
- http://ayyi.org - There is currently one main gui application using Ayyi, AyyiGtk, which aims to be a conventional audio/midi sequencer. Ayyi is a Linux libardour based modular audio production system.
Modular synth tracker/sequencer
- Beast - a music composition and modular synthesis application released as free software under the GNU LGPL, that runs under Unix. It supports a wide range of standards in the field, such as MIDI, WAV/AIFF/MP3/OggVorbis/etc audio files and LADSPA modules. It allows for multitrack editing, unlimited undo/redo support, real-time synthesis support, 32bit audio rendering, full duplex support, multiprocessor support, conditional MMX/SSE utilisation for plugins, precise timing down to sample granularity, on demand and partial loading of wave files, on the fly decoding, stereo mixing, FFT scopes, MIDI automation and full scriptability in scheme.
Does any other software have channel strip sequencing, piano roll, tracker, modular processing and mixer? Interface still needs work.
Requires the https://github.com/tim-janik/rapicorn GUI library to build.
Need to figure out how to get LDFLAGS='-llibpng12.a' (older libpng) to work properly.
- Radium - a music editor with a new type of interface - Tracker-like but with waveforms instead of hex codes). Compared to the normal sequencer interface editing is quicker and more musical data fits on the screen. However, despite its unusual appearance, it's a design goal for Radium to be straightforward to use, and easy to learn. It should not be harder to learn Radium than any tracker or most midi sequencers. 
- YouTube: Radium 3.6.6 playing the demo song
- YouTube: RADIUM - Tree of bugs song
- SunVox - a small, fast and powerful modular synthesizer with pattern-based sequencer (tracker). It is a tool for those people who like to compose music wherever they are, whenever they wish. On any device. SunVox is available for Windows, Mac OS X, Linux, Maemo, Meego, Raspberry Pi, Windows Mobile (WindowsCE), PalmOS, iOS and Android. Closed source, Android $.
Niiiiiice. Buzz-like modular synth with tracker style sequencing. No traditional piano roll.
- https://github.com/warmplace/sunvox - Community-maintained mirror of SunVox distribution
- https://github.com/warmplace/sunvox_sources - Community-maintained mirror of source code for earlier versions of SunDog and SunVox Engine
- YouTube: Chiptune Music with SunVox - Tutorial - playlist by HOOU HfMT
- YouTube: SunVox Tutorials, Tips, and Tricks - playlist by Solar Lune
- YouTube: SunVox - playlist by easy and nice waki
- YouTube: SunVox Tutorials - YouTube - playlist by Daedalus Young, mostly on transcribing
- YouTube: Learning SunVox - playlists by Game Jam!
- Radiant Voices - provides tools to create, read, modify, and write SunVox files. This includes project files ending in .sunvox, and module/synth files ending in .sunsynth.
- Solar Flares - Sound design and performance tools for SunVox.
- Buzztrax - a free software project to create a clone of the Buzz music composer. The driving motivation is to preserve the playability of the compositions made with Buzz. Aims to be a music studio that allows one to compose songs using only a computer with a soundcard. If you’ve used tracker programs like FastTracker, Impulse Tracker, or the original AMIGA SoundTracker, that will give you an idea of how one can sequence music in Buzztrax. The Buzztrax editor uses a similar concept, where a song consists of a sequence with tracks and in each track one uses patterns with events (musical notes and control changes). In contrast to other Tracker programs, tracks are not simply sample players: a user can make a song using an arrangment of virtual audio plugins that are linked together to create different effects. Each of these machines can be controlled realtime or via patterns in the sequencer.
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH export MANPATH=$MANPATH:/usr/local/share/man export DEVHELP_SEARCH_PATH=$DEVHELP_SEARCH_PATH:/usr/local/share/gtk-doc/html export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig export GST_PLUGIN_PATH_1_0=$GST_PLUGIN_PATH:/usr/local/lib/gstreamer-1.0 export XDG_DATA_DIRS=$XDG_DATA_DIRS:/usr/local/share export GI_TYPELIB_PATH=$GI_TYPELIB_PATH:/usr/local/lib/girepository
Aldrin Modular Sequencer
- Aldrin - an open source modular music sequencer/tracker for the GNU/Linux operating system. It features a flexible audio routing system commonly found in expensive audio software, enabling you to mix, split, mutilate and modify audio signals emitted by software synthesizers and samples.
Dead, forked to Neil Sequencer
- Neil is an open source application for making music on Linux. It is a kind of music software known as a tracker. It is similar to the famous buzz for Windows. Neil was forked off Aldrin project because it was not being developed smoothly enough and, since Aldrin was the only Linux application I could actually make music on, I wanted to secure it from being made unusable (for me at least, so no offense to original developers - you did a great job).
- https://bitbucket.org/bucket_brigade/neil/overview - mercurial (hg). last updated 2013.
- Zupiter Alpha - a synthesizer and step-sequencer that runs in a browser, meaning you don't even need to download and install any software to use it. Its interface is designed to be minimalistic and simple, so as not to put off beginners. The sharing feature gives you the ability to instantly put your work online. 
- Buzz - the first ever "easy to use" free modular software based synthesizer. What this means is that the entire system is based on objects, which may be routed in a modular fashion, giving you the freedom to be as creative as you want. For example, if you wish to run 3 Physical Modelling synths and a Drum Machine through 2 seperate Stereo Delays, into a Mixer, through a Compressor and Parameteric EQ, and finally out to your speakers - no problem. Lay down your synths, connect the wires and you're done.
- Buzé - 100% pattern-based sequencer with envelopes and pianorolls. Supports a wide range of plugins for generating and processing audio, MIDI, value and note signals. 30+ built-in plugins. Supports VST, Buzz, Psycle, LADSPA and Lunar plugins natively
Imports ARMZ, BMX, IT, S3M, MOD, MID, SID song file formats. Wavetable can import WAV, MP3, FLAC, IFF and many more file formats. Features a basic wave editor. Full undo/redo, scripting support, configurable keyboard shortcuts and window layouts. Windows.