I have worked with a couple of Linux software synthesizers like Amsynth, ZynAddSubFX, and Yoshimi and they are really capable synthesizers in terms of creating many various sounds. But, one thing I always wondered is what is the way to record these sounds? Do I have to record them with a microphone? That just does not seem right. I have seen some options to forward their MIDI output to other software like LMMS, but it just gives the notes, not the sound (timbre).
Also, I have seen no option in these synthesizers to record the sound being played to an audio file.
So, how are standalone software synthesizers (excluding those that have become integrated in other software like LMMS or Ardour) recorded?

  • 1
    Well, if you can forward the MIDI output of these synthesizers to other software, why cannot you to redirect their audio output?
    – trolley813
    Nov 8, 2019 at 9:29
  • Microphone is definitely not needed, since you can simply feed the audio-out into the recording device of your choice (as audio in feeding a recording software using analog-to-digital converter). I don't believe that there are software solutions for generic capturing analog-out into a waveform file, but the respective synthesizer may provide such an option.
    – guidot
    Nov 8, 2019 at 9:59
  • Do any of these work as plugins… VSTi etc? If so, most DAWs have an option to 'print' the midi via the plugin directly to an audio track.
    – Tetsujin
    Nov 8, 2019 at 10:13
  • @trolley813 I don't see any straight-forward way to do it (forwarding). Nov 8, 2019 at 23:38

2 Answers 2


If you work with music software on Linux, I suggest you look into Jack. It is a virtual patch panel that can route midi signals and audio from one music application to another. So you could patch the audio output of ZynAddSubFX into a DAW like Ardour or Qtractor. Many Linux music programs support Jack. QjackCtl is a graphical user interface to Jack that makes it easier to use.

Jack can be found at https://jackaudio.org/ and it's in many Linux repositories.

  • Jack is an excellent tool for serious audio work but for a simple task like this it's overkill.
    – PiedPiper
    Nov 8, 2019 at 11:47
  • @PiedPiper so is PulseAudio (and that is in many ways much worse suited for professional audio). Really those synths should just be loaded as plugins into the DAW, like anybody would do with commercial e.g. VST synths... but I'm not sure if LADSPA etc. is by now actually up to the task, alas when I last checked pro audio in Linux was still a big mess. Jack remains the way to go. Nov 8, 2019 at 15:50
  • @leftaroundabout The question isn't about professional audio. Pulseaudio is also not the ideal solution, but it does come preloaded on most systems, and it's good enough to solve OP's problem.
    – PiedPiper
    Nov 8, 2019 at 16:04
  • @PiedPiper pro or not, I think PulseAudio is just not capable of doing this kind of routing with sufficiently low latency etc. to be ok for recording. I haven't tried it lately so not completely sure; if it does work for the OP – fine, but I certainly can't second the recommendation to use it. Nov 8, 2019 at 16:22

You can do this with almost any recording software. Instructions for doing this with Audacity via Pulseaudio can be found at the Audacity web site. Here's a summary:

  1. Installe PulseAudio Volume Control (pavucontrol)
  2. Ensure that PulseAudio is running. In Audacity's Device Toolbar, set the Host to ALSA and the recording device to pulse.

  3. Ensure that "Software Playthrough" is not enabled in the Transport Menu then left-click on the Recording Meter to turn monitoring on.

  4. Open PulseAudio Volume Control and choose the "Recording" tab.
  5. In the "Capture from" dropdown, select the "Monitor" option of the playback device used by the application you want to record from.
  6. Launch the application that you wish to record and begin playback.
  7. Set the recording level in the "Recording" tab of PulseAudio Volume Control.
  8. When the recording level has been correctly adjusted, press the Record button in Audacity .

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.