If i am using the GNU-licensed software "Open Metronome" (https://sourceforge.net/projects/openmetronome/) to create the basic rhythm of my own music, I am wondering if I can freely distribute the resulting music (including commercially)? Or if I am bound by the GNU license terms?

This software basically creates a very simple beat based on your choices of instrument (clapsticks, bass drum, etc.) and the speed that you select (bpm). I am wondering if the sound of the instruments in this software is somehow copyrighted and would restrict me from using it freely?

I understand that the OUTPUT of a GNU licensed program is generally not covered by the GNU license, but I also read that an exception is where the software contains any art or text that is also showing in the output. In this case, I am wondering if the sound recording of the different instruments would qualify as such?

  • From a quick look at the project: is it in any way specified under what license the WAV and/or MIDI voices are made available? (Were they created by the project author? If not, the project author quite possibly doesn't have the right to release them under the GPL in the first place) Jun 4, 2023 at 11:22
  • 3
    You should probably read this question and its answers, then let us know if that has dealt with your question (and if not, what remains to be answered).
    – MadHatter
    Jun 4, 2023 at 12:36
  • For this particular package, it seems that the sound samples themselves have a separate license file attached. Please look at the readme file(s) inside the archives Samples_Original.zip and Samples_Fluid.zip. I suspect 'fluid' refers to FluidSynth. For that program, the situation is the same. Here is the directory which contains the license file for the FluidSynth samples: github.com/FluidSynth/fluidsynth/tree/master/sf2
    – Brandin
    Jun 6, 2023 at 6:57
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    As for whether 'using' such samples to make one's own work itself would be considered a derivative work of the samples (e.g. in the absence of an explicit license) is a more complicated legal question and it's probably better to clarify that on law.stackexchange.com if you have a legal question about that.
    – Brandin
    Jun 6, 2023 at 6:59
  • @Brandin I am sorry but I don't exactly understand what FluidSynth has to do with OpenMetronome?
    – Cori
    Jun 9, 2023 at 12:34

1 Answer 1


Unfortunately, this program is very complicated. As you mentioned, the GNU GPL does not apply to exiting a program unless it copies itself there. So unless the samples you use are under the GNU GPL, neither will your music.

I downloaded the Samples_original.zip and Samples_Fluid.zip archives, and it looks like Samples_Fluid SHOULD contain Fluid SoundFont samples. I downloaded a copy of it from the Web Archive Wayback Machine (https://web.archive.org/web/20121015090653/http://soundfonts.homemusician.net/files/FluidR3122501.zip) and it looks like (in the FAQ, so not a formal license) you can use this soundfont, and donations are welcome but not required.

There are various samples in Samples_original.zip, for example from freesound. I looked at one of them (https://freesound.org/people/FranciscoPadilla/sounds/22742/) called 39 Hand Clap. It is licensed CC-BY-NC, i.e. non-commercial use. But after going to the Wayback Machine (https://web.archive.org/web/20111016150352/http://www.freesound.org/people/FranciscoPadilla/sounds/22742), I saw that it used to be available under the CC Sampling+ license (special license for sampling, see description here).

Unfortunately, researching so many samples is a bit of work, so if you care, you'll have to check everything yourself. If you do, you can share your report with the OpenMetronome project by uploading your it to SourceForge discussions.

For you, however, the safer option would be to make your own samples or find CC0 or other alternatives and replace the files from these archives. Just e.g. for hand clap, clap yourself and record it.

I didn't find any music files in the source code, so the only sound that can come from these sources is synthesizer.

This is not legal advice

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