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OMOrch - yet another OM interface to a Orchi***-tool


(- or the story of how Anders spent some cold and dark days during autumn 2023, trying to focus his attention on something else than CNN and Al Jazeera…)

OMOrch is YAOMO ('Yet-Another-OpenMusic-Orch…)-lib, bridging Carmine-Emanuel Cellas ‘Orchidea’ in to OpenMusic. I think it’s useful already.

OMOrch sources are here: GitHub - andersvi/OMOrch: OpenMusic library - interface to Carmine Cellas Orchidea software. As well there’s a release here


The library can be installed in the usual way. The sources include a README and a DEMO-workspace which can show some typical usage.


OMOrch provides classes and methods to control and call Orchideas’ ‘orchestrate’ cli, and store the output in variuos ways: sound, chord-seq, multi-seq, voice, poly…

OMOrch provides a special ‘orch-note’-class, with slots for various metadata such as instrument, playing-style, dynamics, sample etc. Some of these can be displayed in OMs relevant editors (sound, poly, multi-seq, chord-seq, voice), and forwarded to music-notation packages (LilyPond using Karims omlily, or musicxml).

OMOrch has a special voice-allocation algorithm allowing voices to overlap two or more segments (to see, choose the ‘dur’ view in multi-seq).

Atm. OMOrch uses the cli-version of Carmine’s Orchidea (http://www.orch-idea.org/download/). Linux-users will find the necessary Orchidea cli-tools (‘orchestrate’ is really all you need) already installed in resources/bin.

Orchidea needs an accompanying ‘SOL-type’ sound-database. Typically you’d want to install the ‘FullSOL’ and ‘TinySOL’ databases:


The OMOrch-lib still has some rough edges, and i hope to bring it more into shape with time. Some missing features are planned or are on their way. Check the ‘issues’-pane at the repo for a list of some enhancements and issues i already know about.

I’m very happy for feedbacks of all sorts. Check the README for some guidelines. Have fun!

OMOrch owes much to other “Orch…” libs made for various versions of the Orch…-tools, in particular Geof Holbrooks OM-Orchidea and Jean Bressons lib for Orchidée


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Dear Anders,

Thank you very much for this release. I am beginning to test it on Fedora 32. Only a little particular: after extracting the source archive the folder has to be renamed into OMOrc to be read by OpenMusic.



You’re right. Guess i’ll have to stop tagging the release at github then? Anyway, just rename the folder or make symlink to OMorch

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Just a quick note. For Linux-users, the FullSOL zip-archive from IRCAM is corrupt and won’t unpack using the normal ways. A hack is to use “jar xvf FullSOL.zip”

Just in case, perhaps i didn’t make it clear enough: OMOrch depends on a version of Orchidea’s cli-tools which runs on your platform.

The provided binaries in resources/bin are a courtesy for Linux-users (my version is compiled for Fedora 38. Probably better to follow up those kinds of issues in the Orchidea forum

Dear Anders,

Thank you for fast reply. About Linux I think I will update to Fedora 38 as soon as possible, so I would wait for that update to verify if something change.

Then some news if useful:

  • on OsX 10.13 High Sierra the library runs, only I had to copy CLI orchidea tools from Cella’s ones, because those of your library were not executed by my CPU or system. Substituting them it seems to me everuthing runs right

  • on OsX 10.13, again, the OM# version give me an error on loading the library: Error while loading the library OMOrch: “The file #P”/Users/fabio/bin/om-sharp/librerie/OMOrch/src/om-sharp-compat.lisp" does not exist." Indeed this seems a missing file, it i not comprised among your library files.

I hope these news are useful. Many thanks again for your work.



hose of your library were not executed by my CPU or system

I probably should have been more clear about this in the README: OMOrch depends on the cli-tools from a working Orchidea-installation

the OM# version give me an error

om# support is still on the todo-list. Should be very easy fix, give me a few days

Perhaps it’s better to move to the Orchidea forum for issues w. Orchidea? There are only some very few changes needed to compile the sources on any Linux. Might be useful for non-OM-ists as well…