JACK Synthesizer Manager Proposal

Audun Halland and I have been thinking about a set of related problems in the realm of Linux audio. The first result is the following proposal, meant to gather feedback from the community via the LAD and LAU mailing lists.

JSM, the JACK Synthesizer Manager

We propose a programm that acts as a proxy between sequencing software and both software and hardware sythesizers. Among the goals are unified patch selection and making projects more portable.

If we get the impression that the JSM is something that both developers and users will find handy and use, then development might start real soon.

In this text, we avoid going into technical details to foster free thought and discussion.

Use Cases

Patch selection

Goal: Choose patches from all available hardware and software synthesizers.

Giorgio uses a single means to select a patch among all patches of all of his software and hardware synthesizers. He uses meta-data to find the right patch. The right connections are made automatically.

Computer as syntheszier

Goal: Use the computer as a compound synthesizer in a live performance.

Hiromi has her keyboard connected to her laptop live on stage. She uses several soft-synths via keyboard-split and layering. A few selected parameters are bound to the wheels of the keyboard. After each song, she switches from one setup to the next with least effort.


Goal: Exchange projects without having to change settings back and forth.

Alice and Bob take turns on working on a project. They use different hardware but don’t have to manually change connections and choose patches on each turn because of an abstraction layer.

MIDI Interface Ports

The problem with MIDI interface ports is that the hardware on the other side and its setup might change. Or be entirely different if people exchange projects. An abstraction layer can make this more comfortable to handle.

The JSM takes care of the mapping between software ports and MIDI interface ports. It can work on a per MIDI channel level.

Patches and Instrument Definitions

Patches and controllers are chosen by name; the user doesn’t have to deal with cryptic numbers. For kit-programms, name mappings are given (e.g. bass drum on C1).

Patch selection happens by a single means, offering all available patches (JACK apps, plugins, hardware). Making the required MIDI and audio connections is automated as far as possible.


Categories help to find the right patch among many. When exchanging projects, they help to replace unavailable patches with similar ones.

Virtual/Compound Synthesizers

From the outside, the computer can be dealt with like a single compound synthesizer. Different synthesizers can be triggered from ranges on a single keyboard (key splits). Synthesizers can be layered. The whole setup can be switched with programm changes.

JACK to ALSA Bridge

JSM could be the de facto JACK MIDI to ALSA MIDI bridge. No Jack “SYSTEM” midi ports, the jack world only sees the devices offered by JSM.

Audun Halland and Thorsten Wilms

Music: Woxitron WIP

It all started with a single custom drumloop run through dozens of plugins, cut into pieces and rearranged to retrieve several versions that can be layered. That was years ago, using Cubase. Now I feel slightly awkward about not using purely free software , but this material is way to good to leave it 🙂

I took those few short loops and a bunch of other old samples to build a track in Ardour. Said samples include me screaming into the mic, a car and a lorry passing by on a wet street and a soda stream.

So far its almost all percussion. I intend to add melodic parts. Usually I build a “core” of a piece, consisting of 4 to 16 bars with complete instrumentation, but here I have a skeleton now 🙂

I made this WIP snapshot to gather some feedback, as I wonder if the breaks and transitions are maybe a bit rough and whether I should extend some parts to provide stability.

Ogg Vorbis