# Linux audio

## Ontology of Linux sound systems

TBD. Include the different standards, sub-standards, compatability layers, compatabiility layers standards, legacy and surly coexistence APIs.

## Doing stuff with Jack

JackAss routes midi from jack-blind hosts:

JackAss is a VST plugin that provides JACK-MIDI support for VST hosts. Simply load the plugin in your favourite host to get a JACK-MIDI port. Each new plugin instance creates a new MIDI port.

### virtual ports for bidirectional patching

• How do I refer to a soundcard so that the name always works?.
• difference between qjackctl and patchbay.
• beginner's guide to jack via a DAW (Ardour)
• internal routing with JACK explains why you can't make it do what you expect with routing sub-buses to different apps - you need lotsa virtual channels:

With a basic implementation of JACK now set up, we can begin to tweak JACK to our needs—internal routing. For those of you with larger 8-channel interfaces, you probably have noticed a slight problem with JACK: you do not have all eight microphone inputs available anymore! This is because we need to tell JACK how many inputs we want (both in and out).

For OS X users, simply adjust the Virtual I/O settings under Preferences until your hearts content and you should be good to go. For Linux and PC users however, things are not so easy. While the Channel I/O option sounds like a perfect match, it really does nothing most of the time. Instead we need to edit an .INI file.

• Close down JACK, as well as any connected apps.
• Go to where you installed JACK (most likely C:\Program Files(x86)\Jack).
• In the 32 or 64 bit folder (depending on what version you are using) there is a file called JackRouter.ini
• Open JackRouter.ini with Notepad, and change the input and output values to however many channels you want. Presto!
• Restart Jack Control, enter your DAW, and you should now have a multitude of inputs and outputs at your disposal.

perhaps this is /etc/jackdrc and ~/.jackdrc on ubuntu? Ubuntu recommends using a GUI for config then persisting to disk. How to add extra sound cards to your jack setup

TBC.

## Doing stuff with Pulseaudio

Manuel Amador Briz CC BY-SA 3.0, .

### Cooperating with Jack

pulseaudio-module-jack and pasuspender methods briefly mentioned.