Connect

Prerequisites

The only prerequisite after all the work we did for setup and installation is to install hydrogen.

Installing Hydrogen on Arch Linux

sudo pacman -S hydrogen

Setup

Hydrogen, at least on my Arch Linux, is set up to connect to the default JACK audio output. To disable that, open the settings menu Options -> Preferences and select the Audio System tab. Uncheck the Connect to default JACK output ports options. Restart hydrogen afterwards.

Hydrogen should now start without automatically connecting the audio outputs.

Fire up PMX-1

The various services for the PMX-1 back-end are implemented with systemd in mind and should be started as a user service. To manage the services and monitor the logs the systemd tools systemctl and journalctl can be used.

An easier way to control the mixers services is to use the provided PMX-1 console application pmx-console which provides easy access to the main mixer management tasks. The easiest way to to set up the console, start the parameter monitor and systemd log streaming in one go is to use the provided debug script pmx-debug-tmux.fish, which uses tmux to create a viewer like show in the following screenshot.

The script starts tmux with pmx-console in the first window, journalctl following the user logs in the top right window and pmx-params-monitor in the bottom left corner, displaying the parameter changes in real time.

First we will check if the services are already running. Select the top left window, the one running pmx-console and run the status command. The output should be something similar to the following:

pmx-console

pmx ~> status
pipewire.service active
wireplumber.service active
pmx-filter-chain-ctrl.service  enabled
pmx-grpc-api.service  enabled
pmx-metadata-manager.service  enabled
pmx-midi-router.service  enabled
pmx-osc-network-receiver.service  enabled
pmx-osc-network-sender.service  enabled
pmx-traktor-z1-router.service  enabled
pmx-filter-chains.service  enabled
couldn't find producer pmx-midi-router
couldn't find producer pmx-osc-network-receiver
couldn't find producer pmx-traktor-z1-router
couldn't find consumer pmx-filter-chain-ctrl
couldn't find consumer pmx-osc-network-sender
pmx ~>

In this case, pipewire and wireplumber are running, but the PMX-1 services are only enabled and not running, because no other service actively requested them. To start the services run the start command. This will spark a flurry of activity in the log and the params watcher window, but ignoring those for now, the output of the start command should be a new line, which indicated that no error occurred and systemd accepted the command. Beccause systemd starts the services asynchronously, this doesn’t mean the services were started successfully, so we should run the status command again and if the output is something like the following, we’re good to go.

pipewire.service active
wireplumber.service active
pmx-filter-chain-ctrl.service active
pmx-grpc-api.service active
pmx-metadata-manager.service active
pmx-midi-router.service active
pmx-osc-network-receiver.service active
pmx-osc-network-sender.service active
pmx-traktor-z1-router.service active
pmx-filter-chains.service active

Otherwise, unfortunately, the services weren’t started successfully and troubleshooting is the name of the game. If you’re stuck, head to the Community section and ask for help.

Connect Using the Admin UI

Start the admin UI based on the chosen installation method from Install. Open the browser and navigate to the admin UI, normally available at http://localhost:5078. Navigate to the Inputs tab. Here the Admin UI presents the configuration of the 16 stereo input ports of the mixer.

We will connect Hydrogen to channel 1 of PMX-1. First, set the channel up to be a stereo channel. Make sure the stereo checkbox for channel 1 is checked.

Select the ports names and for the left and right source channels of channel 1 as shown in the following screenshot.

If you start the playback in hydrogen now, it should be audible.