Hydrogen Manual

Antonio Piraino

Alessandro Cominu

Hydrogen is a software synthetizer which is able to be used either by itself, emulating a drum machine based on patterns, or via an external MIDI keyboard/sequencer software.


Table of Contents
1. Introduction
1.1. Download
1.2. Build
1.3. Audio driver configuration
1.3.1. OSS audio driver
1.3.2. Jack audio driver
2. GUI
2.1. Song editor
2.2. Pattern editor
2.3. Mixer
2.4. Menu
2.4.1. Preferences
2.4.2. Audio engine info
2.4.3. Drumkit manager
3. A new song
3.1. "Song" and "Live" mode
3.2. A new pattern
3.3. A new sequence
3.4. Adjust from the mixer

Chapter 1. Introduction

1.1. Download

The latest stable version of hydrogen is available at http://hydrogen.sourceforge.net

It is possible to download the source files directly from CVS snapshots with:

bash$ cvs -z3 -d:pserver:anonymous@cvs.hydrogen.sourceforge.net:/cvsroot/hydrogen co libhydrogen
bash$ cvs -z3 -d:pserver:anonymous@cvs.hydrogen.sourceforge.net:/cvsroot/hydrogen co hydrogen


1.2. Build

After having downloaded and decompressed the tar.gz files there's only to:

bash$ cd libhydrogen-*
bash$ ./configure
bash$ make
bash$ su -c "make install"
bash$ cd hydrogen-*
bash$ ./configure
bash$ make
bash$ su -c "make install"

Before compiling, check for additional options with:

bash$ ./configure --help


1.3. Audio driver configuration

It's very important to choose the proper audio driver for our system, since the choice may influence quite much general performances. The choice is between Oss Audio Driver and Jack Audio Driver.


1.3.1. OSS audio driver

The Oss audio driver uses /dev/dsp and it's based on the OSS interface which is supported by the vast majority of sound cards available for linux; this said, the use of this audio driver blocks /dev/dsp until Hydrogen is closed i.e. unusable by any other software.


1.3.2. Jack audio driver

The Jack audio driver needs its server running (Jack Audio Connection Kit), a professional audio server which permits very low lag and exchanges with other audio software.


Chapter 2. GUI

2.1. Song editor

In the frame "Song Editor" there is the song we are creating with 5 buttons:

Create a new pattern (asks for a name)

Move selected pattern down

Move selected pattern up

Call a menu to modify properties concerning the song (name, author, comments), to erase the pattern sequence or every pattern created.

Repeat the whole song

Under these buttons there is a list of patterns created and when they will executed. Click on an empty squarebox to submit or cancel the pattern (indicated as an 'X'). Clicking on right mouse button over a pattern will bring up a menu to change name of the pattern, to copy or delete it.

Clicking on right mouse button over the name of a pattern in the frame "Song Editor" and choosing "pattern properties" will change its name. Patterns with very same name are not allowed.


2.2. Pattern editor

The "pattern Editor" frame let us create or modify the pattern which is being played, add or remove notes and tune intensity (hard or soft beat). The combobox "Grid Resolution" will modify the resolution so to help adding notes: it's possible to set grid for 4,8, 16, 32, 64 beats and their ??? indicated as 4T, 8T, 16T, 32T, 64T. You can also set che number of bars actually played by the "pattern size" menu on the right (1 to 8). Selecting an instrument which already has at least one beat on screen will popup a few vertical bars on the lowest part of this frame to allow tuning 'hard' or 'soft' beat. The button (hear new notes) will play the sound as it's been added to the pattern


2.3. Mixer

The "Mixer" frame is useful for tuning global or single volumes of the current drumkit. It shows various infos as the current peak and maximum peak, lets you modify attributes like pan and volume , play solo , mute , load a WAV/AU/AIFF sample for an instrument or play only that instrument .

Double clicking over the name of an instrument in the "Mixer" frame will bring up a dialog to modify properties. Switch MIX/FX buttons to modify effects.


2.4. Menu

From the pull-down menus it's worth noticing: File-->'Save as' to save the current song in .h2song format, File-->Export to export it in WAV format, File--> Preferences, Window--> Audio Engine Info and Window--> Drumkit manager.


2.4.1. Preferences

From this tab it is possible to modify the audio driver being used (OSS or jack) with its buffer and sampling rate plus the metronome (on/off) and its volume. [e le altre ozioni che non so' cosa fanno ...]

Clicking on Midi System will select a menu to enable a MIDI device, a specific channel or all of them.

Clicking on "Appearance" lets you to modify font size, type of frame (Child or Top Level) and speed of mixer's peaks falloff.


2.4.2. Audio engine info

This tab will bring up a window with general infos about Hydrogen and audio driver. Buffer and sampling rate of jack audio driver are customizable when the server is launched from the shell.


2.4.3. Drumkit manager

The drumkit manager shows all the options concerning drumkits, i.e. groups of sounds (wav) to be binded with every track available so to obtain a proper "groove" according to the situation (disco music, rock, hip hop, etc.). To let you have a rough idea of a good example of use of these drumkits, it is advisable to play the associated .h2song sample.

From the first screen we can load/delete the drumkit, with a short description

Here we can save some infos about the current drumkit

From here we can import a drumkit (.h2drumkit) ...

... and export it.


Chapter 3. A new song

3.1. "Song" and "Live" mode

Hydrogen has 2 main modes: "Live" mode (selecting ) and "Song" mode (selecting ). When "live" mode is activated the current pattern is continously repeated, so to help changing it until we dont like it, while "song" mode repeats only once the current pattern: this is useful when putting together the patterns, to create the whole structure for the song.


3.2. A new pattern

We'll start from an empty song with an empty pattern, as created by default: "live" mode should be selected now. It is also possible to change name of the pattern. Note che CPU load and MIDI applet.

Let's click on and while the pattern is playing lets add notes in the grid simply left mouse clicking on it: adjust grid relolution and BPM speed if needed. Default is 32 for grid resolution and 120 for speed (within a range of 40-300). Click on to stop pattern playing. To create new pattern just click on and proceed as explained to add notes, be sure to select the correct pattern before adding notes!


3.3. A new sequence

Once patterns are created, to copy/paste/delete or move them in the pattern grid we can use the buttons in the frame "Song Editor" , and the copy/delete command that pops up right mouse clicking on the pattern selected.


3.4. Adjust from the mixer

Of course we can always open and use the mixer window, either when creating or playing patterns.

The Mixer frame is made of 32 independent tracks, each of these is binded to an instrument, plus a "Master Output" line to adjust general output volume and a "FX" button to set effects. Every line features 4 buttons ( ), delay and pan adjust ( ), current maximum peak, volume fader e name of the track. Clicking on will play the selected instrument, cutting the others. The "Mute" button , simply mute that instrument. The maximun peak indicates the maximun volume reached from the instrument; the peak must be in a range of 0.0 and 1.0, otherwise it will get distorted producing a weird sound (especially with OSS audio driver), in these cases it's better to lower volume down.

Finally there is the volume fader to adjust volume of that instrument and check the peak reached thanks to a vu-meter behind the knob.