An Introduction to Hydrogen

Find out why Dave is so excited about this drum machine/rhythm programmer.
General Organization

Hydrogen's user interface is made of a main parent window with a top-level menu bar and a set of play/record controls. This main window opens with its editor and mixer panels displayed. By default, Hydrogen displays the most recent work file upon opening, including any panels displayed when the file was last saved, but that action can be toggled from the File/Preferences dialog.

The main window's File menu supplies common operations such as new/open/save, export to MIDI and WAV and the program preferences settings. The Window menu is a list of show commands if you've hidden the song and instrument editors or the mixer. This menu also calls the drumkit manager and an audio engine status window, both hidden by default. The ? menu is Hydrogen's help menu for accessing the user manual and a tutorial.

The transport bar includes start/stop controls, pattern and song mode selectors, a tempo control scrollbox and status indicators for JACK, MIDI input and CPU load. That's all there is to describe for Hydrogen's main window functions, so now we move on to the various editor panels.

The Pattern And Song Editors

Figure 2. The Pattern Editor

Pattern and song are related closely in Hydrogen's interface. Patterns are selected, named, copied, added and deleted using the Song editor, and clicking on the pattern name in the song editor window immediately activates the pattern editor for the selected pattern. By default, the song editor provides ten blank patterns, but you can add as many as you need. Right-clicking on the pattern name pops up a menu for copying, deleting and naming the selected pattern.

The pattern editor panel presents a grid whose horizontal axis is the timeline along which you place beats and whose vertical axis represents the instruments played. Entering beats into a pattern is as simple as clicking on the desired coordinates point, resulting in a display similar to Figure 2. Each beat can have its own velocity and pitch setting, available in the lower panel of the pattern editor (the VEL and keyboard buttons). This panel can be toggled between velocity and pitch grids; Figure 2 shows the panel in velocity mode.

The left side of the pattern editor shows the names of the instruments assigned to their particular timelines. Left-clicking on the instrument name triggers its sound; right-clicking pops up a menu for mute/solo status and a clear/fill notes function. The fill function is useful especially if you like to shape your pattern by removing beats from a filled line. At this time, there is no undo/redo function for either pattern or song edits.

The pattern editor's controls are located at the top of the editor panel, as seen in Figure 2. These controls include a toggle for sounding the sample when a beat is entered into your pattern. There also are two controls for recording and quantizing beats entered from either the computer keyboard or a MIDI device such as a keyboard, guitar, wind controller or external sequencer.

The pattern editor control strip also includes the grid resolution and pattern length value selectors. The grid resolution can be set to a maximum of 64, with triplet resolutions up to the 32nd-note triplet. The pattern length determines the number of beats per measure, like the numerator in a conventional time signature, thus allowing odd bar lengths such as five or seven beats per measure.

Figure 3. The Song Editor

Hydrogen's song editor is its simplest panel. A song form is created by adding or deleting patterns in the linear track display; left-clicking on a box in a track enters or removes it from the form. Hydrogen allows the use of simultaneous patterns, a wonderful addition, especially for adding variations to an existing pattern. Of course, you can copy a pattern to an empty pattern slot and then edit it as you wish, but using a simultaneous pattern can be a more flexible approach to adding variations to an existing pattern.

The song editor's controls include buttons for adding a new pattern, shifting pattern positions, performing some song operations and toggling loop play on/off status. The song operations button calls a menu with an item for setting song properties (song name, composer's name and comments) and two controls for clearing a pattern sequence and deleting all patterns from the song form.

The Instrument Editor

Figure 4. The Instrument Editor

Up to 32 instruments can be used within a pattern. Each instrument can be a single sampled sound, or it may consist of up to 16 samples layered together for more complex sounds. Of course, your selected sounds need not be restricted to drum and percussion samples; they can be any sounds you like. Remember, a drum machine is essentially an audio sequencer, and Hydrogen can play any sound you tell it to play.

Hydrogen's instrument editor provides some nice controls for shaping your sounds, with parameter settings for layer properties and an ADSR (attack/sustain/decay/release) envelope designer. The editor also includes a neat control for random pitch fluctuation when the instrument is played, thus creating more realistic sounds. Yes, even percussion sounds have a pitch element. By the way, in Figure 4 you can see the scrollbox controls for the envelope values, but plans have been made for adding a graphic envelope editor.

An instrument's corresponding mixer strip also is shown in the instrument editor, a nice convenience when designing your sounds. By default, Hydrogen mutes unused channels, so be sure to un-mute your new instrument channel.


Similis sum folio de quo ludunt venti.


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does any audio software do this

Anonymous's picture

oh, and this one too. Pleas please if anyone knows of software that will let me do what this guy does on this machine with a similar tactile interface (computer keyboard) please let me know!!!!!

Not just for Linux either!

Anonymous's picture

Thanks to the support for OSS (Open Sound System) as well as ALSA, Hydrogen isn't just for Linux. I run it on a NetBSD machine, and it's an absolutely brilliant program. I do need to upgrade the version that's in NetBSD's package collection, which I've left languishing at version 0.8.x.

I just wish someone had the time and talent to make an ALSA compatability layer for NetBSD so I could run Hydrogen alongside Rosegarden. Then I could finally stop sequencing on my ancient Atari ST and Cubase.


still need real drum machine software

Anonymous's picture

I've tried dozens of apps like this and the just don't work for me artistically. They're just not NATURAL!

For YEARS I've been trying to find a piece of software that mimics an actual Drum Machine. Something that I can use just the (computer) keyboard to hit notes and trigger samples and loops. Still haven't found one. That's what the world really needs! Not another fruity loops or similar app. There are already too many like this.

These are drum machines: (pay close attention to 4:00 it's most important)

Noteedit and Hydrogen

Carl's picture

I've been using a combination of Hydrogen drum tracks saved to wav format and Noteedit tracks saved to wav. Set both to the same tempo and mix them using Audacity! You can balance the tracks by amplifying one of them and then mix them using 'Quickmix' and export as an mp3.

Correction re: GUI

Anonymous's picture

I mistakenly ascribed the GUI widgets designs to developer Willie Sippel. Willie kindly pointed out that the actual design is done by Christian Vorhof. Thanks to Willie for the correction, and many thanks to Christian for his excellent improvements to the Hydrogen GUI.

Best regards,

Dave Phillips

Re: An Introduction to Hydrogen

Anonymous's picture

I wish someone would get a driver for my Yamaha DSP Factory
also know as a dsp 2416 so I could ditch windows for midi also.

Same here. Can it be done?

Anonymous's picture

Same here. Can it be done?

I feel your pain...

Anonymous's picture

However, the only way that driver will ever happen is for owners to persistently (but politely) write to Yamaha and ask for either a driver from Yamaha or for Yamaha to release the needed specifications to the ALSA team. Alas, Yamaha has shown no indication that they'll do such a thing, even though it could result in more sales of their product. This short-sightedness re: Linux is a constant in the pro-audio industry, sad to say.



Author's additions

Anonymous's picture

I would like to emphasize the fact that the CVS version tested in this article may not necessarily reflect the features that will be included in the eventual "finished" public release. CVS versions should be considered as "testing ground" for new ideas and features, there is no guarantee that they will become the mainstream versions.

I also want to mention the outstanding work on Hydrogen's GUI, done by Willie Sippel. Willie's improvements are most likely to be included in the mainstream release. As you can see in the screenshots to this article he's made some very professional-looking improvements to Hydrogen's appearance, and I just thought they deserved special mention. Nice work, Willie !

Best regards,

Dave Phillips

Re: Author's additions

Anonymous's picture

Thanks Dave! But the graphic design was done by Christian Vorhof, a friend of mine. I did some usability/ layout work and implemented small parts of the interface, Christian designs the widgets (he knows next to nothing about music production tools, but he's a very good graphic designer).


Willie Sippel

Re: An Introduction to Hydrogen

Anonymous's picture

Another great article, Dave. I think Hydrogen is a great program, but it does have one flaw - no triplets! Unless I'm missing something, there is no way (or no easy way?) to put triplets and more general tuplets into a 64 box grid.

Re: An Introduction to Hydrogen

Anonymous's picture

I find this forum absolutley amazing.

Steve Z

Author's reply

Anonymous's picture

Triplets (up to 32nd-note triplets) are supported in the Grid Resolution drop-down menu in the Pattern editor, and the resolution can be changed in realtime.



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