Hydrogen

Submitted by Tim on Fri, 09/21/2007 - 17:02

Our fictional flightless friends, Pengwyn Parc are in the studio preparing for their forthcoming single release.

"We should work on the drum parts first," says Tabitha,

"We've got to get the drum track right - it's the basic groove of the song."

Baz agrees, for once "Yeah, it's common practice in multitracking situations to record the drums first, otherwise it all gets out of time really quickly."

"I've done stuff where I recorded the guitar first, then keyboards and overdubbed some percussion as an afterthought." muses Kenny.

"I bet it was a mess." sniggers Baz

"You could just as well start with a rhythm and build it all up from that." Tabitha re-iterates.

Ashlee doesn't know, "It is not a hard and fast rule, it depends on the mood of the piece you are trying to create, surely?"

The crew have to agree to disagree on that one and get on with recording, this time they'll start with the drum track. They have decided to work on one of Kenny's songs that has been going well in rehearsal, while Tabitha and Baz search for a suitable application to use for writing the drum part, Kenny strums through the song on his guitar, noting down in his creative diary how many bars each verse and chorus take, not forgetting the intro and outro and any bridge sections.

And the beat goes on

Baz and Tabi decide on Hydrogen. Its main stated goal is to provide professional yet simple and intuitive pattern-based drum programming. Sounds good enough.

Tabitha immediately gets to work in the Pattern Editor sub-window. Down the left-hand side is the list of the various components of the drum kit with an empty four-beat timeline in the main part of the window. Along the top are various boxes, which allow us to alter different parameters of the riff: The first box allows us to cycle through the patterns listed in the Song Editor and the contents of the second box change accordingly. The size box allows us to choose the pattern length, slightly confusingly in eighth notes, so the default setting of 8 gives us a 4/4 bar. Setting it to 7 would give a 7/8 bar, setting to 10 gives a 5/4 bar, go figure. Tabitha sets it to 16, which creates a double 4/4 bar pattern effectively. Resolution affects the quantisation, i.e. the number of playable beats in the bar expressed as note-length values. Tabitha chooses 16 to allow 16th notes to be played. It is also possible to select triplet quantisation, so 16T actually divides a 4 beat bar into 24. This is probably obvious to anyone who has learned to read music, but Tabitha, who plays by ear, thinks it's a bit daft.


The last panel is the recording panel. There are two ways to record into Hydrogen, real-time or by hand; for real-time work you probably want the three buttons engaged - Hear Notes, Record and Quantise - if you don't have a MIDI keyboard attached to your set-up, you can use the keys of your ASCII keyboard, if you are entering notes using the mouse then you probably don't want these functions.

Laying down the groove

Tabitha starts by laying down a basic beat; eighth notes on the closed hi-hats, bass drum on beats 1, 3, 5 and 7 and snare on 2, 4, 6 and 8. This gives a rugged, but rather basic beat, which allows Tabi a chance to check the tempo. This she does by getting Kenny to play along on his guitar while she taps the backslash key repeatedly in time with the song until they agree on the timing they want. Hydrogen then sets the BPM of the track accordingly and displays that information in the BPM indicator on the bottom bar of the main window along with the Transport controls. The BPM can be altered using the mouse wheel for incremental fine-tuning.


Next, she adjusts the pattern to fit Kenny's playing better. To start with, she thins out the hi-hats to four in a bar, adds a few grace notes and open hi-hats, and then changes the timing of one of the bass drum beats to give the second bar a bit of a 'push'. Being a drummer, Tabi knows that not all beats in the bar get the same weight, so she edits the velocities displayed along the bottom of the Pattern Editor sub-window, by clicking and dragging them to more appropriate values. Right-clicking on any of the instruments in the Pattern editor sub-window presents a sub-menu of helpful options to Mute, Lock, Solo, Fill and Clear notes relative to the grid resolution set and create pseudo-random velocities for that particular instrument. The Lock function locks the instrument belonging to a drumkit on that pattern even if you change drumkit, which allows you to mix and match drumkits. Tabitha tries playing around with random velocities.


Chaining it together

When she's got a pattern she's happy with, Tabitha saves the song in Hydrogen's native .h2song format. So far we have a good basic beat, but this song has some odd timing changes and needs fills, so Tabi moves over to the Song Editor sub-window. The song editor lists the patterns in the left margin with the main window being a matrix-grid timeline. This allows you to arrange the patterns in sequence. At the top of the left margin is a row of buttons that control: completely deleting all patterns, creating new patterns, reordering the pattern list and switching between selection (to allow copying, pasting and moving) and draw mode. Right-clicking on the pattern names in the left margin gives you the further choices of editing the pattern in the Pattern Editor sub-window, copying and deleting the pattern, filling or clearing bars of the song sequence with that particular pattern and editing the pattern's name via the Properties option. Tabitha changes 'Pattern 1' to 'Main Riff' and then copies it to 'Main Fill 1' and 'Main Fill 2', remembering to select the pattern she wants to edit before continuing.


In order to hear how all the patterns work together it is necessary to switch to song mode using the mode selector on the transport bar. By switching backwards and forwards, copying and altering sections, Tabitha soon builds up enough parts for a complete verse and chorus. She realises that she's forgotten to make an intro bar, so she copies the bridge pattern, renaming it to 'Intro' and edits it, removing everything but the final fill. She now needs to move the pattern sequence along by one bar. By going into selection mode it is possible to click and drag to select an area of patterns and then click and drag them to the desired position.

Selecting the right sounds

Tabitha is bored with the default drum sound, she needs something with a more 60's feel. The Drumkit Manager can be accessed from the View > Show drumkit manager menu entry and provides a range of alternative drumkits, which can be loaded while the song is playing to allow you to easily preview the sounds. The drumkits vary quite widely in sound and can strongly affect the final feel of the track.


Next Tabi wants to add some effects to give the track some atmosphere. Effects are controlled via the Mixer sub-window.

The main part of this window is laid out rather similarly to an analog mixer, each component of the drumkit gets its own strip with controls to preview, mute, solo and pan the sound, four rotary pots to control FX volume and a vertical fader for the overall volume.

The interesting controls are on the right-hand panel. Next to the Master Fader that controls the overall volume, are the Humanize functions and two buttons - the top one toggles the peak level meters on and off and the lower brings up the FX panel.

Here we can have some fun. We have four effects channels available to us, Tabitha clicks on the Edit button of the first, which brings up a LADSPA properties window. She clicks on the Select FX button, which brings up a further selection window with all the possible LADSPA effects listed in the left-hand window. She selects TAP Reverberator and then turns it up using the first FX pot on the mixer strip of the snare and cymbals, leaving the bass drum dry. Less is more, exponentially so with reverb.


For an added touch of realism, Tabitha plays around with the Humanize function. It is possible to randomise the velocity and timing of each note played and also specify a swing factor - the amount of bounce or 'dottedness' applied to the rhythm, this can be essential for some swing jazz, reggae and hip-hop feels. Careful use of these controls can really bring a drum track alive and make it sound almost organic.


For more fine-grained control of the sounds, Hydrogen provides the facility to edit the individual components of the kit. View > Show instrument editor. Using this interface it is possible to create your own custom drumkits with up to 16 layered samples and apply an ADSR envelope, filter and pitch effects for each instrument.


Cutting the rug

In order for this drumtrack to be useful to other applications it is necessary to export it as a stereo audio file, in fact the only choice here is .wav. Hydrogen will export the file at whatever sample rate it is currently running at. Go to the Audio System tab of the File > Preferences dialog if you want to change settings. This same dialog allows you to control MIDI settings and the visual appearance of Hydrogen. File > Show song properties brings up a dialog that allows you to name the song and add comments. Once all the details are set, File > Export song brings up a file browser dialog where you can give it a name and then click on the Export button and wait for the progress bar to reach 100%. It is also possible to export the track as a MIDI file or hook Hydrogen up to an external MIDI source directly, so it can be run synchronously with other sequencers or multitrack recorders.


links

Hydrogen
http://www.hydrogen-music.org/

Jackbeat
http://www.samalyse.com/jackbeat/

Drum Patterns
http://www.linux-france.org/prj/drumpatterns/index-en.html

Smack
http://smack.berlios.de/