Monday, 1 June 2009

Recreating Boards of Canada's Roygbiv Bassline

Boards of Canada's Music Has the Right to Children is an album full of intriguing synthesizer lines and processed sampled sounds. Perhaps the most recognizable is from Roygbiv; a phat, laid-back slice of analogue nostalgia. Roygbiv, the name taken from a mnemonic for remembering the orders of colours in the visible spectrum, opens with a deceptively simple bass sound. It is this bass that we will recreate.

Whilst the Scottish two-piece are notoriously cagey about techniques and equipment, they are known to make good use of analogue synths. The bass in question is likely a Roland SH-101. Aspect excels at recreating these analogue style sounds. The Aspect evaluation can be downloaded here in VST Plugin, Audio Unit, RTAS, and Standalone formats for Mac OS X, Windows, and Linux.

Start, as all good sound designers generally do, with the initial patch by choosing New Program under the File menu.

The bass is obviously monophonic, so leave the Polyphony set to 1. The general rule for subtractive synth sound creation is, start with the oscillators. Oscillator1, set to 100% in the Mixer, should be dialed to Sawtooth. Oscillator2, also 100% in the Mixer, should be set to the Pulse shape with a Pulsewidth of about 75%, and detuned down an octave (turn Oscillator2's Octave rotary to -1). Finally, a little noise helps add some grit to the sound: set the Noise level in the Mixer to about 21%.

Oscillator settings for Roygbiv bass
The bass sound has a fairly simple amplitude envelope shape. Set Envelope1's Attack and Decay to their lowest setting (1ms and 5ms, respectively). Set Sustain to 100%, and Release to about 4000ms. This gives a punchy bass sound with a fairly long tail.

Envelope settings for Boards of Canada's Roygbiv bass
Even small changes to the filter produce huge changes in this sound. As is normally the case with bass sounds, we'll use a Lowpass filter. Set the Filter1's Cutoff to 33%, and set the keyboard tracking modulation (called Note Pitch in the modulation menu) to about 75%.

Sounds nice, but lacks Roygbiv's growl. We can fix that. Assign Envelope2 to Filter1's modulation with a depth of 61%. The appropriate envelope shape should have a quick Attack and a slow Decay/Release. Let's use Attack 25ms, Decay 2500ms, Sustain of 45%, and Release of 3000ms. A filter Resonance of about 2% adds the necessary bite to the sound.

Boards of Canadas Roygbiv bass filter
A few last tweaks introduce some analogue authenticity. A slow wavering of the pitch adds some subtle warmth to the sound. Set LFO1 to a rate of about .30Hz, and route it into Oscillator1's second Pitch Modulation Slot with a depth of a few cents (0.02 semitones sounds good). Likewise, set LFO2 to a rate of about .10Hz, and route it into Oscillator2's second Pitch Modulation Slot, this time with a depth of about 0.09st.

Aspect's second filter can be used to grunge up the sound a tad. Route Filter1 into the Input of Filter2, and set Filter2 to Highpass with a Cutoff of 0%. The Output Filter Mix should be about 15% to add a small amount of the high-passed signal into the chain.

Finally, turn on Always Glide in the Global section, and set Glissando to 12%. This provides the sliding movement between two consecutive notes played at different pitches.

So here is the Roygbiv subtractive synth patch for Aspect, and this is what the recreation sounds like.

The fairly heavy reverb present in the original song is here provided by Apple Logic's AVerb plug-in. Adding a warm tape-style compression and some subtle eq would likely produce a more authentic sound. This is left as an exercise for the reader.


  1. I just A/B'd the recreation with the song itself and it is mighty fine - close enough that a little TLC should make it spot on. Any chance BOC had an alpha copy of Aspect in 1998?

  2. well, I just confirmed my suspicions with my SH-101. They definitely use it on that tune. At first I thought maybe it was a minimoog line or a modular synth because you can hear an oscillator beating out of tune, but it turns out they're just setting the pulsewidth on the square wave of the SH-101 to LFO to create that effect.

  3. That sounds great kermit, good job!

  4. Well done. I don't have Aspect, but I used this recipe, more or less, on my DSI evolver. I turned off the 3/4 digital oscillators and was able to get pretty close with just the 2 analog osc. Not exactly, but close enough so that I can deviate and program my own bass sounds.

  5. Thanks Loomer! The SH-101 is a wonderful little synth. Its beauty comes from its simplicity. You can get an awful lot out of it, so I see why BOC uses it so often. The VCF on it is killer, and I have yet to encounter a modeling synth that can match it, even though I love my little Novation Xio Synth.

  6. out of curiousity: how do u patch the aspect synth with an xml file?

  7. If you're using the demo version, you can't open XML files, so you're limited to either your own presets or the factory bank.

    To load an XML preset into the full version, you just need to put the XML somewhere in the preset library folder. The quickest way to access this is to open the preset browser by clicking on the preset name at the top, right-click on the 'User' node, and choose 'Show In Finder/Explorer'. This will open the preset library root in Finder or Explorer, into which you can simply drag the XML presets.