Happy TB-303 Day!

At Tsugi, we love synthesizers, and since today is 03/03, we decided to pay homage to the famous Roland TB-303 bass line that became such an integral part of many electronic music genres. So, we created a rough emulation of the TB-303 in the patching environment of GameSynth. First, let’s check out how it sounds!

The Sound

Of course, it is not an exact emulation of the machine, but with a surprisingly low number of modules, we were able to mimic the original device close enough.

The TB-303’s architecture was relatively basic, which helped us:

  • We used an Oscillator module of Saw type as the generator (it can of course be set to Pulse, like on the 303).
  • Then, we connected its output to an EQ Filter set to Lowpass with a slope of 24db/octave.
  • The EQ Filter frequency and q inputs are controlled by an Envelope that simulates the envelope modulation of the machine.
  • We also added a Saturator of Cubic type, with only a bit of saturation to add that analogue touch to the sound.
  • At the end of the audio chain, an Envelope controlling a Gain module acts as the general amplitude envelope for a single note.

The Sequencer

To play a sequence of notes like the original, we added some new modules:

  • A Clock connected to two Arpeggiators controls both the amplitude and the pitch of the Oscillator.
  • The Arpeggiator connected to the amplitude is used to select which notes from the sequence we want to trigger.
  • The other Arpeggiator – connected to the pitch creates the melody.

By adjusting the two Arpeggiators’ steps, it is possible to generate various bass lines, while the Clock can be used to change the tempo of the whole sequence.

The Controls

In order to replicate some of the controls from the original synth – and perform the patch in real-time – we added several Meta Parameters. Therefore, although the sound generation was quite trivial, the control section of the patch uses more modules.

The Tempo Meta Parameter is connected directly to the Clock’s frequency, and the Cutoff Freq and Resonance Meta Parameters are connected to the EQ Filter’s frequency and q respectively.

The two last Meta Parameters, however, were a bit trickier to add as they affect parts of the patch that are already controlled. The Envelope Modulation (Env Mod) controls the amount of modulation on the filter, and the Accent – which makes the sound of the 303 so unique – adds emphasis on specific notes.

To achieve this, we used several Arithmetic modules (set to Multiplication or Addition) to mix and prioritize the control signals as intended, while another Arpeggiator module was used to select the accented notes. The Biquad Filters in the control chain are simply used to smooth the signal a bit.

So here it is, happy 303 day everybody, and thank you Roland for designing such an iconic machine! The patch is available below, so do not hesitate to share your comments or suggestions on our new Discord server.