1 TubeSynth
As a basis for our Acid bed, we use the TubeSynth and load the Init preset. As the sound source, we only use Oscillator 2 and the SUB OSC, so we turn both up in the mixer the others to zero. Of course, we then set the filter SLOPE to an authentic 18 dB/Oct, increase RESO(nance) quite a bit, and set ENV to 55%.

2 Filter settings
For the Filter Envelope, a short 187 ms DEC(ay) is suitable, whereas for the Amp Envelope only SUS(tain) 100% and REL(ease) 1.00 ms are relevant. In the Setup tab, we set POLYPHONY to Legato and - importantly - GLIDE TIME to around 100 ms. This makes the typical glides of the 303 possible when you strike a note but still hold the previous one.

3 Pattern
With the sound, we have checked off one of three important factors for Acid. Factor two is also important: the pattern. Program any sequence over the length of a bar and include some overlap of notes, then give full velocity to only some notes, which simulates the Accent parameter.

4 Automation
Once you are satisfied with the pattern, duplicate the length of the SEQUENCE to a minimum of 16 bars and switch the Global Automation to Write Mode. Now we come to factor three: Any Acid Patterns would be boring if the sound always stays the same; therefore, it‘s time for movement in the game and we record it as automation.

5 Aciiiiid!
Start playback and, on the one hand, slowly move the Filter ENV control to build up voltage and combine this now and then with changes in the CUTOFF. You can also vary the resonance, but the sound quickly loses authenticity if there is too little resonance; this is where we reach the limits of what is technically possible.

6 Second bassline
Nonetheless, the following applies: Just try it out! Also important is the delay, which you should definitely activate. In our project, we record a pattern with base note F#1 and combine the track with a second TubeSynth with comparable settings, only without delay and with square instead of sawtooth. This version adds the subbass on F#0.
