Electronic sound production

Synthesis: building and shaping a sound

Instructor preparation

Have Vital installed and a REAPER instrument track receiving MIDI. Use one oscillator, no effects, and a comfortable monitoring level.
Prepare a pluck and a pad from the same waveform, pitch, and filter setting. Change only the amplitude envelope. Match their perceived loudness as closely as practical.
Open the linked Ableton exercises before class. If unavailable, demonstrate the same controls in Vital; students can predict and sketch on paper while a partner or instructor operates the synth.

Suggested pacing across the scheduled meetings

October 28: beatmaking project review; synthesis has not started.
October 30: after the 20-minute Project 4 checkpoint, begin with the opening comparison, signal path, waveforms, and filter prediction. Introduce envelopes and begin the guided Vital task as time permits. Resume at the stopping point Monday; do not rush the deck or require Roulette today.
History and synthesis-method slides follow the exit check as optional reference. Use a short excerpt in a later lesson or if time permits. Do not play every video in the core lesson.
November 2: after the ear-training drill and beatmaking presentations, continue the synthesis introduction at the class’s stopping point. Students install Vital for homework before Wednesday.
November 4: check installations and MIDI input, then give a short pluck demonstration using the guided steps below. Walk through instructor-created presets, comparing their musical roles and the oscillator, filter, and amplitude-envelope choices behind them. Let students try the pluck and save a practice patch; extend it into a pad if time permits. These are practice patches, not a new graded submission. Keep the focus on basic controls; modulation begins Friday, November 6.
Roulette and the fuller Vital introduction are optional extensions once students are comfortable with the basic controls.

Same source, different articulation

Listen to a pluck and a pad on the same note.

What changes at the beginning and end?
Which control might explain the difference?

What you will be able to do

Identify the oscillator, filter, and amplifier by their jobs.
Predict a change in brightness or articulation.
Save a pluck and a pad, then explain two choices.

The audio path

Oscillator → Filter → Amplifier → Output

Oscillator: generates the raw sound.
Filter: shapes its frequency content.
Amplifier: controls its level.

Oscillators: pitch and waveform

Frequency sets the repetition rate and pitch. Waveform changes the harmonic content and timbre.

Explore oscillators

Basic waveforms

Basic periodic waveforms for comparing their cycle shapes

Predict, then listen: which sounds smoother, sine or saw?

Filters: changing brightness

A low-pass filter attenuates high frequencies.

Explore filters

Hold a saw note. Predict what lowering cutoff will do, then try it.

Filter responses

Frequency-response diagrams comparing filter types

Which response would reduce a saw’s high-frequency buzz?

Check: pitch or brightness?

A held note becomes darker; its MIDI note stays the same.

Which is the likely change?

Oscillator tuning
Low-pass cutoff

Explain what you expect to hear if tuning changes instead.

Amplifier and envelope

The amplifier changes audio level. The envelope controls how that level changes over time.

MIDI note-on starts the envelope. Note-off starts its release.

ADSR: time and level

ADSR amplitude envelope showing attack, decay, sustain level, and release after note-off

Attack, decay, release: time. Sustain: level.

Predict the articulation

Three ADSR settings and their envelope shapes: sharp attack, sudden release, and a plucked shape

Which shape keeps fading while you hold the key? Why?

Guided Vital patch: pluck

Right-click the preset name → Initialize Preset. Use one saw oscillator, one unison voice, no effects.
Enable Filter 1 and its OSC1 input. Use low-pass, cutoff about 2 kHz, low resonance.
In Env 1: attack 5 ms, decay 250 ms, sustain 0%, release 100 ms. Delay and hold: zero.
Save as YourName_Pluck_v1.

Allow about 7 minutes of the 15-minute patch task. Demonstrate each step and let students follow. First verify MIDI input and sound, then filter routing. Confirm that Oscillator 1’s routing selector reads Filter 1. Choose Analog: 12dB or Analog: 24dB and check that the blend control is at the low-pass end, with the response graph sloping down toward the highs. Keep the patch simple; wavetable morphing and additional unison voices come later. Show the save icon beside the preset name and reload the saved preset to verify it.

Approximate starting values: attack 5 ms, decay 250 ms, sustain 0%, release 100 ms. These are starting points, not assessed targets. Hold a note to check that it fades while the key stays down. Listen for clicks and soften the attack if necessary. Keep output at a comfortable level.

If setup fails, use the Ableton Synth Playground or work with a partner. Record the settings or a sketch so the student can rebuild the patch in Vital later. A Playground sketch does not replace a saved Vital preset for Project 5.

Your turn: pluck to pad

Keep the oscillator and filter unchanged.

In Env 1, try attack 400 ms, sustain 70%, release 800 ms. Leave decay at 250 ms.
Hold a note, then release it. Compare with the pluck.
Save as YourName_Pad_v1 and explain two changes to a partner.

Modulation: source and destination

A source changes a destination parameter.

Envelope → amplifier gain: note articulation. LFO → filter cutoff: repeating brightness change.

Explore repeating change

Exit check

Play your pluck and pad for a partner.

Trace the audio path and explain two envelope choices.
Predict a cutoff change, then test it.
Confirm that both presets are saved.

Optional history and reference

Different instruments offer different ways to shape sound.

Wendy Carlos and the Moog

Listen for a change in source, brightness, or articulation.

Buchla: shaping the source

What changes in the tone while a sound continues?

Yamaha DX7: another approach

Describe the attack and how brightness changes afterward.

Building a trumpet-like tone

Listen to a recorded note’s attack and sustained tone.
Inspect its harmonics and their relative levels.
Combine sine oscillators, then shape their levels over time.

Synthesis methods: reference

Subtractive: filter a harmonically rich source.
Additive: combine simpler components.
FM: use oscillators to modulate other oscillators.
Wavetable: select or scan waveform frames.

Further exploration

Open the Synth Playground

Choose one sound to change. Predict, adjust one control, and explain what you hear.