Session 27

Quick Reference

The Basic Patch

The "home base" for all learning sessions. Adapted from Anu Kirk's Definitive Guide to Evolver (p.7-8). This is a minimal, neutral patch that lets you isolate and hear the effect of any single parameter change.

Save this to Program 128 in Bank 1 (and a backup copy elsewhere).

Why This Matters

Without a known starting state, you can't isolate what you're learning. When you turn a knob and hear a change, you need to know that change came from that knob and not some other parameter interaction. The basic patch is your lab bench.

Source: Anu Kirk Guide p.7 -- "The Basic Patch"

Complete Parameter Dump

Every parameter on the Evolver front panel, organized by section. Values sourced from Anu Kirk's basic patch table (p.7-8) and verified against the DSI Manual parameter definitions (p.14-26).

Global Parameters

Parameter	Value	Notes
Main Volume	75	Overall output level
Pot Mode	Relative	Recommended for learning -- changes are relative to stored values

Source: Anu Kirk Guide p.7, DSI Manual p.13

Oscillator 1 (Analog, Left Channel)

Parameter	Value	Notes
Frequency	C0	Base pitch, lowest practical range. C3 = middle C
Fine	0	No detuning (range: -50 to +50 cents)
Shape	Saw	Sawtooth wave -- rich harmonics, good for hearing filter changes
Level	50	Half volume (range: 0-100)
Glide	0	No portamento (range: 0-100, or Finger 02-100, or Keybd Off)

Oscillator 2 (Analog, Right Channel)

Parameter	Value	Notes
Frequency	C0	Same as Osc 1
Fine	0	No detuning
Shape	Saw	Sawtooth wave
Level	50	Half volume
Glide	0	No portamento

Analog Oscillator Shared Parameters

Parameter	Value	Notes
Sync 2->1	OFF	No hard sync (Osc 2 does not reset Osc 1)
Osc Slop	0	No random frequency drift (range: 0-5)

Oscillator 3 (Digital, Left Channel)

Parameter	Value	Notes
Frequency	C0	Base pitch
Fine	0	No detuning
Shape	1	Sine wave (first waveshape in Prophet-VS set)
Level	50	Half volume
Glide	0	No portamento
FM 4->3	0	No frequency modulation from Osc 4 (range: 0-100)
Ring Mod 4->3	0	No ring modulation from Osc 4 (range: 0-100)
Shape Seq	OFF	No waveshape sequencing

Oscillator 4 (Digital, Right Channel)

Parameter	Value	Notes
Frequency	C0	Base pitch
Fine	0	No detuning
Shape	1	Sine wave
Level	50	Half volume
Glide	0	No portamento
FM 3->4	0	No frequency modulation from Osc 3 (range: 0-100)
Ring Mod 3->4	0	No ring modulation from Osc 3 (range: 0-100)
Shape Seq	OFF	No waveshape sequencing

Noise

Parameter	Value	Notes
Volume	0	No noise mixed in (range: 0-100, feeds both channels equally)

Lowpass Filter (Analog, L+R in tandem)

Parameter	Value	Notes
Frequency	164	Wide open -- maximum cutoff, all harmonics pass through (range: 0-164)
Resonance	0	No resonance (range: 0-100, self-oscillates in 4-pole at high values)
2/4 Pole	2P	2-pole mode (-12dB/oct). 4-pole is -24dB/oct and can self-oscillate
Env Amount	0	No filter envelope modulation (range: -99 to +99)
Velocity	0	No velocity sensitivity on filter envelope
Key Amount	0	No keyboard tracking on filter cutoff (72 = 1 semitone/note)
Audio Mod	0	No audio-rate modulation from analog osc (range: 0-100)
Split	0	L/R filters locked together (range: 0-100, raises L / lowers R)

Filter Envelope (ENV 1)

Parameter	Value	Notes
Attack	0	Instant attack (range: 0-110)
Decay	0	No decay (range: 0-110)
Sustain	100	Full sustain -- filter stays open while key held (range: 0-100)
Release	0	Instant release (range: 0-110)

VCA (Amplifier)

Parameter	Value	Notes
Level	0	No base level -- sound only when envelope is active (range: 0-100)
Env Amount	100	Full envelope control of amplitude (range: 0-100)
Velocity	0	No velocity sensitivity on VCA envelope
Output Pan	St1	Full stereo (L fully left, R fully right). Options: St1, St2, St3, Mono, rSt1, rSt2, rSt3
Volume	100	Voice volume at maximum (range: 0-100)

VCA Envelope (ENV 2)

Parameter	Value	Notes
Attack	0	Instant attack (range: 0-110)
Decay	0	No decay (range: 0-110)
Sustain	100	Full sustain -- sound holds at full level while key pressed (range: 0-100)
Release	0	Instant release (range: 0-110)

Highpass Filter (Digital)

Parameter	Value	Notes
Frequency	0	No high-pass filtering (range: 0-99)

Tuned Feedback

Parameter	Value	Notes
Frequency	0	C0, lowest feedback pitch (range: 0-48, steps in semitones C0-C4)
Level	0	No feedback (range: 0-100, oscillates at high levels)
Grunge	OFF	No nasty feedback character

Distortion

Parameter	Value	Notes
Amount	0	No distortion (range: 0-99). Note: noise gate activates at any non-zero value

Output Hack

Parameter	Value	Notes
Amount	0	No bit-crushing (range: 0-14)

Delay (All 3 Taps)

Parameter	Value	Notes
Time 1	0	No delay on tap 1 (range: 0-150, or sync values)
Level 1	0	Tap 1 silent
Time 2	0	No delay on tap 2
Level 2	0	Tap 2 silent
Time 3	0	No delay on tap 3
Level 3	0	Tap 3 silent
Feedback 1	0	No delay self-feedback (range: 0-100)
Feedback 2	0	No delay-to-filter feedback (range: 0-100)

Envelope 3 (Mod Envelope)

Parameter	Value	Notes
Destination	OFF	No modulation target
Amount	0	No modulation amount (range: -99 to +99)
Velocity	0	No velocity sensitivity
Delay	0	No pre-attack delay (range: 0-100)
Attack	0	Instant attack (range: 0-110)
Decay	0	No decay (range: 0-110)
Sustain	0	Zero sustain (range: 0-100)
Release	0	Instant release (range: 0-110)

LFO 1 (Low Frequency Oscillator)

Parameter	Value	Notes
Frequency	0	Slowest rate (range: 0-150, or sync values)
Shape	Tri	Triangle wave (options: Tri, RevSaw, Saw, Square, Random)
Amount	0	No modulation (range: 0-100)
Destination	OFF	No modulation target
Key Sync	OFF	LFO free-runs (does not restart on key press)

LFO 2

Parameter	Value	Notes
Frequency	0	Slowest rate
Shape	Tri	Triangle wave
Amount	0	No modulation
Destination	OFF	No modulation target
Key Sync	OFF	Free-running

LFO 3

Parameter	Value	Notes
Frequency	0	Slowest rate
Shape	Tri	Triangle wave
Amount	0	No modulation
Destination	OFF	No modulation target
Key Sync	OFF	Free-running

LFO 4

Parameter	Value	Notes
Frequency	0	Slowest rate
Shape	Tri	Triangle wave
Amount	0	No modulation
Destination	OFF	No modulation target
Key Sync	OFF	Free-running

Modulation Slot 1

Parameter	Value	Notes
Source	OFF	No modulation source
Amount	0	No modulation amount (range: -99 to +99)
Destination	OFF	No modulation target

Modulation Slot 2

Parameter	Value	Notes
Source	OFF	No modulation source
Amount	0	No modulation amount
Destination	OFF	No modulation target

Modulation Slot 3

Parameter	Value	Notes
Source	OFF	No modulation source
Amount	0	No modulation amount
Destination	OFF	No modulation target

Modulation Slot 4

Parameter	Value	Notes
Source	OFF	No modulation source
Amount	0	No modulation amount
Destination	OFF	No modulation target

MIDI Controllers

Parameter	Value	Notes
Velocity Destination	OFF	No velocity routing
Velocity Amount	0	No velocity modulation
Mod Wheel Amount	0	No mod wheel modulation
Mod Wheel Destination	OFF	No mod wheel target
Pressure Amount	0	No aftertouch modulation
Pressure Destination	OFF	No aftertouch target
Breath Amount	0	No breath control modulation
Breath Destination	OFF	No breath target
Foot Controller Amount	0	No foot pedal modulation
Foot Controller Destination	OFF	No foot pedal target

Sequencer (All 4 Tracks)

Parameter	Value	Notes
Seq 1 Destination	OFF	No sequencer modulation target
Seq 2 Destination	OFF	No sequencer modulation target
Seq 3 Destination	OFF	No sequencer modulation target
Seq 4 Destination	OFF	No sequencer modulation target
All Step Values (1-16)	0	All 64 steps (4 tracks x 16 steps) set to 0

External Input

Parameter	Value	Notes
Volume	0	No external audio (range: 0-100)
Mode	St	Stereo mode (options: Stereo, Mono Left, Mono Right, L Control + R Audio)
Input Hack	0	No input bit-crushing (range: 0-14)
Input Peak Amount	0	No peak hold modulation
Input Peak Destination	OFF	No peak hold target
Env Follow Amount	0	No envelope follower modulation
Env Follow Destination	OFF	No envelope follower target

Miscellaneous Parameters

Parameter	Value	Notes
Env Shape	Exp	Exponential envelopes (more natural than Linear)
Key Off/Transpose	-24	Keyboard transposed down 2 octaves for best range
Pitch Wheel Range	0	No pitch bend
BPM	120	Default tempo
Clock Divide	8n	Eighth note division
Trigger Select	Seq or Key	Envelopes triggered by sequencer or keyboard
Key Mode	Poly Low Note	Low note priority (Poly for poly chain compatibility)

Source: Anu Kirk Guide p.7-8, DSI Manual p.14-26

What It Sounds Like

A plain, bright, sustained tone. Both analog oscillators playing sawtooth waves in stereo with the filter wide open and no modulation. Boring on purpose -- it's a canvas, not a painting.

Quick Test

After programming, play middle C. You should hear a bright, buzzy, sustained sawtooth tone in stereo. If you hear anything else -- modulation, filtering, echo, distortion -- something is still set wrong.

Parameter Count Summary

Section	Parameters
Global	2
Oscillators 1-4	26
Analog Shared (Sync, Slop)	2
Noise	1
Lowpass Filter	8
Filter Envelope (ENV 1)	4
VCA	5
VCA Envelope (ENV 2)	4
Highpass Filter	1
Tuned Feedback	3
Distortion	1
Output Hack	1
Delay (3 taps)	8
Envelope 3	8
LFOs 1-4	20
Mod Slots 1-4	12
MIDI Controllers	10
Sequencer	68 (4 destinations + 64 steps)
External Input	7
Misc Parameters	7
Total	~198

This session builds on Session #26 — complete it first for the best experience

Session 27: Bass Sounds -- Sub, Acid, and FM

25 min|advanced|patch

Session 27: Bass Sounds -- Sub, Acid, and FM

Objective: Build three distinct bass patches from scratch -- sub bass, acid bass, and FM bass -- using techniques from all previous modules, producing named patches with full parameter documentation.

If you only have 5 minutes

Load the basic patch. Set Osc 1 Shape = Saw, Level = 55, Osc 2 Shape = Pulse 50, Level = 50, Fine = +3. LPF Freq = 45, Resonance = 70, 4-Pole ON, Env Amount = 80, Decay = 45, Sustain = 5. Glide = 30. Instant acid bass.

Warm-Up (2 min)

Load your generative sequence patch from Session 26. Press START/STOP and listen for 30 seconds to the self-playing pattern. You have mastered every building block: oscillators, filters, modulation, effects, and sequencer. Now you combine them into specific sounds. Stop the sequence and load the basic patch.

From the basic patch:
- Osc 1 Shape = Saw, Level = 55, Frequency = C0
- Osc 2 Shape = Saw, Level = 50, Frequency = C0, Fine = +2 (very slight detuning for width)
- Osc 3 Level = 0, Osc 4 Level = 0
Filter settings -- almost closed to remove upper harmonics:
- LPF Frequency = 35, Resonance = 0, 4-Pole ON
- Key Amount = 72 (filter tracks keyboard)
- Env Amount = 25, ENV 1: Attack = 0, Decay = 40, Sustain = 60, Release = 15
VCA for tight bass envelope:
- ENV 2: Attack = 0, Decay = 30, Sustain = 80, Release = 10
Output: Pan = Mono (bass should be centered for mix compatibility)

Play notes in the C1-C3 range. You should hear a deep, round sub bass with a gentle filter pluck on attack
Add Osc Slop = 1 for subtle analog warmth

Save as "Sub Bass". This is your go-to low-end patch.

Recipe 2: Acid Bass (8 min)

Resonant filter sweep, glide between notes, aggressive character. The classic 303-inspired sound.

Load the basic patch fresh:
- Osc 1 Shape = Saw, Level = 55
- Osc 2 Shape = Pulse 50, Level = 50, Fine = +3
- Osc 3 Level = 0, Osc 4 Level = 0
- Osc Slop = 3
Acid filter -- high resonance, strong envelope sweep:
- LPF Frequency = 45, Resonance = 70, 4-Pole ON
- Env Amount = 80
- ENV 1: Attack = 0, Decay = 45, Sustain = 5, Release = 15
- Key Amount = 72
VCA -- punchy:
- ENV 2: Attack = 0, Decay = 35, Sustain = 70, Release = 12
Acid character:
- Glide (Osc 1 and 2) = 30 (fingered glide for slides between notes)
- Distortion = 15 (subtle edge)

Play legato notes in the C1-C2 range. You should hear the classic acid squelch: resonant filter sweep on each note, glide between held notes
For extra acid: add Velocity on filter = 40 -- harder playing opens the filter more
Try it with a sequence: Seq 1 Dest = OAF, program 36, 36, 48, 48, 43, oFF, 46, 36, Step 9 = rST, BPM = 130, Clock Divide = 16th

Save as "Acid Bass".

Recipe 3: FM Bass (8 min)

Metallic, punchy low end using FM between digital oscillators. Modern bass sound.

Load the basic patch fresh:
- Osc 1 Level = 0, Osc 2 Level = 0 (digital only)
- Osc 3 Shape = 1 (sine), Level = 55, Frequency = C0
- Osc 4 Shape = 1 (sine), Level = 0 (modulator, not heard directly), Frequency = C0
- FM 4->3 = 45 (Osc 4 modulates Osc 3's frequency)
Filter -- moderate, controlled:
- LPF Frequency = 55, Resonance = 20, 4-Pole ON
- Env Amount = 40
- ENV 1: Attack = 0, Decay = 50, Sustain = 15, Release = 15
- Key Amount = 72
VCA:
- ENV 2: Attack = 0, Decay = 35, Sustain = 65, Release = 15
FM envelope for punch -- the FM amount decreases over time for a metallic attack:
- ENV 3: Destination = FM4 (FM 4->3 Amount), Amount = 55, Attack = 0, Decay = 40, Sustain = 10, Release = 15

Play notes in the C1-C3 range. You should hear a metallic, complex bass that is punchy on the attack (high FM) and settles to a simpler tone (low FM) as the note sustains
Try different Osc 4 Frequency ratios: set Osc 4 to C1 (one octave up from Osc 3) for a different harmonic series. G0 creates a 3:2 ratio -- experiment with intervals
Add Distortion = 10 for extra grit

Save as "FM Bass".

Exploration (optional, hyperfocus days)

Combine Sub Bass with a sequenced acid pattern: use the sub bass as the oscillator sound but add acid filter settings
Add the delay from Session 19 to any bass patch for dubby echoes: Delay 1 Time = 2 Steps, Level = 35, Feedback 1 = 40, Feedback 2 = 25
Make a "Reese bass": two detuned saws (Osc 1 Fine = +8, Osc 2 Fine = -8) with LFO on filter cutoff

Output Checklist

Sub Bass patch saved -- deep, round, centered
Acid Bass patch saved -- resonant filter sweep, glide, punchy
FM Bass patch saved -- metallic, complex, envelope-shaped FM
Session logged in Obsidian daily note

Key Takeaways

Sub bass uses closed filter and minimal processing for a clean low end; mono output is essential for mix compatibility
Acid bass depends on three elements: high resonance, strong filter envelope, and glide -- the interplay between these creates the characteristic squelch
FM bass uses envelope-controlled FM amount to create a metallic attack that decays to a simpler tone -- the FM ratio (oscillator frequency relationship) determines the harmonic character

Next Session Preview

Session 28 creates three lead patches -- sync lead, FM lead, and filtered lead. These are performance-oriented sounds with expression mappings for mod wheel and velocity.