Session 19: Digital Delay -- Time, Taps, and Sync

Objective: Use the Evolver's 3-tap digital delay for rhythmic echo, ambient space, and sound design through multi-tap configuration, tempo sync, and feedback paths.

Warm-Up (2 min)

Load your evolving texture patch from Session 18. Play a sustained chord and listen to the modulation layers you built. That complexity came from stacking modulation sources. Today you enter the effects domain -- delay, feedback, and distortion -- where post-processing transforms raw synthesis into finished sounds. Load the basic patch.

Setup

From the basic patch:

• Set Osc 3 Level to 0 and Osc 4 Level to 0 (analog oscillators only for clarity)
• Set ENV 2 (VCA): Decay = 60, Sustain = 0, Release = 25 (short percussive notes so echoes are distinct)
• Verify LPF Frequency = 164 (wide open)

This gives a bright, short pluck so every delay tap is clearly audible.

Exercises

Exercise 1: Single-Tap Delay Basics (5 min)

The Evolver's delay sums L+R to mono input, provides up to 1 second at 16-bit 48kHz, and outputs to both channels equally (DSI Manual p.20).

1. Press Delay 1 to select it
2. Set Delay 1 Time to 144 (long delay, close to 1 second)
3. Set Delay 1 Level to 75

4. Play a short note -- you should hear a clear echo roughly 1 second later. This is a basic single-tap delay
5. Change Delay 1 Time to 110 -- shorter delay, about 500ms. Play staccato notes and hear the slapback echo
6. Add Feedback 1 = 50 -- play a note and hear it repeat multiple times, each echo quieter than the last. Feedback routes the delay output back to the delay input (DSI Manual p.20)
7. Try Feedback 1 = 85 -- echoes barely decay. At 100 they would sustain indefinitely and eventually distort

Key insight: Time sets delay duration (0-150 for free, past 150 for sync). Level sets first echo volume. Feedback 1 sets number of repeats.

Exercise 2: Tempo-Synced Delay (5 min)

Musical delay locks to your tempo. Delay time values past 150 provide synchronized times (DSI Manual p.20).

1. Set Feedback 1 back to 40
2. Scroll Delay 1 Time past 150 until you see 1 Step -- the delay now equals one sequencer step in length
3. Press START/STOP to start the sequencer (you do not need sequences programmed -- you just need the clock running)
4. Play a rhythmic pattern of short notes -- the echoes lock perfectly to the beat
5. Change to 2 Steps -- classic echo feel, wider spacing
6. Change to 4 Steps -- spacious ambient echo
7. Try 1/2 Step -- tight, doubled rhythm. The delay fills in between your notes
8. Stop the sequencer when done

Sync settings depend on BPM and Clock Divide. At 120 BPM / 8th notes, 1 Step = one eighth note.

Exercise 3: Multi-Tap Delay (8 min)

Three independent taps can create complex rhythmic delay patterns (Anu Kirk p.60).

1. Set Delay 1 Time to 110, Level to 65
2. Press Delay 2 to select it. Set Delay 2 Time to 125, Level to 50
3. Press Delay 3 to select it. Set Delay 3 Time to 140, Level to 35
4. Set Feedback 1 to 30

5. Play a short note -- you should hear three distinct echoes at different time intervals, creating a rhythmic cascade. The levels decrease so the pattern fades naturally
6. Now change to synced times for a musical pattern: Delay 1 Time = 1 Step, Delay 2 Time = 2 Steps, Delay 3 Time = 4 Steps
7. Play notes against the sequencer clock -- the three taps create a dotted rhythm pattern

Important: When using all 3 taps, keep individual levels moderate (35-70 each) to prevent overload distortion from the summed signals (DSI Manual p.20).

Exercise 4: Feedback Paths and Sound Design (5 min)

Feedback 2 routes delay output back to the analog filter input, enabling extreme effects (DSI Manual p.20).

1. Keep the multi-tap setup from Exercise 3
2. Lower LPF Frequency to 80, set Resonance to 50
3. Set Feedback 2 to 35 (Feedback 1 still at 30)
4. Play a note -- the echoes now pass through the filter each time they repeat, getting progressively darker and more resonant. This is a fundamentally different character from Feedback 1
5. Now try very short delay times for metallic effects: Delay 1 Time = 10, Level = 60, Delay 2 Time = 15, Level = 55, Delay 3 Time = 20, Level = 50
6. Set Feedback 1 to 55, Feedback 2 to 0
7. Play a note -- this is not an echo anymore. The short delays create comb filtering, adding a metallic, resonant character to the sound

Save this patch as your "Rhythmic Delay" patch (use the synced multi-tap version from step 6 of Exercise 3).

Exploration (optional, hyperfocus days)

• Route an LFO to Delay 1 Time (LFO Dest = DT1): at short delay times, this creates chorus and flange effects (Anu Kirk p.61-63). Try LFO Freq = 25, Amount = 15, Shape = Tri with Delay 1 Time = 85
• Set Feedback 1 to 90 and play a single note -- listen to the delay build up and self-oscillate
• Load your sync lead from Session 05 and add the synced multi-tap delay. A solo sound becomes a rhythmic event

Output Checklist

• Rhythmic delay patch saved with tempo-synced multi-tap configuration
• Understand Time / Level / Feedback 1 / Feedback 2 and what each controls
• Heard multi-tap delay creating rhythmic patterns at different sync values
• Session logged in Obsidian daily note

Key Takeaways

• The Evolver's delay has three independent taps, each with separate time and level -- this allows complex rhythmic patterns from a single note
• Tempo-synced delay times (past value 150) lock echoes to the sequencer clock, making delay musical rather than random
• Feedback 2 routes echoes through the analog filter, progressively darkening repeats -- a fundamentally different sound from standard Feedback 1

Next Session Preview

Session 20 explores the Evolver's tuned feedback and Karplus-Strong synthesis -- using delay and feedback to create plucked string, marimba, and physical modeling sounds. This is one of the Evolver's most unique capabilities.