Vocal Chop Rack

A vocal chop rack that takes one vocal phrase and gives you three ways to play it from a keyboard: a Simpler in Slice mode where each key is a transient chop, a Sampler chain that pitches the whole phrase chromatically with formant correction, and a sustained Vocoder chain that turns the vocal into a playable chord pad. Auto Shift does the pitch correction and harmonization, Shifter handles formant moves, and the six macros (Formant, Pitch, Chop Length, Space, Robot, Tape) are everything you need to go from UK garage skip-chop to trap pitched hook to hyperpop robot. Vocals sit between 150 Hz and 8 kHz; the rack cuts everything else so it never argues with bass or hats.

Layout

How it's built

1. Prepare the source: a dry vocal phrase, 2–4 bars, warped to the set tempo, consolidated, normalised to −3 dBFS. Put it on an audio track named "Vocal Audio" (needed later for the Vocoder modulator) and keep a copy in the User Library.
2. New MIDI track, empty Instrument Rack, three chains.
3. Chain "Slice Chops" (Simpler, Slice): drop the phrase into Simpler, mode Slice, Slice by Transient, sensitivity 60%, playback Mono, Trigger mode (not Gate), Warp off. Slices land on C1 upward, one key per chop. Fade out 20 ms to kill clicks. Amp envelope A 0 / D 400 ms / S 0 / R 30 ms so each key is a short chop; Chop Length will stretch this.
4. Add Shifter after Simpler: Pitch mode, pitch 0 st, formant 0, Window 40 ms, Tone 60%. Then EQ Eight HP 150 Hz (12 dB), LP 10 kHz.
5. Key zone C1–C4 (covers up to 36 slices). Chain volume −2 dB.
6. Chain "Pitched Phrase" (Sampler): drop the phrase into Sampler, root C3, one zone covering C4–C7, Warp mode Complex Pro with Formants 0% (in Sampler’s zone editor enable warping for the sample). Sustain loop over the whole phrase, loop mode Forward, crossfade 20 ms. Amp env A 5 ms / D 2 s / S 0.8 / R 200 ms. Filter off.
7. After Sampler: Auto Shift. Scale: match the song (C minor here), Amount 85%, Speed 50 ms, Humanize 10%, Vibrato 0. Then Shifter in Formant tracking mode (formant follows the played pitch) and EQ Eight HP 150 Hz.
8. Key zone C4–C7 so chops and phrase do not overlap. Chain volume −3 dB.
9. Chain "Vocoder Pad" (Simpler + Vocoder): Simpler Classic mode loading a sustained saw-ish sample (a bounced 4-voice Drift saw chord works; any bright sustained tone is a good carrier). Loop on, Warp Complex, amp A 150 ms / D 1 s / S 1 / R 600 ms, 8 voices. Then Vocoder: Carrier set to the device input (the Simpler), Modulator set to External, choosing "Vocal Audio" post-FX as the source. Bands 24, Range 150 Hz–8 kHz, Formant 0, Release 60 ms, Enhance on, Unvoiced 20% so consonants come through. Then Hybrid Reverb, Quartz, 35%, decay 2.5 s.
10. Key zone C2–C7, velocity zone 1–90: soft playing gives the vocoder pad, harder playing above 90 on the same keys gives only the chop or phrase chains. Chain volume −8 dB.
11. Wrap the rack with post effects: Vinyl Distortion (Tracing 0, Pinch 0, Crackle 0 by default), Redux (16 bit, downsample 1, Soft on), Echo (1/8 stereo, feedback 30%, HP 300 Hz, dry/wet 0). Select all and Cmd+G to create the outer rack; map macros on the outer rack.
12. Formant: Shifter formant on the chop chain −12 → +12 st, Sampler formant shift −12 → +12 (Complex Pro Formants parameter in the zone), Vocoder formant −6 → +6. Centre of the knob is neutral; store that as the default so a reset sounds natural.
13. Pitch: Shifter pitch on the chops −12 → +12 st, Sampler transpose −12 → +12 st. Not mapped on the Vocoder chain, since the vocoder pitch is whatever you play.
14. Chop Length: Simpler fade out 5 → 400 ms, Simpler amp decay 40 → 2000 ms, amp sustain 0 → 1. At minimum you get staccato 40 ms stutters; at maximum each slice plays to its end.
15. Space: Hybrid Reverb dry/wet 0 → 60% (Vocoder chain) and Echo dry/wet 0 → 35% (post-rack).
16. Robot: Auto Shift amount 0 → 100%, Auto Shift speed 200 → 2 ms (inverted: faster correction = harder robot), Vocoder Pad chain volume −inf → −6 dB so the vocoder joins in as the knob rises.
17. Tape: Vinyl Distortion tracing 0 → 40%, Redux bit depth 16 → 8, Redux downsample 1 → 8, EQ Eight LP on the chop chain 10 kHz → 4 kHz. Four parameters, one lo-fi knob.
18. Macro Variations: "Garage" (Formant 64, Pitch 64, Chop Length 20, Space 25, Robot 0, Tape 15), "Trap hook" (Formant 50, Pitch 40, Chop Length 90, Space 40, Robot 30, Tape 25), "Hyperpop" (Formant 100, Pitch 90, Chop Length 60, Space 50, Robot 100, Tape 10). Exclude Pitch from randomization so the hook stays in key; the rest randomize well.

Macro map

Signal flow notes

Slice Chops chain

Pitched Phrase chain

Complex Pro with the Formants parameter is what keeps a vocal from chipmunking when you play it a fifth up. Auto Shift afterwards snaps whatever the warp produced to the scale, and with Speed at 2 ms it becomes the hard-tune effect; with Amount at 85% and 50 ms it just tidies.

Vocoder Pad chain

Variations

• UK garage / 2-step: slice by 1/16 instead of transient, Chop Length 15, Pitch +5 default, Tape 20, add a Beat Repeat (1/16, Chance 20%) after the Echo. See UK garage.
• Trap / drill: Pitch −5 to −7, Formant −4, Robot 40, Chop Length 90, Space 50, add Auto Pan-Tremolo (12.3) in Tremolo mode at 1/8 for the stuttered tail. See trap and drill.
• Hyperpop: Formant +10, Robot 100, Pitch +12, Tape 30, Chop Length 50, Auto Shift Vibrato 30% at 6 Hz. See hyperpop.
• Dubstep / 140: replace Shifter on the chop chain with a Roar (Multiband, Fold on the mid band), Chop Length 10, add a Grain Delay at 1/16 with pitch −12 on 20% wet. See dubstep.
• Lo-fi hip-hop: Tape 80, Formant −2, Chop Length 60, Space 30, Robot 0, Sampler Warp mode Texture for the smeared version. See lo-fi hip-hop.

Performance notes

• Push: Push’s pad grid in chromatic layout puts slices C1–C4 on the lower rows and the phrase keys above; use the Slice mode’s pad layout for finger drumming the chops. Macros: Chop Length and Formant on encoders 1–2, Robot and Tape on 5–6.
• Automation vs macro: automate Pitch per section (it is musical, not a performance gesture); play Chop Length, Formant and Space. Tape is a section-level setting; automate it.
• Latency: Shifter and Vocoder both add latency. Keep "Reduced Latency When Monitoring" on when playing live; expect 10–30 ms total.
• CPU: Vocoder with 24 bands is the main cost (around 5% of a core); Complex Pro warping in Sampler is the second. Freeze the track between sections in a long set.
• Re-sourcing: swap the vocal by replacing the sample in all three Simplers/Samplers (hot-swap). Re-slice after replacing; the slice map does not transfer.

Related

• Voice and vocals · Glitch and IDM sounds
• Sampler, Simpler and Drum Rack · Effects overview
• Spectral processing · Resampling workflow
• Resampling rack · Texture rack
• UK garage · Trap · Hyperpop