Routing to Multiple Synths

Layer sounds, split keyboard zones, or create complex multi-timbral setups by routing one MIDI source to multiple destinations with independent transforms.

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What You'll Learn

• Layering - Stack multiple synths for richer sounds
• Splitting - Divide keyboard into zones for different synths
• Multi-timbral - Send different channels to different synths
• Performance tips - Optimize routing for live use
• Advanced techniques - 3+ synth routing, parallel processing

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Why Route to Multiple Synths?

Layering

Combine sounds for thickness and complexity:

• Lead + Pad - Bright lead with warm pad underneath
• Piano + Strings - Classic orchestral layer
• Bass + Sub - Main bass + sub-bass reinforcement
• Drums + Percussion - Layered rhythm elements

Benefits:

• Richer, more complex timbres
• Fill frequency spectrum (highs + lows)
• Add movement (one synth static, one modulated)

Splitting

Divide keyboard into zones:

• Bass + Lead - Left hand bass (C1-C3), right hand lead (C4-C6)
• Drums + Keys - Low keys drums, mid/high keys melodic
• Multi-zone - 3+ zones for complex arrangements

Benefits:

• Play multiple parts simultaneously
• Reduce need for additional keyboards
• Self-contained performance rig

Multi-Timbral

Separate MIDI channels to different synths:

• Channel 1 → Synth A (lead)
• Channel 2 → Synth B (pad)
• Channel 10 → Synth C (drums)

Benefits:

• DAW sequencing to multiple synths
• Complex arrangements from one controller
• MIDI file playback to hardware

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Basic Layering Setup

Scenario: Piano + Strings Layer

Hardware:

• MIDI keyboard (source)
• Soft synth (piano sound)
• Hardware synth (strings sound)

Goal: Every note plays piano AND strings simultaneously.

Step-by-Step

1. Create first route:

1. Sources → Select your MIDI keyboard
2. Destinations → Select soft synth (piano)
3. Route created → All notes play piano

2. Create second route:

1. Sources → Select your MIDI keyboard (same source!)
2. Destinations → Select hardware synth (strings)
3. Second route created → All notes now play BOTH piano and strings

3. Balance the layer:

Add transforms to shape each layer:

Piano route (bright, percussive):

• No transform needed (full velocity range)
• Or Velocity Add (+10) to emphasize attack

Strings route (soft, smooth):

• Velocity Scale (0.7) - Reduce to 70% for gentler strings
• Or Velocity Clamp (1-90) - Cap velocity to avoid harsh attacks

4. Test:

• Play keyboard softly → Piano + gentle strings
• Play keyboard hard → Bright piano + moderate strings (not harsh)

5. Save:

• Settings → Profiles → Create New Profile → "Piano Strings Layer"
• Instantly recall this exact setup later

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Keyboard Split Setup

Scenario: Bass (Left Hand) + Lead (Right Hand)

Hardware:

• 61-key MIDI keyboard
• Bass synth
• Lead synth

Goal: C1-B2 (left hand) → bass, C3-C6 (right hand) → lead.

Step-by-Step

1. Create bass route (left hand):

1. Sources → MIDI keyboard
2. Destinations → Bass synth
3. Add Transform → NeuroScript
4. Script:

# Keep only notes in bass range (C1-B2 = 24-47)
keep note where note in 24..47

2. Create lead route (right hand):

1. Sources → MIDI keyboard (same source)
2. Destinations → Lead synth
3. Add Transform → NeuroScript
4. Script:

# Keep only notes in lead range (C3-C6 = 48-84)
keep note where note in 48..84

3. Optional: Transpose bass down:

Bass synth may sound better one octave lower:

Bass route NeuroScript:

keep note where note in 24..47
when type == note : {
  octave(-1)  # Down one octave
  send
}

4. Optional: Add crossfade zone:

Create overlap where both synths play:

Bass route (extend range to C3):

keep note where note in 24..48  # Include C3

Lead route (extend range to B2):

keep note where note in 47..84  # Include B2

Result: B2-C3 plays BOTH bass and lead (smooth transition).

5. Test:

• Play C2 → Bass only
• Play B2-C3 → Bass + lead (crossfade)
• Play C4 → Lead only

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Three-Synth Layer

Scenario: Sub Bass + Bass + Lead

Hardware:

• MIDI keyboard
• Sub bass synth (sine wave, deep)
• Bass synth (rich harmonics)
• Lead synth (bright, cutting)

Goal: Full-range layer with frequency separation.

Routing

Route 1: Sub Bass (C1-B1, sine wave):

# Sub bass only on very low notes
keep note where note in 24..35  # C1-B1

# Fixed low velocity (sine waves don't need dynamics)
when type == note : {
  velFixed(80)
  send
}

Route 2: Bass (C2-B3, rich tone):

# Main bass range
keep note where note in 36..59  # C2-B3

# Full velocity response

Route 3: Lead (C4-C6, bright):

# Lead range
keep note where note in 60..84  # C4-C6

# Boost velocity for emphasis
when type == note : {
  velAdd(+10)
  send
}

Frequency Separation

Range	Synth	Role
C1-B1 (24-35)	Sub Bass	Low-end foundation
C2-B3 (36-59)	Bass	Main harmonic content
C4-C6 (60-84)	Lead	Melodic lead lines

No overlap = clean frequency separation (no masking).

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Multi-Timbral Routing (DAW to Hardware)

Scenario: DAW Sequencer → Multiple Hardware Synths

Setup:

• DAW (Logic Pro, Ableton Live, etc.)
• IAC Driver (macOS) or Network MIDI
• 3 hardware synths (Lead, Pad, Drums)

Goal: DAW sends Ch1 → Lead, Ch2 → Pad, Ch10 → Drums.

Routing

Route 1: Channel 1 → Lead Synth:

# Only pass Channel 1
keep where ch == 1

Route 2: Channel 2 → Pad Synth:

# Only pass Channel 2
keep where ch == 2

Route 3: Channel 10 → Drum Synth:

# Only pass Channel 10 (GM drums)
keep where ch == 10

In DAW:

1. Track 1 (Lead) → MIDI Out Ch1 → IAC Driver
2. Track 2 (Pad) → MIDI Out Ch2 → IAC Driver
3. Track 3 (Drums) → MIDI Out Ch10 → IAC Driver

In Neurode MIDI:

1. Source: IAC Driver
2. Routes: 3 routes (one per channel)
3. Destinations: Lead, Pad, Drums (hardware)

Result: DAW sequences all three synths independently.

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Advanced: Parallel Processing

Scenario: Send Same Notes to 3 Effects Processors

Setup:

• MIDI keyboard
• Main synth (dry)
• Effect Processor 1 (reverb)
• Effect Processor 2 (delay)

Goal: Dry signal + 2 independent wet signals (parallel effects).

Routing

Route 1: Dry Signal (no transform):

1. Source: MIDI keyboard
2. Destination: Main synth
3. Transform: None

Route 2: Reverb Send:

1. Source: MIDI keyboard
2. Destination: Effect Processor 1 (reverb)
3. Transform:

# Reduce velocity for subtle reverb
when type == note : {
  velScale(0.5)  # 50% velocity
  send
}

Route 3: Delay Send:

1. Source: MIDI keyboard
2. Destination: Effect Processor 2 (delay)
3. Transform:

# Even lower velocity for delay tail
when type == note : {
  velScale(0.3)  # 30% velocity
  send
}

Mixing:

• Dry: Full volume at synth output
• Reverb: Mix to taste (effect processor output)
• Delay: Mix to taste (effect processor output)

Result: Parallel processing with independent wet/dry balance.

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Troubleshooting

Both Synths Play Too Loud

Problem: Layering two synths results in clipping or overwhelming volume.

Solutions:

1. Reduce velocity on one or both routes:

when type == note : {
  velScale(0.7)  # 70% velocity
  send
}

2. Lower synth output levels (hardware/software mixer)
3. Use velocity split: One synth for soft notes, one for hard notes

# Synth A: Soft notes only
keep note where vel < 64

# Synth B: Hard notes only
keep note where vel >= 64

Split Point Not Clean

Problem: Notes around split point (e.g., C3) sometimes trigger both synths.

Solutions:

1. Use inclusive ranges to avoid gaps:

# Bass: C1-B2 (24-47)
keep note where note <= 47

# Lead: C3-C6 (48-84)
keep note where note >= 48

2. Add overlap for smooth transition:

# Bass: C1-C3 (24-48), includes C3
keep note where note <= 48

# Lead: B2-C6 (47-84), includes B2
keep note where note >= 47

Result: B2-C3 crossfade zone (both synths play).

MIDI Delays/Latency

Problem: Multiple routes cause noticeable delay between synths.

Solutions:

1. Use USB MIDI instead of Bluetooth (lower latency)
2. Reduce route complexity (fewer transforms = faster processing)
3. Disable visualizer (Settings → Performance → Visualizer OFF)
4. Close background apps (free CPU for MIDI processing)

Expected latency:

• USB MIDI: <1ms (imperceptible)
• Bluetooth MIDI: 10-30ms (noticeable phasing)
• Network MIDI: 5-15ms (acceptable)

Synth Doesn't Receive MIDI

Problem: Route created but destination synth is silent.

Diagnosis:

1. Check Activity Monitor - Is destination receiving messages?
2. Check route enabled - Green indicator in routing matrix?
3. Check transform errors - Route status shows "OK" or error?
4. Check synth settings - MIDI input enabled, correct channel?

Solutions:

• Enable route (tap route, toggle ON)
• Fix transform errors (view Route Status, fix script syntax)
• Verify synth MIDI settings (check manual for MIDI setup)

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Performance Tips

Optimize for CPU

Minimize route complexity:

• ❌ Avoid: Complex NeuroScript on every route (high CPU)
• ✅ Prefer: Simple filters (keep note where ch == 1)
• ✅ Prefer: Built-in transforms (faster than scripts)

Disable unused features:

• Settings → Performance → Visualizer OFF (saves CPU)
• Settings → Performance → AI Engine OFF (significant savings)
• Settings → Performance → Background Routing ON (keeps MIDI flowing)

Reduce MIDI Congestion

Limit message rate:

# Drop high-rate CC messages
drop cc where cc in 64..127

Expected message rates:

• Notes only: 10-50 msg/sec (low)
• Notes + CC: 50-150 msg/sec (moderate)
• Notes + CC + Clock: 150-300 msg/sec (high)

Warning: >300 msg/sec may cause buffer overflow (dropped messages).

Use Profiles for Instant Recall

Create profiles for each multi-synth setup:

1. Configure routing for Scenario A (e.g., "Piano Strings")
2. Save profile (Settings → Profiles → Create New)
3. Repeat for Scenario B (e.g., "Bass Lead Split")
4. Switch instantly during performance (Settings → Profiles → Select)

Benefits:

• No manual reconfiguration between songs
• Reliable (same exact routing every time)
• Fast (1-2 second switch time)

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Common Multi-Synth Scenarios

1. Studio Recording (Piano + Pad)

Goal: Rich, lush sound for ballad recording.

Routing:

• Piano route: Full velocity, no transform
• Pad route: velScale(0.6), slight transpose (+7 semitones for harmonic richness)

Mix: 70% piano, 30% pad (adjust in DAW).

2. Live Performance (Bass + Lead Split)

Goal: Self-contained rig, no additional keyboards needed.

Routing:

• Bass route: keep note where note <= 48, octave(-1)
• Lead route: keep note where note >= 49, velAdd(+15) for emphasis

Profile: "Live Rig A" (instant recall).

3. Electronic Production (Sub + Bass + Lead)

Goal: Full-spectrum sound design.

Routing:

• Sub route: keep note where note in 24..35, velFixed(90)
• Bass route: keep note where note in 36..59
• Lead route: keep note where note >= 60, velAdd(+10)

Result: Tight, punchy electronic track.

4. DAW Integration (Multi-Timbral)

Goal: Sequence 3 hardware synths from DAW.

Routing:

• Source: IAC Driver (macOS) or Network MIDI
• 3 routes with channel filters (keep where ch == 1, ch == 2, ch == 10)
• Destinations: Lead, Pad, Drums (hardware)

Workflow: Compose in DAW → Render hardware audio → Final mix.

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Related Topics

• Keyboard Split Guide - Detailed split techniques
• NeuroScript Guide - Transform scripting reference
• Profiles - Save and recall multi-synth setups
• Routing Concepts - Understanding MIDI routing architecture

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Best Practices

Start Simple

Build complexity gradually:

1. First: Single layer (2 synths, no transforms)
2. Then: Add velocity scaling
3. Then: Add keyboard split
4. Finally: Complex multi-synth (3+ synths, advanced transforms)

Early testing prevents cascading issues.

Test Each Route Independently

Before combining:

1. Create Route 1 (keyboard → synth A)
2. Test - Verify synth A plays correctly
3. Create Route 2 (keyboard → synth B)
4. Test - Verify synth B plays correctly
5. Enable both - Now verify layer works

Isolated testing identifies issues faster.

Document Your Setups

Add notes to profiles:

Profile: "Piano Strings Layer"
- Piano: No transform, full velocity
- Strings: velScale(0.7), softer layer
- Use: Ballads, slow songs

Benefits:

• Remember intent when returning months later
• Share setups with collaborators
• Troubleshoot faster (know expected behavior)

Use Consistent Channel Assignments

Standardize channels across setups:

• Ch 1 = Lead
• Ch 2 = Pad
• Ch 10 = Drums
• Ch 16 = Aux/FX

Consistency reduces cognitive load during live performance.