Beat-Synchronized Effects

Learn to create lighting that follows the rhythm of your music.

Goal

Create effects that:

• Pulse on each beat
• Sync to musical phrases (4, 8, 16 beats)
• React to tap tempo changes

Time: 20 minutes

Understanding Beat Sync

Spectralite's beat system:

• Beat - The basic rhythmic unit
• Bar - 4 beats (in 4/4 time)
• Phrase - 8 bars (32 beats)
• BPM - Beats per minute

All timing in Spectralite is beat-relative, so changing BPM scales everything proportionally.

Step 1: Set Your BPM

1. In the toolbar, click the BPM value
2. Enter your track's BPM, or
3. Click Tap and tap along with the music (at least 4 taps)

The BPM display shows the current tempo.

Step 2: Use the Beat Matcher

For automatic detection:

1. Open the Beat Matcher panel via Window > Add panel > Beat Matcher
2. Play your music through your system
3. Spectralite analyzes the audio and suggests BPM
4. Click Apply to use the detected tempo

Manual Sync

If automatic detection isn't accurate:

1. Use Tap Tempo while listening
2. Fine-tune with the BPM +/- buttons
3. Use Nudge to align the downbeat

Step 3: Create a Beat-Pulse Effect

A simple effect that flashes on each beat:

1. Create a new layer

2. In the Node Editor, add these nodes:

   • Input > Time - Use the Beat Progress output (cycles 0-1 each beat)
   • Arithmetic > Subtract - Subtract from 1 to invert (1 at beat start, 0 at end)
   • Output > Output - With white color

3. Connect: Time (Beat Progress) → Subtract (from 1.0) → Output

The result: A flash that decays each beat.

Step 4: Create a Bar-Based Effect

Effects that cycle every 4 beats:

1. Use the Input > Time node's Bar Progress output (cycles 0-1 every 4 beats)
2. Use this as your animation driver
3. Connect to color or position nodes

Example: Color that shifts each bar

• Time (Bar Progress) → HSL to RGB (to Hue) → Combine Color → Output

Step 5: Create Phrase-Based Effects

For longer cycles (8 bars / 32 beats):

1. Use the Time node's Cumulative Beat Index output
2. Divide by 32 to get a 32-beat cycle
3. Use math: Time (Cumulative Beat Index) → Divide (by 32) → Fractional Part

Step 6: Add Beat-Reactive Shapes

Combine beat sync with visual patterns:

1. Create a chase effect with Pixel Position
2. Multiply the chase position by the Beat Progress value from Time
3. The chase advances on each beat

Time (Beat Progress) ──► Multiply ──► Add ──► Fractional Part ──► HSL to RGB ──► Combine Color ──► Output
                              │
Pixel Position ───────────────┘

Step 7: Use the Beat Grid

The Timeline's beat grid helps with timing:

1. Enable Snap to Beat in the Timeline
2. Drag clips to align with beat boundaries
3. Use Zoom to see individual beats or full phrases

Beat Patterns

Create on/off patterns:

1. In Layer Settings, find Beat Pattern
2. Click beats to toggle on/off
3. The layer only plays on active beats

Example patterns:

• Every beat: 1 1 1 1
• Every other: 1 0 1 0
• Syncopated: 1 0 0 1

Step 8: Tap Tempo During Performance

For live shows:

1. Assign Tap Tempo to a MIDI button
2. Tap along when the tempo changes
3. Spectralite smoothly adjusts

Advanced: Multiple Time Divisions

Create complex rhythms by combining:

• Beat-level pulses (quarter notes)
• Half-beat details (eighth notes)
• Bar-level sweeps
• Phrase-level color changes

Layer these for rich, musical lighting.

Troubleshooting

Effects feel off-beat?

• Check that BPM is exact
• Use the beat nudge to align the downbeat
• Verify your audio isn't delayed

Too intense?

• Use gentler curves (sine instead of linear)
• Reduce effect opacity
• Add fade in/out to beats

Next Steps

• Build a complete show
• Set up MIDI control
• Explore wave nodes