How to make a music visualizer in Scratch

このコンテンツはまだ日本語訳がありません。

💡 Need help creating stunning audio visualizations? Want to learn advanced multimedia techniques? 🚀 Get Expert Help

AudioVisual_Dev

Posted on March 31, 2025 • Advanced

🎵 Creating a Music Visualizer Without Microphone

Hey everyone! I’m trying to build a music visualizer similar to what you see in Monstercat videos, but I don’t want to use microphone input. I want to create visualizations that sync with pre-recorded audio files (MP4/MP3). 🎶

Most tutorials I’ve found require live microphone input, but I need something that works with existing audio tracks. Any ideas on how to approach this?

👍 Like (18)💬 Reply 🔗 Share

SoundMaster_Pro

Replied 3 hours later • ⭐ Best Answer

Great question @AudioVisual_Dev! Creating music visualizers in Scratch without microphone input is definitely possible. Here’s a comprehensive approach:

🎯 Music Visualizer Creation Flow

Here’s how to build an effective music visualizer system:

flowchart TD A[🎵 Audio File] --> B[Extract Audio Data] B --> C[Convert to Frequency Data] C --> D[Create Data Lists in Scratch] D --> E[🎮 Scratch Visualizer] E --> F[Read Audio Data Lists] F --> G[Generate Visual Elements] G --> H{Visualization Type?} H -->|Bars| I[📊 Bar Visualizer] H -->|Circles| J[⭕ Circular Visualizer] H -->|Waves| K[🌊 Waveform Visualizer] I --> L[Update Bar Heights] J --> M[Update Circle Sizes] K --> N[Update Wave Patterns] L --> O[🎨 Apply Visual Effects] M --> O N --> O O --> P[Sync with Audio Playback] P --> Q{Continue?} Q -->|Yes| F Q -->|No| R[🏁 End Visualization] style A fill:#e1f5fe style E fill:#f3e5f5 style O fill:#e8f5e8 style R fill:#fce4ec

🔧 Method 1: Pre-processed Audio Data

The most effective approach is to extract audio data beforehand:

Step 1: Extract Audio Data (Outside Scratch)

Use Audacity or similar software to analyze your audio file
Export frequency spectrum data as text/CSV
Convert this data into Scratch-compatible lists

Step 2: Import Data to Scratch

    when flag clicked
// Create lists for different frequency bands
set [bass data v] to [10 15 20 25 18 12 8 15 22 30 25 20]
set [mid data v] to [5 8 12 15 18 20 16 12 10 8 6 9]
set [treble data v] to [2 4 6 8 10 12 8 6 4 3 2 5]
set [time index v] to [1]

📊 Method 2: Bar Visualizer Implementation

Create animated bars that respond to audio data:

    // For each bar sprite
when flag clicked
forever
// Get current audio data point
set [current value v] to (item (time index) of [bass data v])

// Scale the bar height
set size to ((current value) * [5])%

// Add color effects based on intensity
if <(current value) > [20]> then
set [color v] effect to [0] // Red for high intensity
else
if <(current value) > [10]> then
set [color v] effect to [60] // Yellow for medium
else
set [color v] effect to [120] // Blue for low
end
end

wait [0.1] seconds
end

⭕ Method 3: Circular Visualizer

Create a radial visualization pattern:

    // For circular visualizer sprite
when flag clicked
forever
clear
set pen size to [3]

// Draw circle based on audio data
repeat [360]
set pen color to (((item (time index) of [bass data v]) * [10]) + [50])

// Calculate radius based on audio intensity
set [radius v] to ((item (time index) of [bass data v]) + [50])

// Draw point on circle
go to x: ((radius) * ([cos v] of (counter))) y: ((radius) * ([sin v] of (counter)))
pen down
pen up

change [counter v] by [1]
end

wait [0.05] seconds
end

🌊 Method 4: Waveform Visualizer

Create flowing wave patterns:

    // Waveform visualization
when flag clicked
forever
clear
set pen size to [2]
pen down

set x to [-240]
repeat [480]
// Get wave height from audio data
set [wave height v] to (item ((x + [240]) / [20]) of [mid data v])

// Draw wave point
go to x: (x) y: ((wave height) * [5])

change x by [1]
end

pen up
wait [0.08] seconds
end

🎨 Advanced Visual Effects

Add stunning visual enhancements:

    // Particle effects for intense moments
when flag clicked
forever
if <(item (time index) of [bass data v]) > [25]> then
// Create particle burst
repeat [10]
create clone of [particle v]
end

// Screen flash effect
set [brightness v] effect to [50]
wait [0.1] seconds
set [brightness v] effect to [0]
end

wait [0.1] seconds
end

// Particle clone behavior
when I start as a clone
set size to [20]%
point in direction (pick random [-180] to [180])
repeat [30]
move [5] steps
change size by [-1]
change [ghost v] effect by [3]
end
delete this clone

⏱️ Synchronization Tips

Timing Control: Use a master timer to keep visuals in sync with audio
Data Smoothing: Average multiple data points for smoother animations
Performance: Limit the number of visual elements to maintain smooth playback
Testing: Test with different audio types to ensure versatility

This approach gives you full control over the visualization without needing real-time audio input! 🎉

👍 Like (67)💬 Reply 🏆 Mark as Best Answer

AudioVisual_Dev

Replied 45 minutes later

@SoundMaster_Pro This is absolutely incredible! 🤩 Thank you so much for the detailed explanation!

I’m particularly interested in the circular visualizer approach. Quick question - what’s the best way to extract the frequency data from Audacity? Should I use the Plot Spectrum feature?

👍 Like (12)💬 Reply

AudioTech_Expert

Replied 1 hour later

@AudioVisual_Dev Great question! For Audacity data extraction: