Master Panel Guide¶

Learn to control global tempo and create shared parameters across all cards.

What is the Master Panel?¶

The master panel sits above the four cards and provides controls that affect everything at once:

TEMPO: Controls the speed of all patterns
Global Sliders: Variables that any card can reference
Stop All: Stops all cards simultaneously

Think of the master panel as the conductor - it sets the tempo and overall tone, while each card (musician) plays their own part.

TEMPO Control¶

What TEMPO Does¶

TEMPO controls how fast patterns play across all cards. When you adjust TEMPO, every playing pattern speeds up or slows down together.

Default Setup¶

The master panel includes a TEMPO slider:

let TEMPO = slider(30, 15, 45);

Parameter	Value	Meaning
Default	30	Starting speed
Min	15	Slowest setting
Max	45	Fastest setting

How Speed Works¶

r0astr uses CPS (Cycles Per Second) internally. You don't need to understand the math - just know that:

Higher TEMPO = faster patterns
Lower TEMPO = slower patterns
All cards follow the same tempo

Practical Use¶

Start with the default tempo
Use the slider to find a comfortable speed
All patterns automatically adjust

Performance Tip

Subtle tempo changes during a performance can add dynamics. Try slowly increasing tempo to build energy.

Global Effect Sliders¶

Create sliders in the master panel that control parameters across all cards.

Why Use Global Sliders?¶

Instead of adding separate filter sliders to each card, create one in the master panel:

Single control affects everything
Consistent effect across all instruments
Great for sweeps and buildups

Creating a Global Slider¶

In the master panel code:

let SLIDER_LPF = slider(800, 100, 5000);

This creates: - A slider named SLIDER_LPF - Starting at 800 Hz - Range from 100 Hz to 5000 Hz

Using in Cards¶

Reference the variable name in any card:

// Card 1
s("bd*4").lpf(SLIDER_LPF)

// Card 2
note("c2 ~ c2 e2").s("sawtooth").lpf(SLIDER_LPF)

// Card 3
n("0 2 4").scale("C4:minor").s("triangle").lpf(SLIDER_LPF)

Now one slider controls the filter on all three cards.

Multiple Global Sliders¶

Add as many as you need:

// Master Panel
let SLIDER_LPF = slider(800, 100, 5000);
let REVERB = slider(0.3, 0, 1);
let MASTER_GAIN = slider(0.8, 0, 1);

Use them in cards:

note("c2").lpf(SLIDER_LPF).room(REVERB).gain(MASTER_GAIN)

Variable Reference Workflow¶

Step 1: Define in Master Panel¶

Write your slider definitions in the master panel:

let FILTER = slider(1000, 200, 4000);
let SPACE = slider(0.5, 0, 1);

Step 2: Use in Card Patterns¶

Reference the variable names (exactly as written) in any card:

// This card uses both global sliders
note("c2 e2 g2")
  .s("sawtooth")
  .lpf(FILTER)
  .room(SPACE)
  .gain(0.6)

Step 3: Control in Real-Time¶

Adjust the sliders while patterns play. All cards using those variables update instantly.

Naming Conventions¶

Use clear, descriptive names:

Good	Why
`SLIDER_LPF`	Clear it's a slider, controls low-pass
`MASTER_GAIN`	Indicates global volume
`REVERB`	Simple and obvious
`TEMPO`	Special - controls global speed

Creating Custom Sliders¶

Basic Syntax¶

let NAME = slider(default, min, max);

Part	Description
`let NAME`	Variable name to use in cards
`slider()`	Creates a slider control
`default`	Starting value
`min`	Minimum value
`max`	Maximum value

Examples¶

Filter Control (Hz):

let FILTER_CUTOFF = slider(800, 100, 8000);

Volume Control (0-1):

let VOLUME = slider(0.7, 0, 1);

Reverb Amount (0-1):

let ROOM_SIZE = slider(0.4, 0, 1);

Speed Modifier:

let SPEED = slider(1, 0.5, 4);

Complete Example¶

Master Panel:

let TEMPO = slider(30, 15, 45);
let LPF = slider(1200, 100, 4000);
let REVERB = slider(0.3, 0, 0.9);
let MASTER = slider(0.8, 0, 1);

Card using globals:

note("c2 e2 g2 e2")
  .s("sawtooth")
  .lpf(LPF)
  .room(REVERB)
  .gain(MASTER)

Stop All¶

What It Does¶

The Stop All button immediately stops every playing pattern across all cards.

When to Use¶

End of performance: Clean stop
Reset: Start fresh
Emergency: Something sounds wrong

Behavior¶

When you click Stop All:

All cards stop immediately
Cards remain paused (not reset)
Code in each card is preserved
Click Play on individual cards to restart

Advanced: How Master Panel Works¶

For Advanced Users

This section explains the technical implementation. You don't need to understand this to use r0astr effectively.

Parsing Differences¶

The master panel works differently from cards:

Feature	Cards	Master Panel
Code evaluation	Strudel transpiler	Regex parsing
Pattern execution	Yes	No
Slider detection	Automatic	Manual parsing

Why Regex?¶

The Strudel transpiler can block when used in the master panel context. To avoid this, r0astr parses master panel code with regex to extract slider definitions.

TEMPO Special Handling¶

TEMPO isn't just a variable - it controls the scheduler:

Master panel code defines: let TEMPO = slider(...);
r0astr detects the TEMPO variable
Changes are converted to CPS (cycles per second)
The scheduler's speed is updated: scheduler.setCps(value)

Slider Detection Pattern¶

Master panel sliders must follow this exact format:

let VARIABLE_NAME = slider(default, min, max);

The parser looks for: - let keyword - Variable name (letters, numbers, underscores) - = slider( - Three numeric values

For detailed technical information, see the Architecture documentation.

Quick Reference¶

Master Panel Syntax¶

// Required for tempo control
let TEMPO = slider(30, 15, 45);

// Optional global sliders
let SLIDER_LPF = slider(800, 100, 5000);
let REVERB = slider(0.3, 0, 1);
let GAIN = slider(0.7, 0, 1);

Card Usage¶

// Reference global sliders by name
note("c2").lpf(SLIDER_LPF).room(REVERB).gain(GAIN)

Next Steps¶

Pattern Library

Ready-to-use patterns that work with global sliders.

Pattern Library
Architecture

Deep technical details for developers.

Architecture