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Automation Parameters

Plugdata allows you to expose patch parameters to your DAW for automation using the [param] object. This guide covers everything you need to know about creating, managing, and using automation parameters.
Automation parameters are primarily used when running plugdata as a plugin in a DAW. In standalone mode, parameters can still be created and controlled via MIDI or OSC.

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Understanding Parameters

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What are Parameters?

Parameters are values in your patch that can be:
  • Automated in your DAW timeline
  • Controlled by MIDI CC or other controllers
  • Saved with your DAW project
  • Displayed in your DAW’s plugin interface
  • Modulated by DAW envelopes and LFOs

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The [param] Object

The [param] object bridges your Pd patch and DAW automation: 
[param filter_cutoff]
  |
[lop~ 1000]        # Control filter cutoff from DAW

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Creating Parameters

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Using the Automation Panel

The easiest way to create parameters:
1

Open Automation Panel

Click the Parameters tab in the sidebar (or press Cmd/Ctrl+B and select it)
2

Click + Button

Click the + button at the bottom of the panel to create a new parameter
3

Configure Parameter

Set the parameter properties:
  • Name - Descriptive name (e.g., “Filter Cutoff”)
  • Range - Minimum and maximum values
  • Mode - Float, Integer, Logarithmic, or Exponential
4

Add to Patch

Drag the parameter from the panel onto your canvas to create a [param] object

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Creating [param] Objects Directly

You can also create parameters directly in your patch: 
# Basic parameter
[param volume]

# Parameter with auto-handling
[param volume 1]

# The parameter will appear in the Automation Panel
Arguments:
  1. Symbol - Parameter name (required)
  2. Float - Enable auto-handling (0 or 1, default: 0)
Use descriptive, unique names for parameters. Spaces are allowed: [param Filter Cutoff]

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Parameter Configuration

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Setting Parameter Range

Configure the minimum and maximum values:
  1. Click the expand arrow (▸) on the parameter
  2. Adjust Range with the min/max fields
  3. Values update immediately in the DAW
Common Ranges:
  • Volume: 0 to 1 (or 0 to 127 for MIDI-style)
  • Frequency: 20 to 20000 Hz
  • Percentage: 0 to 100
  • Pan: -1 to 1 or 0 to 127

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Parameter Modes

Choose the scaling mode that fits your parameter:
Linear floating-point values
  • Default mode
  • Continuous values with decimals
  • Even spacing across range
Best for:
  • Volume controls
  • Pan positions
  • Mix amounts
[mode 1(
  |
[param mix]
Whole number values only
  • Steps in integer increments
  • No decimal values
Best for:
  • Selection indices
  • Step sequencer steps
  • Waveform selection
[mode 2(
  |
[param waveform]  # 0=sine, 1=saw, 2=square
Logarithmic scaling
  • More resolution at low values
  • Less resolution at high values
  • Matches human perception
Best for:
  • Frequency controls
  • Filter cutoffs
  • Decay times
[mode 3(
  |
[param filter_freq]  # Range: 20-20000 Hz
Exponential scaling
  • More resolution at high values
  • Less resolution at low values
Best for:
  • Envelope times (when you need precision at longer times)
  • Some specialized controls
[mode 4(
  |
[param release_time]

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Auto-Handling Mode

The second argument enables automatic DAW communication: 
[param volume 1]   # Auto-handling enabled
With auto-handling (1):
  • Automatically reports changes to DAW
  • Handles gesture begin/end for automation recording
  • Best for most use cases
Without auto-handling (0):
  • Manual control over change reporting
  • Use second inlet to control change state
  • For advanced automation scenarios

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Using Parameters in Patches

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Basic Parameter Control

# Simple volume control
[param master_volume]
  |
[/ 100]              # Scale 0-100 to 0-1
  |
[*~]                 # Apply to audio signal

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Mapping to GUI Objects

Connect parameters to number boxes and sliders: 
# Two-way parameter/GUI connection
[nbx]                # Number box
  |  |
  |  [param cutoff]  # Parameter follows number box
  |    |
  +----+             # And number box follows parameter

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Multiple Parameters

Create complex control structures: 
# Synthesizer voice parameters
[param pitch]        [param volume]      [param filter]
     |                    |                    |
  [mtof]              [/ 127]              [/ 127]
     |                    |                    |
  [osc~]                [*~]               [lop~]
     |                    |                    |
     +--------------------+--------------------+
                          |
                       [dac~]

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Advanced Parameter Techniques

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Parameter Smoothing

Avoid zipper noise with smoothing: 
[param filter_cutoff]
  |
[line~]              # Smooth parameter changes
  |
[lop~]               # Smoother filter response

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Parameter Scaling

Transform parameter ranges: 
# Map 0-1 parameter to 20-20000 Hz logarithmically
[param freq_control]  # Range: 0 to 1
  |
[expr pow(20000/20, $f1) * 20]  
  |
[lop~ $1]            # Frequency in Hz

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Conditional Parameters

Use parameters to switch behavior: 
[param filter_type]  # Range: 0 to 2 (integer mode)
  |
[select 0 1 2]
  |   |   |
  |   |   [send~ highpass]
  |   [send~ bandpass]  
  [send~ lowpass]

[receive~ lowpass]
  |
[lop~ 1000]
  |
[outlet~]

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Parameter Groups

Organize related parameters: 
# Oscillator group
[param osc_freq]     [param osc_shape]   [param osc_width]

# Filter group  
[param filt_cutoff]  [param filt_res]    [param filt_type]

# Envelope group
[param env_attack]   [param env_decay]   [param env_release]
Use consistent naming conventions like section_parameter (e.g., filter_cutoff, filter_resonance) to keep parameters organized.

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DAW Integration

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Accessing Parameters in Your DAW

Once parameters are created:
1

Load Plugin

Open plugdata as a plugin in your DAW
2

Find Parameters

Parameters appear in:
  • DAW’s automation lane list
  • Plugin parameter list
  • Generic plugin UI (if supported)
3

Automate

Record or draw automation as with any plugin parameter
4

Control

Map to MIDI controllers, DAW faders, or modulation sources

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Parameter Persistence

Parameters are saved with:
  • DAW Project - Current parameter values
  • Automation Data - All automation lanes
  • Plugin State - When recalling presets

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MIDI Mapping

Connect MIDI CC to parameters: 
[ctlin 1]            # MIDI CC 1 (mod wheel)
  |
[/ 127]              # Normalize to 0-1
  |
[param mod_amount]   # Control parameter via MIDI

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Parameter Best Practices

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Naming Conventions

✅ Good names:
  • filter_cutoff
  • osc_1_pitch
  • reverb_mix
  • envelope_attack
❌ Avoid:
  • param1, param2 (not descriptive)
  • x, y, z (too generic)
  • Very long names (truncated in some DAWs)

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Range Selection

Consider:
  • Musical range (e.g., 20-20000 Hz for frequency)
  • User expectations (0-100 for percentage)
  • Control precision needed
  • Scaling mode (linear vs logarithmic)

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Organization

For large patches:
  1. Group related parameters by function
  2. Use consistent prefixes (osc_, filt_, env_)
  3. Order parameters logically in the automation panel
  4. Document parameter purposes in comments
[comment Oscillator Parameters]
[param osc_frequency]  # 20-20000 Hz, logarithmic
[param osc_detune]     # -100 to 100 cents, linear
[param osc_wave]       # 0-3, integer (sine/saw/square/tri)

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Troubleshooting

Solutions:
  • Ensure parameter is created before loading in DAW
  • Try reloading the plugin
  • Check parameter name doesn’t have special characters
  • Verify the parameter exists in the Automation Panel
Check:
  • Parameter is connected to something in the patch
  • Patch is in run mode (not edit mode)
  • DSP is enabled
  • Automation is actually written in the DAW
Solutions:
  • Add smoothing with [line~] for audio-rate control
  • Check parameter mode (use float for smooth values)
  • Increase update rate if using [snapshot~]
Fixes:
  • Verify range is set correctly in Automation Panel
  • Check for scaling math errors in patch
  • Use correct mode (logarithmic for frequency, etc.)

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Example: Complete Synth Voice

Here’s a complete example using parameters: 
# Oscillator section
[param pitch]           # MIDI note number
[param detune]          # -100 to 100 cents
  |       |
  |     [/ 100]          
  |       |
[mtof]  [+ 1]           # Convert to Hz and detune
  |       |
  +-------+
      |
   [osc~]
      |
# Filter section  
   [*~]                 # VCA
      |
  [lop~]                # Filter
      |
   [*~]                 # Master volume
      |
   [dac~]

# Parameter connections
[param filter_cutoff]   # 20-20000 Hz, logarithmic
  |
[lop~ $1]

[param amp_level]       # 0-1, linear
  |
[*~ $1]

[param master_volume]   # 0-1, linear  
  |
[*~ $1]

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