bob~ (Max external)

Moog ladder resonant filter simulation for Max/MSP.

Port of the bob~ object from Pure Data, originally written by Miller Puckette. Platforms : macOS (intel, silicon) + win

The filter is implemented using Runge-Kutta numerical integration of a nonlinear differential equation modelling the Moog transistor ladder.

(thanks to Mathieu Staub for pointing me to bob~ during this class discussion)

References:

• Tim Stilson — Analyzing the Moog VCF with Considerations for Digital Implementation
• Timothy E. Stinchcombe — Analysis of the Moog Transistor Ladder
• Antti Huovilainen — Non-linear digital implementation of the Moog ladder filter

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Installation

1. Download the latest release: bob-for-max-v1.0.0.zip
2. Unzip the archive.
3. Place the bob~ folder into your Max Packages directory:
   • macOS: ~/Documents/Max 9/Packages/
   • Windows: Documents\Max 9\Packages\
4. Restart Max.

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Inlets

1. signal — audio input
2. signal / float — cutoff frequency (Hz)
3. signal / float — resonance

Outlet

1. signal — filtered output

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Attributes

@oversample
Oversampling factor for the Runge-Kutta solver.

@saturation
Controls the transistor saturation function.

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Messages

clear
Reset filter state.

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License

This software is based on the bob~ object from Pure Data by Miller Puckette and others.

Released under the Standard Improved BSD License.
See LICENSE.txt.

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Author

Max port by Julien Bayle / Structure Void

https://structure-void.com