Real-time-SDN

Scattering Delay Networks reverb plugin considering walls absorption.

Exposed parameters

The plugin exposes the following parameters:

• Source level (dB)
• Source position (3 x 0-1 normalized values)
• Listener position (3 x 0-1 normalized values)
• Listener rotation (3 x 0-360 degrees)
• Output mode (mono, stereo, ACN Ambisonics 1st-5th order)
• Room dimensions (3 x 1-100 meters)
• Wall absorption coefficients (8 x 0-1 absorption coefficients per wall)
• Line-of-sight component (on/off)

Main classes

• Room: The main class representing the simulation
• Node: Parent class for all the moving objects in the simulation
• Source: Implements the sound origin
• Receiver: Models the listener and communicates with the Microphone class
• Microphone: virtual class used as a parent for all the classes implementing the supported output types
• ScatteringNode: Characterizes the first-order reflection’s point of contact with the room walls. Also manages the filtering of the signal
• WaveGuide: Controls the sound propagation in the system. It should be noted that the single instance of this class is mono-directional

Other tech-specs

Some other info about the plugin:

• Y-up left-handed coordinates system
• Shoebox geometry
• Only one omnidirectional source and one listener
• Multi-channel inputs are treated as mono (input channels are summed up)

Dependencies

• JUCE
• Eigen
• BRT Library (optional)

Build notes

The plugin version with HRTF processing requires the BRT Library to be included. Additionaly, on Mac or Linux systems, the "mysofa.lib" and "zlibstatic.lib" files (provided by the BRT Library) must also be added as external libraries to link.

References

This work is based on the following publications:

Fontana, M. (2023). Scattering delay networks for real time audio in augmented reality. Master thesis. Università degli Studi di Milano. Milan.

De Sena, E., Hacihabiboglu, H., & Cvetkovic, Z. (2011, February). Scattering delay network: An interactive reverberator for computer games. In Audio Engineering Society Conference: 41st International Conference: Audio for Games. Audio Engineering Society.

De Sena, E., Hacιhabiboğlu, H., Cvetković, Z., & Smith, J. O. (2015). Efficient synthesis of room acoustics via scattering delay networks. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 23(9), 1478-1492.