VSpace Introduction

VSpace makes recordings of sounds played back in a virtual acoustic space. It is designed for use by computer musicians who aren't afraid to use a script language. The acoustic space is miked up with any number of virtual microphones of various types. In many ways Space is a `mixer' program, taking a script describing the space, microphones and the sounds moving within it.

VSpace is a self-contained program forming part of MNLib, a set of C++ libraries and programs for audio processing and music. MNLib is designed with portable C++ code for use on Linux, Microsoft platforms and others. VSpace uses Bison and Flex in addition to C++ which can cause compilation difficulties. VSpace, MNLib and their documentation are Copyright 1999-2000 Richard W.E. Furse (all rights reserved).

VSpace may be downloaded from http://www.muse.demon.co.uk/mn_download.html.

VSpace is an efficient piece of software given the complexity of the models in use. There are further improvements that can be made but currently I have no reason to as the software is already more than fast enough for my purposes.

To construct the recording a number of auditory `cues' are synthesised to provide a more `real' effect that can be produced using conventional techniques. Cues synthesised include:

• Cardioid, Cardioid pairs, Figure-of-eight, Omnidirectional and Ambisonic microphones (first and second order).
• Early Reflections off walls (to a depth chosen by the user).
• Sound sources that may move in linear and circular motion. Sound sources may be directional.
• Inter-aural difference (when microphones are placed close to one another).
• Doppler shift induced using accurate model (moving write head delay lines and careful volume shading).
• Inverse square law plus special behaviour for use within the core sphere in synthesised Ambisonic sound fields producing a better image than is possible with real Ambisonic microphones.
• Distance filtering.
• Reverb.

There is no dummy head implementation in this version of MN. This is because I don't have a suitable set of HRTFs to work from. I played with the MIT Kemar set of impulse responses with the MLib3 audio processing library but though reasonably effective, they colour the audio too much to be musically useful (IMHO). If you have something better, please let me know and if I like them I'll reimplement the dummy head recorder in MNLib and VSpace.

Links

• Ambisonic Player Documentation
• General 3D Audio Information
• MN Library Downloads
• MN Library Main Index
• VSpace Script Language
• VSpace Model
• VSpace Example Script

The author Richard Furse can be emailed as richard@muse.demon.co.uk.

"Ambisonics" is a registered trademark of Nimbus Communications International.