mklAVE concept
An Auditory Virtual Environment for the MedienKunstLabor
Sound and music is recognized as a spatial and sculptural phenomenon ever since the Renaissance, although only the currently available technologies of new media allow (beside the arbitrary 3-dimensional distribution of sound) the creation of whole sound-environments. An Auditory Virtual Environment (AVE) is a virtual environment (VE) that focuses on the auditory domain only. It sees itself independent from other modalities like vision and tactility. The mklAVE project aims at a reference-implementation of an AVE for media-art rooms.
The assumption that every sound environment is defined through its boundary conditions, which can be understood as an enfolding vibrating membrane as the basic model of this AVE implementation. The enclosed room of the membrane is stimulating the desired sound field. Altering the conditions of this virtual membrane, means to change the whole physics of the room, which is feasible in real-time.
So the interest is no longer in moving sounds through a room, but to create virtual surrounding sound environments which can be modified dynamically. Room is experienced and defined through the behavior of the sound depending on the rooms conditions. In other words you can imagine room and sound as the same one thing: an environment in which room is defined through sound and vice versa. Such an environment can be thought as a „breathing“ sculpture which is palpated by moving through it.
Virtual Rooms
Room-simulation algorithms create virtual rooms which are superposed to the real room. Using a bunch of microphones room reflections of the analogue sound sources are rebuilt in order to simulate virtual acoustic rooms. The latter could be the simulation of real and the invention of artificial rooms. This „room in room reverberation“ is used for dynamically changing the acoustic properties of the room.
Ambisonics
Higher Order Ambisonics (HOA) is used to implement the discussed features of the AVE. It is a series of techniques to record and replay a sound field. By means of encoding and decoding sound information on a number of channels, a 2- or 3- dimensional sound field can be presented. Ambisonics was mainly developed by Michael Gerzon and Peter Fellgett in the early 1970s.
In contrast to more common playback systems such as Stereo or Dolby Surround Ambisonics tries to resynthesize the represented sound field mathematically correct. Therefore sounds arriving from all directions are treated equally. All speakers are generally used to localise a sound in any directions. As a result the number of speakers is flexible. This portability of the format makes it easy to adapt an ambisonics-encoded signal to different loudspeaker settings. Thus a three-dimensional sound field is already presented with four loudspeaker channels. Conventional formats are even with 6 channels only be able to present a two dimensional sound field. The sound-system installed in MKL allows to operate HOA from first up to sixth order.
