SpaceMaps & Manifold Interface Amplitude Panning

The SpaceMap spatialization system was originally developed by Meyer Sound Laboratories Inc. for their commercial digital show control system Matrix3 and D-Mitri but has now been ported to Max MSP and Pure Data by Zachery Seldess as a really nice suite of externals entitled Manifold-Interface Amplitude Panning (MIAP). Zachary presented this work at the 137th Convention of the AES and in the following two vidoes he discusses the origins of this technique and demonstrates the MIAP objects.

History and Significance of the SpaceMap concept - by Zachery Seldess

 

 

Demonstrations of the MIAP objects - by Zachery Seldess

 

 

SpaceMaps can be used to create familiar multi-channel panners in which the layout of the interface directly mirrors the physical layout of the loudspeakers (as shown in the 5.1 and Auro-3D examples below), and as trajectories are stored independently, they can easily be adapted to different types of arrays.

 

Importantly however, SpaceMaps do need to be arranged in this way and entirely abstract arrangements are also possible. Traditional graphical interfaces that mirror the physical layout of the loudspeaker array are easy to understand but can be quite deceptive. For example, when a sound is stereophonically panned to the centre of a 5.1 loudspeaker array the interface visually suggests that the sound will be localized by the listener(s) inside the array, however this is not really the case. In reality, the source is simply reproduced equally by each loudspeaker and so localization will be strongly influenced by several factors, such as listener location. This misconception and the common erroneous equating of graphical layouts with the actual behaviour of spatial audio is a direct consequence of this type of interface design. In effect, interfaces such as these explicitly suggest real space (through the direct replication of the physical loudspeaker layout), while the real and more complex behaviour of spatial audio is only implied. The abstract manifold of a SpaceMap is in contrast an explicitly abstract interface, and so can perhaps avoid some of the pitfalls of overtly graphical notions of spatial sound and of course, spatial music.

SpaceMaps can also be used as a flexible, transferrable configuration and performance tool for live diffusion, in which faders (or other control surfaces) can be mapped to arbitrary arrangements of loudspeakers, much like the concept of the multi-point cross fader previously developed by James Mooney and David Moore for the M2 diffusion system. The SpaceMap could therefore represent a new type of interface for the composition and performance of spatial electroacoustic music which is equally applicable to both multichannel and stereo diffusion work, and which could greatly simplify the process of transferring works between different loudspeaker configurations.

These ideas are discussed in more detail in the following paper presented at BEAST FEaST 2015 at the University of Birmingham, 30 April – 2 May, 2015.

SpaceMaps, Manifolds and a New Interface Paradigm for Spatial Music Performance

The paper outlines some example diffusion strategies, the concept of the multi-point fader, and the transfer of pre-programmed trajectories between different loudspeaker configurations.

 

Stereo Diffusion example patches, SpaceMaps & TouchOSC Intefaces: MIAP-StereoDiffusion.zip

These patches illustrate the manual diffusion of a stereo source to a loudspeaker orchestra using MIAP. Common diffusion strategies such as unmasking, front-back movement and random distribution are implemented as SpaceMaps using Jonty Harrison's Main 8 loudspeaker orchestra configuration. This consists of 4 stereo pairs at front-distant, front-narrow, front-wide and rear positions.The patches include support for MIDI and OSX control via TouchOSC (a TouchOSC interface for the patch is also provided). A basic binaural rendering is also included using the multiconvolve~ object developed by Alex Harker and Pierre Alexandre Tremblay.

Requirements
MIAP (OSX only)by Zachary Seldess

multiconvolve~ (OSX only) by Alex Harker and Pierre Alexandre Tremblay

 

Apart from spatialization, SpaceMaps can also be used as an interactive, graphical interface for audio synthesis, interactive installations, and live performances. In the second half of this electroacoustic piece, the twelve notes of a tabletop guitar (fitted with a third bridge) are 'played' using a SpaceMap and a virtual model of a pendulum.


Spacemaps are also a very effective means of mapping gestural controllers and sensors, such as the GameTrak tether controller. This now discontinued golf game controller has long been used by laptop orchestras as a means of interacting with many different types of electronic instruments. While there are lots of different ways of mapping this controller (including some quite sophisticated tools based on machine learning), SpaceMaps can also be useful here. The following video demonstrates a prototype of String Pull, an interactive installation/instrument based around a GameTrak and two SpaceMaps, which in this case implement the mapping and also serve as a graphical display. GameTraks are usually placed on the floor, however placing it on its side allows for the full extension of the tethers and greatly expands the range of movement possible.