sonic surrounds

The article below is copied directly from the Spatial Audio Research blog of the Quality and Usability Lab at TU Berlin in order to help spread the word on this toolbox.  The toolbox comes from the AABBA Project (aural assessment by means of binaural algorithms) [pdf], which was introduced by Jens Blauert at the 2009 International Symposium on Auditory and Audiological Research (ISAAR).
I’ve been using their Auditory Modelling Toolbox for the Lindemann analysis below, and found it to be very well developed.

July 26, 2010 in MATLAB by Hagen Wierstorf | No comments

A new version of the growing Auditory Modelling Toolbox has been released. The main new feature is a binaural model after Lindemann (1986a) that uses a running cross-correlation with inhibition to predict the perceived lateralization of an auditory event. The output of the model depends on the auditory filters and on the time (see figure below).

To install it, you can download it from Sourceforge. You also have to install the Linear Time/frequency Toolbox. Then in Matlab or Octave just go to the directories of the toolboxes and run:

>> ltfatstart
>> amtstart

After this you are able to use the Lindemann model, see help lindemann for an introduction. To produce the figure below, you can run:

>> demo_lindemann;

Another very nice feature is the function exp_lindemann1986a that is able to reproduce the figures of the Lindemann paper. For example to reproduce figure 6 of the paper, just type exp_lindemann('fig6'). The model is under further development and will include in the next release a version of the method proposed byGaik (1993) to identify natural combinations of ITDs and ILDs. Further a version of theBreebaart model will also be included in one of the next releases.

From Peter Mcilwain, via the ACMA mailing list, comes the following news of the Nodal composing tool.

Nodal has been released for OSX and now Windows. Its free and has attracted some interest in the computer music community. For those unfamiliar with Nodal: Nodal is a generative software application for composing music. The software is produced at the Centre for Electronic Media Art (CEMA), Monash University, Australia. It uses a novel method for the notation and playing of MIDI based music. This method is based around the concept of a user-defined graph. The graph consists of nodes (musical events) and edges (connections between events). The composer interactively defines the graph, which is then traversed by any number of virtual players that play the musical events as they encounter them on the graph. The time taken by a player to travel from one node to another is based on the length of the edges that connect the nodes.

here’s a screenshot of the Pd interface that I developed to perform for Electrofringe 2006.

click on the image for full sized version:

I made heavy use of the (now quite usable) Graph on Parent feature - so that I could instantiate abstraction subpatches that created each of those GUI blocks in the patch.

Blocks aren’t really well labeled in this screenshot, but from left to right, top to bottom, these are the abstractions I developed and used in the patch:

• on the first row:
• a timer (clock), so i know how long i’ve been playing
• a “heartbeat” synth i made which emits a nice low bass pulse
• then three instances of the same ambisonic audio file player (that plays back my 4 channel ambisonic field recordings, and decodes them to 5 channel surround format)
• a single instance of a stereo audio file player
• on the second row:
• two instances of my 5 channel granulator - based on an improved version of the stereo granulator i’ve released elsewhere on my website
• a surround glitch/pop generator based on filtered single sample impulses with controlled stochastic triggering and panning
• and on the final row:
• a CPU load meter
• DSP switch
• mixer for all the abstractions, grouped into foreground and background sounds
• and the 5 channel output and recorder - which was the last thing i implemented, and seemed unreliable, so i didn’t use it to record my performance live. i’ll record a version sometime soon.

The Institute for Computermusic and Sound Technology ICST releases version 1.1 of the ICST Ambisonics Externals for Max/MSP, under the LGPL.

The objects are:

• ambiencode~ - encode n audio-channels in up to 3rd order ambisonic b-format
• ambidecode~ - decode up to 3rd order ambisonic b-format to n audio-channels
• ambimonitor - graphical user interface object for sound-source placement
• ambicontrol - control sound-sources in the ambimonitor in a variety of ways

They can be downloaded here, with sourcecode in the packages.

I edited Thomas Ouellet Fredericks’ Max/MSP patch for Arduino (available here) which uses his SimpleMessageSystem to control outputs and read digital and analog inputs.

The original patch only read the analog and digital inputs to the Max console. My modification streams the analog and digital inputs into number boxes that can then be used to control other Max patches. Here’s an image of the patch:

Get the modified patch here.

my addition