EAA Winter School — Cutting Edge in Spatial Audio

Franz Zotter has organized the course “Cutting Edge in Spatial Audio” at the EAA Winter School which was taking place before the 40th Italian (AIA) Annual Conference on Acoustics and the 39th German Annual Conference on Acoustics (DAGA) in Meran, Italy. The course featured talks on various topics in the field and live demonstration on a 24-channel loudspeaker system.

I have given a talk on the theoretical basis of Sound Field Synthesis techniques like higher-order Ambisonics (HOA) and Wave Field Sythesis (WFS). The slides of my talk are available on Speakerdeck. We furthermore gave a NFC-HOA and WFS demonstration using the SoundScape Renderer (SSR).

PANO_20130317_142141

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How does a stereo sound that moves with supersonic speed?

The question how a stereo would sound that passes the listener at superonic speed was discussed in a recent post of XKCD. I was quite suprised that the publication Reproduction of Virtual Sound Sources Moving at Supersonic Speeds in Wave Field Synthesis of Jens Ahrens and me helped in finding the answer to this interesting question. The overall perception when listing to music containing demonic messages was nicely summarized by the owner of XKCD

stereo_message

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Supplementary material for the paper “Perception of Focused Sources in Wave Field Synthesis”

Perception of Focused Sources in Wave Field Synthesis

This post contains additional material for the paper

Hagen Wierstorf, Alexander Raake, Matthias Geier, Sascha Spors. Perception of Focused Sources in Wave Field Synthesis. In J. Audio Soc. Eng. (2013)

We have released supplementary material on figshare.
There you will find data from the experiments plotted in the figures and a video showing the geometry of the setup together with listening examples.

All stimuli from the experiment can be listened to at the supplementary material for a paper at the 129th AES Convention.

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Paper: Perception of Focused Sources in Wave Field Synthesis

We have recently published an article about the perception of focused sources in Wave Field Synthesis in the Journal of the Audio Engineering Society.
It is open access and can be freely downloaded and distributed.

Perception of Focused Sources in Wave Field Synthesis

Hagen Wierstorf, Alexander Raake, Matthias Geier, Sascha Spors. Perception of Focused Sources in Wave Field Synthesis. In J. Audio Eng. Soc. (2013)

Supplementary material can be found on figshare.
There you will find data from the experiments plotted in the figures and a video showing the geometry of the setup together with listening examples.

All stimuli from the experiment can be listened to at the supplementary material for a contribution to the 129th AES Convention.

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Spatial audio impulse response compilation

Benjamin Bernschütz from the Laboratory for Acoustics, Audio Technology and Audio Signal Processing of the Cologne University of Applied Sciences has released a set of acoustic measurements under the Creative Commons license. The released data includes spatial impulses captured at the WDR broadcast studios, full sphere head-related impulse responses (HRIRs) for the Neumann KU 100 and anechoic recordings. The documentation and the datasets can be downloaded here.

Both the binaural room impulse responses (BRIRs) from the broadcast studios and the HRIRs can be used conveniently in the SoundScape Renderer (SSR) using binaural (room) synthesis. The MATLAB class shipped together with the data provides an export function for the SSR.

spatialAudioIRC_mid

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Special Session on Virtual Acoustics at AIA-DAGA 2013

The technical program of the AIA-DAGA 2013 — Conference on Acoustics is available for download (PDF). Franz Zotter, Filippo Fazi, Angelo Farina and myself have organized a special session on virtual acoustics. We have received more than 30 contributions which will be presented in a poster and lecture session lasting throughout the entire conference. Everybody interested in the topic is warmly welcome!

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Paper: Spatial Audio with the SoundScape Renderer

At the 27th Tonmeistertagung – VDT International Convention, Matthias Geier has reported on the ongoing redesign of the SoundScape Renderer (SSR). The next generation of the SSR is based on a redesigned signal processing core that allows for multi-threaded processing. Read more in the paper.

M. Geier and S. Spors. Spatial audio with the SoundScape Renderer. In 27th Tonmeis- tertagung – VDT International Convention, Cologne, Germany, November 2012.

Abstract — The SoundScape Renderer (SSR) is a versatile tool for realtime spatial audio reproduction, implementing a variety of headphone- and loudspeaker-based methods. Among others this includes Wave Field Synthesis, Higher Order Ambisonics and dynamic binaural synthesis. The SSR is free software licensed under the GNU General Public License. It uses the JACK audio framework and is currently available for Linux and Mac OS X. Interaction with the program is possible using the built-in graphical user interface and via a network interface. For headphone reproduction native support for a number of head trackers is included. Sound sources including their position and other information are represented in a so-called spatial audio scene. Scenes can be loaded from and saved to XML files. The scene description is independent from the rendering method. For instance, a spatial audio scene can be authored in a studio with headphones, using the binaural renderer. Later on, the scene can be performed in a di erent venue using loudspeakers, using Wave Field Synthesis. Recently, the signal processing core was rewritten for multi-threaded processing and independence of the audio backend. Since then, all rendering modules of the SSR are also available as a software library which can be used to create stand-alone programs as well as plugins for existing audio software. Currently, all rendering modules are available as Externals for Puredata and as MEX-files for Octave/Matlab.

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AES Conference on Sound Field Control, Engineering And Perception

The call for papers for the 52nd International Conference of the Audio Engineering Society considers contributions from

  • Sound field control theory
  • Sound field sampling for control purposes
  • Signal processing for sound field control
  • Active and adaptive sound control
  • Transducers, array design, beam-forming
  • Sound field control applications
  • Spatial sound field control and multichannel audio
  • Psychoacoustics
  • Perceptual models
  • Sound quality evaluation

Deadline for paper proposals is 2013 January 31 15. February 2013.

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Sonification of EEG Signals

My former colleague Robert Schleicher and his team at Quality and Usability Lab (TU Berlin) has released a set of OpenSource tools to capture and visualize Electroencephalography (EEG) signals from Emotiv EPOC and BrainVision BrainAmp devices. Take a look at the project page for more information and downloads.

Example clients receiving EEG data via Open Sound Control have been implemented in vvvv and SuperCollider. The binaural sonification of EEG signals using these tools is shown in this nice video

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Sound Field Synthesis Toolbox 0.2.2 released

A new version of the Sound Field Synthesis (SFS) Toolbox is available.
Highlights of this release are:

  • the secondary source selection for focused sources in WFS works now correctly with circular arrays (see figure below)
  • the secondary_source_selection function now returns the secondary source vector x0 containing only active sources (one side effect is that only active sources are plotted, see the figure below)
  • binaural simulation of 2.5D NFCHOA
  • added compatibility for octave 3.6, note that this will be the last version that works also with octave versions <3.6

The sources of the new version can be downloaded on the usual site.
In addition a new development site for the toolbox can be found on github:
github.com/sfstoolbox/sfs.

monochromatic 2.5D WFS wave field of a focused source

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