spatialaudio.net

For everyone who is wondering if we are still being active: YES.
We have now the spatialaudio.net blog together with our colleagues from the university of Rostock.

spatialaudio.net

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.

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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A maintenance release of the SoundScape Renderer (SSR) is available. The major changes are

  • several bugfixes and improvements
  • fixed Polhemus tracker support on MacOSX
  • introduced “reference offset” for tracking people within loudspeaker arrays

The new release 0.3.4 (“Pianoforte”) can be downloaded here for Linux and OS X platforms. Note that this will be the last release which bases on the single threated signal processing core. Watch out for our new multithreaded architecture that is currently being developed. Future releases of the SoundScape Renderer will be available on github and will be announced on spatialaudio.net.

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New Affiliation

After working seven years at the Quality and Usability Lab of Deutsche Telekom Laboratories I take on a fresh challenge. I am now heading the Signal Theory and Digital Signal Processing group as professor at the Institute of Communications Engineering of the University Rostock. I will continue my work in the field of spatial sound capture and reproduction.

Sascha Spors

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

  • simulation of monochromatic wave fields for 2.5D NFCHOA (see the figure below)
  • simulation of monochromatic wave fields for 2.5D SDM
  • NFCHOA simulations now also work under Octave

In addition we fixed some bugs and made some minor changes, especially

  • fixed direction of plane waves and point sources for NFCHOA time domain simulations
  • changed syntax for wave_field_* and driving_* functions:
    xs,f,src => xs,src,f
    xs,L,src => xs,src,L
    xs,L,f,src => xs,src,f,L

The sources of the new version can be downloaded on the usual site.

monochromatic 2.5D NFCHOA wave field

This post contains additional material for the paper

Sascha Spors and Hagen Wierstorf. On the Implementation of Range Extrapolation of Head-Related Impulse Responses by Virtual Sound Field Synthesis using Integer Delays. In German Annual Conference on Acoustics (DAGA), March 2012.

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We are happy to announce the first public and open source release of our Sound Field Synthesis (SFS) Toolbox. It is a toolbox for Matlab/Octave to numerical simulate different SFS methods like Wave Field Synthesis (WFS) or higher order Ambisonics (HOA). It provides a variety of functions to reach mono-frequent and spatio-temporal impulse responses for different array geometries and driving functions.

You can find the sources and documentation on the corresponding SFS Toolbox site.

Note that there are two bugs in the current version, and one of them will prevent you from plotting the results. Have a look at the corresponding wiki page how to fix this.

To demonstrate some of the features of the toolbox, below an image of a mono-frequent plane wave synthesized using WFS and a linear loudspeaker array is shown. The different colors of the speakers at the ends of the array visualize the applied tapering window.

plane wave, synthesized using WFS and a linear loudspeaker array

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We have presented a paper at the 5th International Symposium on Communications, Control, and Signal Processing. It discusses the influence of spatial bandlimitation in modal beamforming when used as plane wave decomposition for binaural synthesis. Besides the instrumental measures given in the paper/presentation you can also download a series of listening examples. The samples have been computed for the parameters described in the paper. The maximum order N of the spherical harmonics expansion has been varied, as well as the head rotation (incidence angle of the virtual source). As source material noise bursts, speech and castanets have been used. The examples are provided as binaural sound files optimized for the AKG K-601 headphone. The file names encode the conditions and incidence angle.

Download the listening examples by following this link

 

The full reference to the paper is

S. Spors and H. Wierstorf. Evaluation of perceptual properties of phase-mode beamforming in the context of data-based binaural synthesis. In IEEE-EURASIP International Symposium on Control, Communications, and Signal Processing, May 2012.

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At the 132nd Convention of the Audio Engineering Society we presented the paper

S. Spors, H. Wierstorf, and M. Geier. Comparison of modal versus delay-and-sum beamforming in the context of data-based binaural synthesis. In 132th AES Convention. Audio Engineering Society (AES), April 2012.

The presentation slides are available here.

This post provides listening examples for the comparison of modal (MB) and delay-and-sum (DSB) beamforming when used as plane wave decomposition for binaural synthesis. The stimuli have been computed as described in the paper for spatially continuous and sampled spherical microphone arrays. Additionally for modal beamforming the maximum order of the spherical harmonics has been varied in the spatially continuous case. As source material noise bursts, speech and castanets have been used. The examples are provided for various incidence angles, as stereo sound files optimized for the AKG K-601 headphone. The file names encode the conditions and incidence angle.

Download the samples for

by following the links.

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