SOFiA Sound Field Analysis Toolbox

Posted on 13. November 2011 by Sascha Spors

Spherical microphone arrays and sound field decomposition using spherical harmonics is a well established technique for the analysis of sound fields, room acoustics or spatial audio recording applications. The Sound Field Analysis Toolbox (SOFiA) provides a MATLAB toolbox for the analysis of sound fields using data from spherical microphone arrays.  It is freely available under the GNU GPL v3 license. For the evaluation of SOFiA, exemplary datasets from a VariSphear scanning array system are available under the Creative Commons license.

SOFiA can be downloaded here http://code.google.com/p/sofia-toolbox/

An overview of the SOFiA processing chain as well as a closer discussion of selected details can be found in the paper

B. Bernschütz, C. Pörschmann, S. Spors, and S. Weinzierl. SOFiA – Sound field analysis toolbox. In International Conference on Spatial Audio, Detmold, Germany, November 2011. [PDF]

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Using the RME MADIface on Linux

Posted on 5. November 2011 by matthias.geier

If you want to use the RME MADIface on Linux, it probably doesn’t work right away.

The latest version of ALSA (1.0.24) – which is probably already installed on your computer – is from January 2011. However, there was a lot of activity and bug-fixing going on since February. So you won’t have all the good stuff and a few things won’t work at all.

Especially, we couldn’t use the sound card in slave mode, and even in master mode a few sample rates just didn’t work. And, what’s really sad, the hdspmixer didn’t work.

But fear not, there is still hope!

That’s what we did:

Download the newest and freshest alsa-driver package from here: http://www.alsa-project.org/snapshot/.

Extract the package somewhere, and compile the thing:

tar xvjf /path/to/alsa-driver-1.0.24.88.gb41c8.1877.ga1e0a.tar.bz2
cd alsa-driver-1.0.24.88.gb41c8.1877.ga1e0a
./gitcompile

You may need a few development packages from your Debian (or whatever you are using) repository (maybe build-essentials, autoconf, …).

And then, as root, install everything:

make install

And that’s it! After re-booting (or restarting the relevant services if you know what those are …) everything should work. You can set the sync-options with alsamixer and you can also use the hdspmixer.

Of course, all this will be obsolete once the new ALSA version 1.0.25 (or whatever comes after 1.0.24) will be released as Debian (or whatever you are using) package.

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Audio examples for paper Ahrens, Spors: “Two Physical Models for Spatially Extended Virtual Sound Sources” 131st Convention of the AES, 2011

Posted on 20. October 2011 by Jens Ahrens

Below you will find audio examples for the paper

Jens Ahrens and Sascha Spors: “Two Physical Models for Spatially Extended Virtual Sound Sources”, 131st Convention of the AES, New York City, NY, USA 2011 [ pdf ]

Download the zipped package, which contains the input signal as well as the signals evoked by two line sources (i.e., 2.5D approximations of two planar sources) vibrating in complex modes. One source has length 4 m and the other one has length 0.5 m. All other parameters are explained in Sec. 4.2 of the paper. You may listen with headphones as well as with loudspeakers since the audio examples give only a first impression of the results and are not formal.

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Timetable for the ICSA 2011 is Online

Posted on 20. October 2011 by Sascha Spors

The timetable for the International Conference on Spatial Audio 2011 in Detmold/Germany is now online:

ICSA 2011 Timetable (PDF)

The conference emphasizes the scientific and technical aspects of spatial audio, but a number of workshops and presentations will be devoted to the artistic and esthetic possibilities and challenges as well.

In addition to five structured sessions on various spatial audio topics, the conference will feature installations of WFS + Height, Auro-3D, Binaural and Higher-order Ambisonic systems. During a three-day recording session last week totalling more than 140 microphone signals, we have recorded several chamber music ensembles simultaneously for all those methods and will offer conference participants a first-hand opportunity for comparison.

Complementing the two fixed WFS installations available in Detmold, an additional temporary 40-speaker setup will be rigged for WFS and Higher-order Ambisonics reproduction, and one seminar room will be equipped for 9+2 channel Auro-3D playback.

Registration is now open, and I’d be delighted to see you in Detmold in November!

 

This announcement has been provided by Jörn Nettingsmeier

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Release 0.3.2 of the SoundScape Renderer

Posted on 7. September 2011 by Sascha Spors

The new release 0.3.2 (Spinet) of the SoundScape Renderer (SSR) is available for download. This release contains  a number of bugfixes and includes the source code of the Android SSR remote control. Thanks to all of you who have reported bugs. We encurage all users to send bug reports, usage reports and feature requests to SoundScapeRenderer@telekom.de. You can also send us your (example) scenes or content you have produced with the SSR. First examples provided by Stefan Greuel and Philipp Stade can be downloaded here.

The SSR development team

 

The SoundScape Renderer (SSR) is a versatile software framework for real-time spatial audio rendering. The modular system architecture allows the use of arbitrary rendering methods, e.g. Wave Field Synthesis, Higher-Order Ambisonics, Vector Base Amplitude Panning and binuaral techniques. The SSR is currently available for Linux and OS X. It has been released as open source software under the GPL.

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CfP – International Conference on Spatial Audio 2011

Posted on 6. July 2011 by Sascha Spors

The International Conference on Spatial Audio 2011 takes place from November 10 to 13 at Detmold University of Music.  This expert‘s summit will examine current systems for multichannel audio reproduction and complementing recording techniques, and discuss their respective strengths and weaknesses.  Wavefield synthesis systems, a higher-order Ambisonics array, as well as 5.1/7.1 installations in diverse acoustic environments will be available for comparative listening tests during the conference.  Structured plenary talks, paper and poster sessions will revisit fundamentals and present latest research.  A series of workshops will be dedicated to practical implementations of spatial sound capture and playback methods, and their esthetic and psychoacoustical implications for music perception.  Concerts that include music specially arranged for the conference will let you experience various spatial sound systems in “live” conditions.

Call for papers
Your contributions are welcome, either as presentations, posters, or workshops. Submissions will undergo a review process, and accepted contributions will be published in the conference proceedings.

The conference language is English.

We are planning structured sessions on the following topics:

  • Multichannel stereo
  • Wave field synthesis
  • Higher-order Ambisonics / spherical acoustics
  • 3D systems
  • Binaural techniques

 

The submission site is open now. Contributions can be submitted here.
Closing date is July 31st, 2011.

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Videos of our talks given at ICASSP 2011

Posted on 30. June 2011 by Sascha Spors

Our and most of the other talks given at the International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2011 in Prague have been recorded, processed and uploaded to this portal.  In particular you can find our talks on

We are not responsible for the annotation 🙂

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Audio examples for the paper “Efficient Range Extrapolation of Head-Related Impulse Responses by Wave Field Synthesis Techniques” presented at ICASSP 2011

Posted on 24. May 2011 by Sascha Spors

These post provides supplementary binaural audio examples for the paper

S. Spors and J. Ahrens. Efficient range extrapolation of head-related impulse responses by wave field synthesis techniques. In IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), May 2011.

The audio samples have been generated by convolving a monotic speech sample by the respective left and right head-related impulse responses (HRIRs). Furthermore, a headphone compensation filter for the AKG K601 headphone has been applied. Hence, best results are achieved when listening with this headphone model. The effect of distance can be perceived best for a source at the side due to the underlying psychoacoustic properties of distance perception. Our free database of head-related impulse responses (HRIRs) has been used for the audio examples.

Download the audio examples as zip-archive here. The file name conventions are given in the file README.txt.

Note that these examples are intended for use with headphones!

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Free Database of Head-Related Impulse Response Measurements

Posted on 13. May 2011 by Sascha Spors

We have measured a set of horizontal plane Head-Related Impulse Response (HRIR). The impulse responses were acquired in an anechoic chamber using a KEMAR manikin at four different loudspeaker distances – 3m, 2m, 1m and 0.5m – reaching from the far field to the near field. The loudspeaker was positioned at ear height and the manikin was rotated with a high-precision stepper motor in one degree increments. Besides the raw HRIRs also datasets are available which have been compensated for the use with specific headphone models.

All measurements are freely available for download under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license. The measurements are described in detail in the companion Wiki or in the AES Engineering Brief

Hagen Wierstorf, Matthias Geier, Alexander Raake and Sascha Spors, A Free Database of Head-Related Impulse Response Measurements in the Horizontal Plane with Multiple Distances, 130th Convention of the AES, London, May 2011.

You can download the database in various formats here.

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New release of the SoundScape Renderer available

Posted on 4. May 2011 by Sascha Spors

We have worked hard in the last months to fix serveral bugs and on various improvements of the SoundScape Renderer (SSR). The current release 0.3.1 includes:

  • OS X 10.6 port of the SSR
  • Android remote control (as .apk)
  • Pure Data (Pd) patches for remote-controlling the SSR
  • “Binaural Playback Renderer”
  • current audio scene can now be saved (have a look in the “file” menu)
  • several bugfixes
  • improvements in the build system
  • improvements in new (multithreaded) renderer architecture

The current release 0.3.1 can be downloaded in the files section of the SSR development page.

Please use SoundScapeRenderer@telekom.de for questions, feedback and bug reports.

The SSR development team

The SoundScape Renderer (SSR) is a versatile software framework for real-time spatial audio rendering. The modular system architecture allows the use of arbitrary rendering methods, e.g. Wave Field Synthesis, Higher-Order Ambisonics, Vector Base Amplitude Panning and binuaral techniques. The SSR is currently available for Linux and OS X. It has been released as open source software under the GPL.

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