HpTF compensation filters for KEMAR available

Headphone transfer function (HpTF) compensation filters of a KEMAR 45BA with large ears for several headphone types are now available at:

hptf-compensation-filters

The compensation filters are released complete with HpTF measurements and the Matlab code the filters have been calculated with. They are fit to use with our free database of BRIRs of our 64-channel loudspeaker array.

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Two!Ears Auditory Model 1.1 Released

A new version of our software framework was published today, please go to the download section and have a look at the installation guide in order to try it out.

Besides lots of bug fixes, the main new features of this release are:

Binaural simulator:
* Works now under Matlab 2015b
New processors in the Auditory front-end:
* precedence effect processor
* MOC feedback processor
New knowledge source in the Blackboard system:
* Segmentation knowledge source
* Deep neural-network based localisation knowledge source
* Coloration knowledge source
* Localisation knowledge source for evaluating spatial audio systems
New Database entries:
* Results from listening test on coloration in wave field synthesis
New Examples:
* DNN-based localisation under reverberant conditions
* Segmentation with and without priming
* (Re)train the segmentation stage
* Prediction of coloration in spatial audio systems
* Prediction of localisation in spatial audio systems

 

TWO!EARS is a project funded by the Seventh Framework Programme (FP7) of the European Commission, as part of the Future Emerging Technologies Open Programme “Challenging current thinking” (call FP7-ICT-2013-C).

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Release 0.2.0 of the Sound Field Toolbox for Python

Release 0.2.0 of our Sound Field Toolbox for Python is available. The Python port of the Sound Field Synthesis toolbox features the calculation of the synthesized sound field for various sound reproduction methods for the monofrequent case. Functionality for visualization of sound fields, as well as a set of auxiliary functions is included. The documentation gives you a first glance on its functionality.

Release 0.2.0 features

  • Ability to calculate and plot particle velocity and displacement fields
  • Several function name and parameter name changes
  • Several refactorings, bugfixes and other improvements

Installation instructions can be found here.

particle_displacement_line_sourceparticle_displacement_plane_wave

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Talk: Simulating Room Acoustics

Sascha Spors gave a talk on the simulation of ear signals using the binaural simulator of the two!ears project. The simulator is available as open source, as well as the two!ears auditory model.

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Paper: Sound Field Synthesis of Virtual Cylindrical Waves using Circular and Spherical Loudspeaker Arrays

The paper Sound Field Synthesis of Virtual Cylindrical Waves using Circular and Spherical Loudspeaker Arrays was presented at the 138th Convention of the Audio Engineering Society in Warsaw, Poland. The presentation slides and the MATLAB script used for the simulations are available for download. The latter has to be used with the SFS toolbox.

AES138_blog

Errata
Eq. (19) $$ D_\text{3D}(\alpha_0,\beta_0,\omega) = \frac{2}{{r_0}^2} \sum_{n=0}^{\infty} \sum_{m=-n}^{n} \frac{\color{RoyalBlue}{i^{m-n+1}} \mathring{S}_{m}(\omega)}{\tfrac{\omega}{c} h_{n}^{(2)}(\tfrac{\omega}{c}r_0)} Y_{n}^{m}(\tfrac{\pi}{2},0)^\ast Y_{n}^{m}(\beta_0,\alpha_0) $$
Eq. (20) $$ D_\text{3D,ls}(\alpha_0,\beta_0,\omega) = \frac{1}{2{r_0}^2} \sum_{n=0}^{\infty} \sum_{m=-n}^{n} \frac{\color{RoyalBlue}{i^{m-n}} H_{m}^{(2)}(\frac{\omega}{c}r_\text{ls})}{\tfrac{\omega}{c} h_{n}^{(2)}(\tfrac{\omega}{c}r_0)} Y_{n}^{m}(\tfrac{\pi}{2},\alpha_\text{ls})^\ast Y_{n}^{m}(\beta_0,\alpha_0) $$
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Paper: Modal Bandwidth Reduction in Data-based Binaural Synthesis including Translatory Head-movements

The paper Modal Bandwidth Reduction in Data-based Binaural Synthesis including Translatory Head-movements was presented at the 41st German Annual Conference on Acoustics (DAGA) in Nuremberg, Germany. Feel free to download the presentation slides.

Ear signals for different head positions were simulated by filtering the individual plane wave components with the corresponding head-related transfer functions (HRTFs).

circular harmonics order $M = 23$, number of plane waves (HRTFs) $N = 360$
$r=0.0$
$r=0.1$
$r=0.2$
$r=0.3$
$\phi=0$
$\phi=30$
$\phi=60$
$\phi=90$
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Sound Field Synthesis Toolbox 2.0.0 released

A new release of the Sound Field Synthesis Toolbox for Matlab/Octave is available. The highlights of the new version include support of the SOFA file format for HRIRs and BRIRs, usage of custom grids for sound field simulations, and a plotting routine for 3D sound fields.

This new version of the Toolbox enables you to listen to a binaural simulation of our 64-channel loudspeaker array at the University of Rostock.

sfs-2.0.0-2

Download the SFS Toolbox 2.0.0, PDF documentation and have a look at the tutorial on github how to use it.

NOTE: this version of the SFS Toolbox is no longer compatible with the old irs mat-file based file format for HRIRs and BRIRs. If you want still to use these one, you have to use SFS Toolbox 1.2.0, which is the latest version released using the old file format.

NEWS:

- add support for SOFA
- add SOFA convention SimpleFreeFieldHRIR
- add SOFA convention MultiSpeakerBRIR
- calculate integration weights (x0(:,7)) of secondary sources based on their
distances to their neighbours
- add rounded-box as new loudspeaker array geometry
- fix bugs in local sound field synthesis time domain implementation
- speedup local sound field synthesis processing by fewer calls to
delayline()
- add heuristic to find a good local wave field synthesis pre-filter
- loudspeaker geometry can now be read from a SOFA file
- now custom grids can be used during sound field simulations
- add 3D plot routine
- change plot_sound_field(P,x,y,z) to plot_sound_field(P,X,Y,Z)
- normalization of sound field now only happens in plot_sound_field(); this
comes with the new config option conf.plot.normalisation
- remove interaural_level_difference() and interaural_time_difference()
- change default config setting conf.ir.usehcomp to false
- lots of small bug fixes

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Paper: Synthesis of a sound field scattered by a virtual object using near-field compensated higher-order Ambisonics

At the upcoming IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA), we will present the paper

Hahn, N.; Spors, S.: “Synthesis of a Sound Field Scattered by a Virtual Object Using Near-field Compensated Higher-order Ambisonics”. In Proc. of the IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, New Paltz, NY, USA.

The poster can be found here.

We have also prepared some listening examples. A dynamic scenario was considered where the direct sound is obstructed by a virtual object moving from left to right. The ear signals were simulated for the central listening position of a circular loudspeaker array. The driving signals of the loudspeakers were filtered with head-related impulse responses. Please use headphones.

nfchoa_virtual_scatterer_earsignals_config

sound-hard scatterer sound-soft scatterer
speech
castanets
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Sound Field Synthesis Toolbox for Python

We are proud to announce the first release 0.1.0 of the Sound Field Synthesis toolbox for python. The toolbox is purely written in Python. It currently features the calculation of the synthesized sound field for various sound reproduction methods for the monofrequent case. Functionality for visualization of sound fields, as well as a set of auxiliary functions is included. The documentation gives you a first glance on its functionality.

You can get the toolbox in two ways

  • Using the Python packet manager pip
    pip install sfs
  • Clone the latest snapshot from the Github
    git clone https://github.com/sfstoolbox/sfs-python.git
    cd sfs-python
    python setup.py develop --user

The toolbox is under active development. New features and functionality will be added in future releases. Contributions, comments, suggestions and feature requests are very welcome.

circular_ps_wfs_25d_point

 

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Paper: Non-smooth secondary source distributions in Wave Field Synthesis

The paper Non-smooth secondary source distributions in Wave Field Synthesis by Sascha Spors, Frank Schultz and Hagen Wierstorf disusses artifacts arising from edges in rectangular loudspeaker arrays. The Python scripts used to compute the figures in the paper can be downloaded on github. The presentation (German) given at the German Annual Conference on Acoustics (DAGA) 2015 can be viewed on speakerdeck.

DAGA_non_smooth_pw

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