The newly published toolbox is available at Matlab File Exchange as well as directly in .zip format at https://mediatech.aalto.fi/~tervos/SDMtoolbox.zip .

SDMtoolbox is a collection of matlab functions and scripts for spatial room impulse response analysis and synthesis using Spatial Decomposition method [1]. 

Visualization of the spatial room impulse response is implemented as in [2]. Other examples of the visualization have been shown for example in [3],[4] and [5]. Synthesis of the spatial room impulse response is implemented as described in [4]. Binaural synthesis follows the method in [6]. 

The toolbox processes spatial room impulse responses, measured with a microphone array. The microphone array has to be specified as a.micLocs = microphone locations in Cartesian coordinates [numberOfMics 3] and in the order [x,y,z].

The spatial impulse response should be presented in the same order as the microphone locations IR : [N numberOfMics]

For auralization, a loudspeaker array must be defined with s.lspLocs = loudspeaker in Spherical coordinates [numberOfLoudSpeaker 3] The order is Azimuth in degrees, Elevation in degrees, and Radius in meters.

There are several standard default loudspeaker setups, e.g., 5.1, in createSynthesisStruct.m, which you can use directly.

Example use cases for analysis, visualization, synthesis, and reproduction with different loudspeaker arrays or binaurally with headphones are found in:

demoCustomSetups.m 

demoDefaultSetups.m 

demoBinauralRendering.m 

To run these examples, type 

> demoCustomSetups 

> demoDefaultSetups 

> demoBinauralRendering 

in your Matlab command prompt.

This version has been tested with Matlab R2015b and R2014b. Some functions are not available in older versions. For example, parula.m and websave.m are not included before R2014b.

The demos are using examples files, which you can also directly download by copy-pasting these links to your browser 

https://mediatech.aalto.fi/~tervos/IR_living_room.mat 

https://mediatech.aalto.fi/~tervos/IR_another_living_room.mat 

https://mediatech.aalto.fi/~tervos/IR_home_control_room.mat 

https://mediatech.aalto.fi/~tervos/demoJAES/samples/Song1_CR1.mp3

References:

[1] S. Tervo, J. Pätynen, A. Kuusinen, T. Lokki "Spatial decomposition method for room impulse responses", Journal of the Audio Engineering Society, vol. 61, no. 1/2, pp. 16-27, 2013 

[2] J. Pätynen, S. Tervo, T. Lokki, "Analysis of concert hall acoustics via visualizations of time-frequency and spatiotemporal responses", In J. Acoustical Society of America, vol. 133, no. 2, pp. 842-857, 2013. 

[3] S. Tervo, J. Saarelma, J. Pätynen, P. Laukkanen, I. Huhtakallio, "Spatial analysis of the acoustics of rock clubs and nightclubs", In the IOA Auditorium Acoustics, Paris, France, pp. 551-558, 2015 

[4] S. Tervo, J. Pätynen, N. Kaplanis, M. Lydolf, S. Bech, and T. Lokki "Spatial Analysis and Synthesis of Car Audio System and Car Cabin Acoustics with a Compact Microphone Array", Journal of the Audio Engineering Society 63 (11), 914-925, 2014 

[5] P. Laukkanen "Evaluation of Studio Control Room Acoustics with Spatial Impulse Responses and Auralization", Master's thesis, Aalto University, 2014 

[6] J. Pätynen, S. Tervo, and T. Lokki, "Amplitude panning decreases spectral brightness with concert hall auralizations", In Proc. 55th Audio Eng. Soc. conference Helsinki, Finland, Aug. 27-29 2014.

1. Sakari Tervo, Jukka Pätynen, Perttu Laukkanen, Ilkka Huhtakallio, and Jukka Saarelma: Spatial analysis of the acoustics of rock clubs and nightclubs
2. Jukka Pätynen, Sakari Tervo, and Tapio Lokki: Subjective impact of concert hall acoustics
3. Henrik Möller, Jukka Pätynen, Sakari Tervo, and Tapio Lokki: Practical application and analysis of full orchestra spatial impulse responses in an opera house
4. Henna Tahvanainen and Tapio Lokki: Bass in concert halls — recent studies on the seat-dip effect
5. Jukka Saarelma: Sound field visualization using the finite-difference time-domain method and measured spatial room impulse responses
6. Antti Kuusinen and Tapio Lokki: Auditory distance perception in concert halls and the origins of acoustic intimacy
7. Tapio Lokki, Jukka Pätynen, Sakari Tervo, Antti Kuusinen, Henna Tahvanainen, and Aki Haapaniemi: The secret of the Musikverein and other shoebox concert halls 

We are really looking forward a great conference in Paris!

Check the whole program here!

References

{bibtex}virtualacoustics/ioa2015.bib{/bibtex} 

Article URL:  http://www.pnas.org/cgi/doi/10.1073/pnas.1319976111

We have several ongoing projects with this group, and the visit spawned one or two more.  We can post more details as results are published, but we discussed perception of modeling errors in room simulation, some stability issues with finite difference simulation, and how to actually extend these methods to realistic rooms.

The University (mostly the James Clerk Maxwell Building) was also a pretty cool place for physics.  On the floors, they have several forms of Maxwell's equations.  And upstairs, somewhere in the labyrinth of halls, Nobel Laureate Peter Higgs has an office.  We didn't find the actual office, but we did find a signed chalkboard:

In the end it was a pretty great trip!

{bibtex}virtualacoustics/DAFx_best_paper.bib{/bibtex}

{bibtex}virtualacoustics/aki_antti.bib{/bibtex} 

Congrats to Antti and Aki!

The awards were funded by equal contributions from the Acoustical Society of America (ASA), the International Commission on Acoustics (ICA), and ARUP.
 

This research attempts to explain why some concert halls sound better than others and what perceptual attributes contribute to the general opinion of extraordinary acoustics.  Subjective comparison of concert halls is not an easy task, because preferred acoustics depend on a number of elements. The music, the conductor, and the performance of the orchestra greatly affect the listening experience, and the contribution of the auditorium acoustics are hard to isolate with subjective surveys.

To overcome these challenges, we have developed several new technologies and techniques. The first is a loudspeaker orchestra, which standardizes the musical performance. The second is spatial sound field analysis, which allows us to evaluate the effect of the auditorium. And finally, sensory evaluation methodology borrowed from the food and wine industry allows us to evaluate the multidimensional perceptual aspects of the experience. The combination of sensory profiles and spatial analyses have resulted in an interpretation of what physical characteristics of the sound field result in the perception of great acoustics.  With these methods we have made major advances in room acoustic evaluation. More information on this research can be found here.

See also press releases in Finnish and in English.

 Here is the list of presentations/papers.

{bibtex}virtualacoustics/canada_2013.bib{/bibtex}