Summary of assumptions

corresponds to the perfect alignment of the talker to the simulated orientation. The -3 dB contour lines are indicated in solid.

22

• Feedback during operation (closed loop) has not been taken into account during calibration (open loop).

• The misalignment error is acceptable for use in ±30

^o

around the front direction.

4 Applications

The first experiences trying the system have been very positive, in the sense that it gen-erates a convincing impression of being in environments different from the reproduction room, matching the expectations that talkers have about the simulated environments.

The system for real-time auralization of one’s own voice finds one of its main ap-plications in psychophysics or cross-modality research. It is possible to investigate how people perceive environments by using exclusively aural cues produced with their own voices, study the subjective effects of the acoustic environment on voice production, or study the preference of theater actors in different acoustical settings. The system described in this article is being used at the time of publication in a research project where the relation between classroom acoustical conditions and the vocal behavior of a teacher is investigated.

The system could easily be adapted for use with music instruments. In this case, it would be necessary to make the computer acoustic simulation with the directivity pattern of the desired musical instrument, and perform the calibration exactly described in this paper, but replacing the headworn microphone with a microphone to pick the sound from the instrument. However, this microphone needs to be mounted on the instrument to reject feedback and avoid the variation of the acoustic path between source and acquisition microphone during operation.

23

here described and simplifying the reproduction method, this kind of system might also find place in digital entertainment.

Acknowledgments

Thanks to Sylvain Favrot and J¨ org Buchholz for the development of the hardware ar-rangement and the LoRA toolbox, which allowed us to obtain the present system.

Thanks to Anders Christian Gade for his valuable ideas regarding calibration and quality of the system. This research is financed by the Swedish organization AFA F¨ ors¨ akring.

References

[1] V. J´ onsdottir and L. Rantala, “Nordic cooperation in the field of voice ergonomics,”

in Proceedings of the first Nordic conference of voice ergonomics and treatment, pp. 8–9, 24-25th April 2009 2009.

[2] N. Roy, R. Merrill, S. Thibeault, R. Parsa, S. Gray, and E. Smith, “Prevalence of voice disorders in teachers and the general population,” J. Speech Lang. Hear. R., vol. 47, pp. 281–93, 2004.

[3] V. Lyberg-˚ Ahlander, R. Rydell, and A. L¨ ofqvist, “Speaker’s comfort in teaching environments: Voice problems in Swedish teaching staff,” J. Voice, 2010. In press.

[4] J. Brunskog, A. Gade, G. Pay´ a-Ballester, and L. Reig-Calbo, “Increase in voice level and speaker comfort in lecture rooms.,” J. Acoust. Soc. Am., vol. 125, pp. 2072–82, april 2009.

24

[6] M. Kleiner, B. Dalenb¨ ack, and P. Svensson, “Auralization - an overview,” J. Audio Eng. Soc., vol. 41, pp. 861–861, 1993.

[7] M. Kleiner and A. Berntson, “Early frontal plane reflections preferred for talkers,”

12th ICA Proceedings (Canadian Acoustical Association, Toronto, Canada, 1986).

[8] J. Shearer and R. Torres, “Auralization studies on talker comfort,” J. Acoust. Soc.

Am., vol. 114, p. 2305, 2003.

[9] B. Dalenb¨ ack, “CATT-Acoustic, Room Acoustic Prediction Software,” 2006.

[10] D. Cabrera, H. Sato, W. L. Martens, and D. Lee, “Binaural measurement and simulation of the room acoustical response from a person’s mouth to their ears,”

Acoustics Australia, vol. 37, no. 3, pp. 98–103, 2009.

[11] A. Marshall and J. Meyer, “The directivity and auditory impressions of singers,”

Acustica, vol. 58, no. 130-140, p. 178, 1985.

[12] D. Noson, S. Sato, H. Sakai, and Y. Ando, “Singer responses to sound fields with a simulated reflection,” J. Sound Vib., vol. 232, no. 1, pp. 39–51, 2000.

[13] C. Yuen, P. Calamia, and N. Xiang, “Investigation of voice stage support: A subjective preference test using an auralization system of self-voice,” J. Acoust.

Soc. Am., vol. 121, no. 5, p. 3174, 2007.

[14] K. Stetson and J. Braasch, “Singers preferences for acoustical characteristics of performing spaces.,” J. Acoust. Soc. Am., vol. 125, p. 2586, 2009.

[15] A. Gade, “Investigations of musicians room acoustic conditions in concert halls.

Part I: Methods and laboratory experiments,” Acustica, vol. 69, pp. 193–203, 1989.

25

vol. 24, no. 3, pp. 130–138, 2003.

[17] D. McGrath, “Huron-a digital audio convolution workstation,” Presented at the 5th Australian AES regional convention, p. preprint 4023, 1995.

[18] A. Torger and A. Farina, “Real-time partitioned convolution for Ambiophonics surround sound,” in 2001 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, pp. 21–24.

[19] F. Adriaensen, “Design of a convolution engine optimised for reverb,” in LAC2006.

4th Linux Audio Conference, 2006.

[20] AES10-1991, “AES recommended practice for digital audio engineering - serial Multichannel Audio Digital Interface (MADI),” J. Audio Eng. Soc., vol. 39, no. 5, pp. 368–377, 1991.

[21] I. Bork, “Report on the 3rd Round Robin on Room Acoustical Computer Simula-tion - Part 1: Measurements,” Acta Acust. united Ac., vol. 91, no. 4, pp. 740–752, 2005.

[22] I. Bork, “Report on the 3rd Round Robin on Room Acoustical Computer Simula-tion - Part II: CalculaSimula-tions,” Acta Acust. united Ac., vol. 91, no. 4, pp. 753–763, 2005.

[23] C. L. Christensen, Odeon room acoustics program, version 9.1, user manual, in-dustrial, auditorium and combined editions, January 2008.

[24] W. Chu and A. Warnock, Detailed directivity of sound fields around human talkers.

Institute for Research in Construction, National Research Council Canada, Tech.

Rep, Canada, 2002.

26

[26] C. Porschmann, “One’s own voice in auditory virtual environments,” Acta Acust.

united Ac., vol. 87, no. 3, pp. 378–388, 2001.

[27] W. Gardner, “Efficient convolution without input-output delay,” J. Audio Eng.

Soc., vol. 43, no. 3, pp. 127–136, 1995.

[28] S. Norcross, G. Soulodre, and M. Lavoie, “Subjective investigations of inverse filtering,” J. Audio Eng. Soc., vol. 52, no. 10, pp. 1003–1028, 2004.

[29] International Organization for Standardization, “ISO-3382, Acoustics - Measure-ment of the reverberation time of rooms with reference to other acoustical param-eters,” 1997.

[30] M. Rokutanda, T. Kanamori, K. Ueno, and H. Tachibana, “A sound field sim-ulation system for the study of ensemble performance on a concert hall stage,”

Acoust. Sci. & Tech., vol. 25, no. 5, pp. 373–378, 2004.

27

Natural variations of vocal effort and comfort in simulated

In document Speakers Comfort and voice disorders in classrooms Brunskog, Jonas; Lyberg Åhlander, Viveka; Löfqvist, Anders; Garcia, David Pelegrin; Rydell, Roland (Page 121-128)