Analysis and Design Algorithm of Time Varying Reverberator for Low Memory Applications

저전력 환경에 적합한 시간변화 잔향기의 분석 및 설계 알고리듬

  • Choi Tack-Sung (Dept., Electrical & Electronic Eng. Yonsei University) ;
  • Park Young-Cheol (Dept., Computer & Telecommunications Eng. Yonsei University) ;
  • Youn Dae-Hee (Dept., Electrical & Electronic Eng. Yonsei University)
  • Published : 2006.09.01

Abstract

Development of an artificial reverberation algorithm with low memory requirements has been an issue of importance in applications such as mobile multimedia devices. One possible solution to this problem is to embed a time-varying all-pass filter to the feedback loop of the comb filter. In this paper, theoretical and perceptual analyses of reverberators embedding time-varying all-pass filters are presented. The analyses are to iud a perceptually acceptable degree of phase variation by the all-pass filter. Based on the analyses, we propose a new methodology of designing reverberators embedding time-varying all-pass filters. Through the subjective tests, we showed that, even with smaller memory, the proposed method is capable of providing perceptually comparable sound quality to the conventional methods involving time-invariant parameters.

최근에 모바일 기기와 같은 적은 메모리를 요구하는 환경에 적합한 인공잔향기의 개발이 이슈화 되고 있다. 이러한 조건에 적합한 한가지 방법은 콤 필터의 궤환루프안에 시간변화 전대역통과 필터(APF)를 삽입하는 것이다. 본 논문에서는 시간변화 APF를 사용하는 잔향기의 이론적, 지각적 분석을 시행함으로써 지각적으로 수용 가능한 APF의 페이즈 변화량을 찾았다. 그리고 이를 바탕으로 새로운 시간변화 잔향기 설계 방법을 제안한다. 제안된 잔향기의 성능평가를 통해 제안된 잔향기가 적은 메모리를 사용하면서도 기존의 시불변 잔향기와 동일한 성능을 보임을 확인하였다.

Keywords

References

  1. Tapio Lokki and Jarmo Hiipakka, 'A Time-Variant Reverberation Algorithm for Reverberation Enhancement Systems,' Proceedings of the COST G-6 Conference on Digital Audio Effects (DAFX-01), Limerick, Ireland, December, 2001
  2. Jasmin Frenette, 'Reducing artificial reverberation algorithm requirements using time-varying feedback networks,' MS thesis, Music Eng. Tech. University of Miami
  3. Smith, J. O. 'A new approach to digital reverberation using closed waveguide networks,' In Proc. 1985 Int. Computer Music Conf., Vancouver, pp 47-53
  4. John Stautner and Miller Puckette, 'Designing multi-channel reverberators,' Computer Music Journal, Vol. 6, No. 1, pp. 52-65, Spring 1982 https://doi.org/10.2307/3680358
  5. Jot, Jean-Marc; Chaigne, Antoine, 'Digital delay networks for designing aritificial reverberators,' J. Audio Eng. Soc., Preprint 3030; Convention 90; February 1991
  6. Eric D. Scheirer, Riita Vaananen, and Jyri Huopaniemi, 'AudioBIFS: Describing audio scenes with the MPEG-4 multimedia standard,' IEEE Trans. On Multimidia, Vol. 1, No. 3, pp. 237-250, Sept. 1999 https://doi.org/10.1109/6046.784463
  7. Coding of Audio-video Objects (MPEG-4), Part 1 Systems, ISO/IEC 14496-1:2002
  8. James A. Moorer, 'About this reverberation business,' Computer Music J., Vol. 3, No. 2, pp. 13-28, 1979 https://doi.org/10.2307/3680280
  9. M. R. Schroeder, 'Natural sounding artificial reverberation,' J. Audio Eng. Soc., Vol. 10, No. 3, pp. 219-223, July 1962
  10. J. Dattorro, 'Effect design Part I: Reverberator and other filters,' J. Audio Eng. Soc., Vol. 45, No. 19, pp. 660-684, Sept. 1997
  11. J. Dattorro, 'Effect Design Part 2: Delay-line modulator and chorus,' J. Audio Eng. Soc., Vol. 45, No. 10, pp. 764-788, Oct. 1997
  12. Lauri Savioja, 'Modeling techniques for virtual acoustics,' Helsinki University of technology department, Dec, 1999
  13. Soo-Chang Pei and Chien-Cheng Tseng, 'IIR Multiple Notch Filter Design Based on Allpass Filter,' IEEE Trans. on Circuits and Systems, vol. 44, no. 2, pp. 133-136, February 1997 https://doi.org/10.1109/82.554450
  14. E.Zwicker and H.Fastl, 'Psycho-acoustics,' Springer, 1999
  15. AKI HARMA and MATTI KARJALAINEN, 'Frequency-Warped Signal Processing for Audio Applications,' J. Audio Eng. Soc., Vol. 48, No. 11, Nov, 2000
  16. Mark Kahrs, Karlheinz Brandenburg, 'Applications of Digital Signal Processing to Audio and Acoustics,' Kluwer Academic Publishers, 1998
  17. Beranek, 'Concert and Opera halls How to they sound,' Acoustical Society of America, 1996
  18. ITU-R Rec.P.84, 'Subjective listening test method for evaluating digital circuit multiplication and packetized voice systems,' 1994