Equalization of Multichannel Acoustic Systems in Oversampled Subbands

• Published in: IEEE transactions on audio, speech, and language processing Vol. 17; no. 6; pp. 1061 - 1070
• Main Authors: Gaubitch, N.D., Naylor, P.A.
• Format: Journal Article
• Language: English
• Published: Piscataway, NJ IEEE 01.08.2009; Institute of Electrical and Electronics Engineers
• Subjects: Acoustic applications; Acoustic measurements; Acoustic noise; Acoustic signal processing; Acoustics; Applied sciences; Computational efficiency; Delay; Dereverberation; Detection, estimation, filtering, equalization, prediction; Equalization; Estimates; Exact sciences and technology; Filters; Frequency estimation; Impulse response; Information, signal and communications theory; Microphone arrays; Miscellaneous; Multichannel; multichannel equalization; multirate audio processing; Position measurement; Signal and communications theory; Signal processing; Signal, noise; Sound filters; Speech processing; Telecommunications and information theory; Transfer functions; Subband decomposition; Audio signal processing; Dereverberation; Multirate system; Oversampling; Acoustic signal processing; Equalization; Noise measurement; Digital filter; Accuracy; Pulse response; Signal processing; Finite impulse response filter; multichannel equalization; Transfer function; multirate audio processing; Multiple channel; Minimum phase
• ISSN: 1558-7916; 1558-7924
• DOI: 10.1109/TASL.2009.2015692

Equalization of room transfer functions (RTFs) is an important topic with several applications in acoustic signal processing. RTFs are often modeled as finite-impulse response filters, characterized by orders of thousands of taps and non-minimum phase. In practice, only approximate estimates of the actual RTFs are available due to measurement noise, limited estimation accuracy, and temporal variation of source-receiver position. These issues make equalization a difficult problem. In this paper, we discuss multichannel equalization with focus on inexact RTF estimates. We present a multichannel method for the equalization filter design utilizing decimated and oversampled subbands, where the full-band acoustic impulse response is decomposed into equivalent subband filters prior to equalization. This technique is not only more computationally efficient but also more robust to impulse response inaccuracies compared with the full-band counterpart.