AES San Francisco 2008
Audio Product Design Event T3
Thursday, October 2, 2:30 pm — 4:30 pm
T3 - Broadband Noise Reduction: Theory and Applications
, iZotope, Inc. - Boston, MA, USAJeremy Todd
, iZotope, Inc. - Boston, MA, USA
Broadband noise reduction (BNR) is a common technique for attenuating background noise in audio recordings. Implementations of BNR have steadily improved over the past several decades, but the majority of them share the same basic principles. This tutorial discusses various techniques used in the signal processing theory behind BNR. This will include earlier methods of implementation such as broadband and multiband gates and compander-based systems for tape recording. In addition to explanation of the early methods used in the initial implementation of BNR, greater emphasis and discussion will be focused toward recent advances in more modern techniques such as spectral subtraction. These include multi-resolution processing, psychoacoustic models, and the separation of noise into tonal and broadband parts. We will compare examples of each technique for their effectiveness on several types of audio recordings.