Further Extensions

International Standard Book Number — Click for https://mathworld.wolfram.com/ISBN.html

Click for https://ccrma.stanford.edu/~jos/mdft/Matrices.html

A feedback comb filter is made from a delay line by scaling its output signal by some coefficient and summing that with the delay-line input signal. — Click for https://ccrma.stanford.edu/~jos/pasp/Feedback_Comb_Filters.html

Click for https://ccrma.stanford.edu/~jos/pasp/Feedback_Delay_Networks_FDN.html

The impulse response of a system is its output signal in response to the impulse signal. For discrete time (digital) systems, the impulse is a 1 followed by zeros. In continuous time, the impulse is a narrow, unit-area pulse (ideally infinitely narrow). — Click for https://ccrma.stanford.edu/~jos/filters/Impulse_Response_Representation.html

Click for https://ccrma.stanford.edu/~jos/pasp/Feedback_Delay_Networks_FDN.html

Reverberation is the sound created by many echoes blending together, such as you hear when you clap your hands together in an acoustically 'live' room. — Click for https://ccrma.stanford.edu/~jos/pasp/Artificial_Reverberation.html

A filter in the audio signal processing context is any operation that accepts a signal as an input and produces a signal as an output. Most practical audio filters are linear and time invariant, in which case they can be characterized by their impulse response or their frequency response. — Click for https://ccrma.stanford.edu/~jos/filters/What_Filter.html

Click for https://ccrma.stanford.edu/~jos/filters/Allpass_Filters.html

A comb filter is made from a delay line using a linear combination of its input and output signals. — Click for https://ccrma.stanford.edu/~jos/pasp/Comb_Filters.html

Further Extensions

Schroeder's original structures for artificial reverberation were comb filters and allpass filters made from two comb filters. Since then, they have been upgraded to include specific early reflections and per-sample air-absorption filtering (Moorer, Schroeder), precisely specified frequency dependent reverberation time (Jot), and a nearly independent factorization of ``coloration'' and ``duration'' aspects (Jot). The evolution from comb filters to feedback delay networks (Gerzon, Stautner, Puckette, Jot) can be seen as a means for obtaining greater richness of feedback, so that the diffuseness of the impulse response is greater than what is possible with parallel and/or series comb filters. In fact, an FDN can be seen as a richly cross-coupled bank of feedback comb filters whenever the diagonal of the feedback matrix is nonzero. The question then becomes what aspects of artificial reverberation have not yet been fully addressed?

Further Extensions

``Physical Audio Signal Processing'', by Julius O. Smith III, W3K Publishing, 2010, ISBN 978-0-9745607-2-4 Copyright © 2024-06-28 by Julius O. Smith III Center for Computer Research in Music and Acoustics (CCRMA), Stanford University

``Physical Audio Signal Processing'', by Julius O. Smith III, W3K Publishing, 2010, ISBN 978-0-9745607-2-4
Copyright © 2024-06-28 by Julius O. Smith III
Center for Computer Research in Music and Acoustics (CCRMA), Stanford University