Bank of six parallel comb filters with built-in low-pass elements, for use as a reverberator according to the design in [Moorer2] (based on the ideas of Schroeder).
A verbatim implementation of a parallel bank of six filters of the type shown in Fig. 5 of [Moorer2]. The transfer function, T(z), of each is given by: T(z) = z-m /(1 -g2 z-m -g1g2 z-(m+1)) where the delay, m, and gains, g1 and g2, for each filter are adjusted via the Parameter Window, as summarised in the following table. Parameter Purpose "Reverb time" slider Adjusts the overall reverberation time of the bank of comb filters. From the value of this slider, denoted T (in seconds), the quantity denoted g in [Moorer2] is given by: g = 1 - 0.366/T, according to the approximate curve-fit in Fig. 13 of [Moorer2] . The six delays, m, and low-pass gains, g1, are interploated from the data listed in Table 2 of [Moorer2], which was obtained from a series of optimizations designed to match the model filter frequency reponse with measured data. Finally, the six comb gains, g2, are obtained from the value of g given above, and the six low-pass gains, g1, according to the following formula (from [Moorer2]): g2= g (1-g1). The delays are implemented using circular buffers. For more information on room acoustics and reverberation, see, for example: [Roa] p. 477-492, [Moore] p. 370-394, [Ros]p. 459-493, [Be] p. 172-222, [Zo] p. 181-205, plus various articles in [AES8] and [AES16].
