Approximating Measured Reverberation Using A Hybrid Fixed/Switched Convolution Structure
|Title||Approximating Measured Reverberation Using A Hybrid Fixed/Switched Convolution Structure|
|Publication Type||Conference Paper|
|Year of Publication||2010|
|Authors||Lee, K. S., N. Bryan, and J. S. Abel|
|Conference Name||Proc. 13th Int. Conf. Digital Audio Effects (DAFx-10)|
|Conference Location||Graz, Austria|
An efﬁcient reverberator structure is proposed for approximatingmeasured reverberation. A ﬁxed convolution matching the early portion of a measured impulse response is crossfaded with a switched convolution reverberator drawing its switched convolution section from the late-ﬁeld of the measured impulse response. In this way, the early portion of the measured impulse response is precisely reproduced, and the late-ﬁeld equalization and decay rates efﬁciently approximated. To use segments of the measured impulse response, the switched convolution structure is modiﬁed to include a normalization ﬁlter to account for the decay of the late-ﬁeld between the nominal ﬁxed/switched crossfade time and the time of the selected segment. Further, the measured impulse response late-ﬁeld is extended below its noise ﬂoor in anticipation of the normalization. This structure provides psychoacoustically accurate synthesis of the measured impulse response using less than half a second of convolution, irrespective of the length of the measured impulse response. In addition, the structure provides direct control over the equalization and late-ﬁeld frequency dependent decay rate. Emulations of EMT 140 plate reverberator and marble lobby impulse responses are presented.