Comparative Study of Optimal Design Strategies of Reverberators

摘要

Artificial reverberator is a key element in spatial audio reproduction. This paper compares various optimal designstrategies of artificial reverberators for room response simulation. From the comparison, it is hoped that guidelinesfor design of natural-sounding reverberators can be found. Infinite impulse response (IIR) filters such as allpass filters orcomb filters are used as building blocks for the design. Early reflections of room responses are modeled by three differentapproaches: the traditional image method, the exponential truncation method, and network approximation method. On theother hand, combested allpass filter networks are exploited for modeling late reverberations, with parameters predeterminedby a genetic algorithm (GA)-based procedure. Up/down-sampling and spectral band replication (SBR) techniquesare also employed to save memory storage and recover the lost high frequency portion of the reverberation. Subjectivelistening tests were conducted to compare the proposed artificial reverberator modules. The test results revealedthat the reverberator in which early reflections are modeled by network approximation and late reverberations are modeledby combested allpass filter network is superior in delivering natural-sounding reverberation among all methods.