The Role of Modal Excitation in Colorless Reverberation

Abstract

A perceptual study revealing a novel connection between modal properties of feedback delay networks (FDNs) and colorless reverberation is presented. The coloration of the reverberation tail is quantified by the modal excitation distribution derived from the modal decomposition of the FDN. A homogeneously decaying allpass FDN is designed to be colorless such that the corresponding narrow modal excitation distribution leads to a high perceived modal density. Synthetic modal excitation distributions are generated to match modal excitations of FDNs. Three listening tests were conducted to demonstrate the correlation between the modal excitation distribution and the perceived degree of coloration. A fourth test shows a significant reduction of coloration by the colorless FDN compared to other FDN designs. The novel connection of modal excitation, allpass FDNs, and perceived coloration presents a beneficial design criterion for colorless artificial reverberation.

Modal Excitation in Feedback Delay Networks

“…Our prior work introduced a modal decomposition technique for FDNs [8], representing the FDN as a sum of complex onepole resonators, or modes. These modes find utility in system estimation [9], oscillation analysis [10], [11], resonance excitation optimization [12], [13], matching desired room modes [14], and enhancing the design of coupled room reverberators [15]- [17].…”