Q-factor modification for low-frequency room modes

摘要

Low frequency normal modes of an enclosed soundfield introduce unwanted frequency, spatial and temporal artefacts to reproduced electroacoustic signals. A novel control approach has been reported based on an analytical modal decomposition, using a low frequency soundfield model in a one-dimensional environment formed from the sum of a number of second order IIR filter sections. In this paper, these techniques are applied to the low frequency resonances of a three dimensional test room. It is shown that significant reductions in modal Q and corresponding reductions in modal decay times may be achieved, leading to smaller low-frequency soundfield variance and decreasing audibility of time-domain modal artefacts.