Finding the Audibility of the Temporal Decay Rate of a Low Frequency Room Mode

A listening test system designed to measure the threshold of audibility of the decay time of low frequency resonances is described. The system employs the Parameter Estimation by Sequential Testing (PEST) technique and the listening test is conducted on calibrated headphones to remove factors associated with the listening environment. Program signal, replay level, and resonance frequency are believed to influence decay time threshold. A trial listening test shows that the system reveals realistic results but the temporal resonance modelling filter requires some adjustment to remove audible non-modal cues. The system is robust but transducer limitations still affect the test at low frequencies and high replay levels. Factors for a future large-scale listening test are refined. Early indications are that temporal decay thresholds rise with reduced frequency and SPL.