A Subjective Related Measure of Airborne Sound Insulation

Abstract

In many practical cases, the objective measures of airborne sound insulation using standard procedures do not agree with subjective assessments. This paper describes a calculation scheme based on the loudness level linked to the specific fluctuation strength and yields a weighted normalized loudness level difference. Evidence has been presented through a subjective evaluation that the model can be considered to be a link between an objective and subjective evaluation. The stimuli offered in the experiment were electronically filtered sound samples representing the sound insulation of interest. Steady-state and non-steady state signals are used as stimuli. To differentiate the signal in terms of psychoacoustic measures, investigations of music type signals were focused on specific fluctuation strength. An assessment of identical airborne sound insulation experimental results has shown that steady-state signals were assessed to be significantly quieter than non-steady-state signals, which also yield greater specific fluctuation strength. As expected, sound insulation was judged differently for different sound samples. A simple level difference is shown not to exhibit the effects of a given signal to the frequency-dependent airborne sound insulation curve. This study supports findings in the literature that airborne sound insulation performance is significantly dependent on what type of sound signal is used.