THE CHALLENGES IN PREPARING THE STIMULI TO BE USED IN SUBJECTIVE EVALUATION OF IMPACT SOUND INSULATION

This paper offers an overview of the general guidelines related to the preparation of the sound stimuli to be used in listening tests devised for subjective evaluation of impact sound insulation properties of building elements. Different approaches are presented to both collecting the sound samples and to converting them into a form that can be used for carrying out the listening tests. The advantages and the limitations of the presented approaches are discussed. Besides general guidelines, an example is given on the preparation procedure of impact stimuli in the form of footsteps sound as a result of walking on a typical floor, as heard in the room below. The variables taken into account are floor construction, type of footwear worn by the walker, the weight of the walker, and walking tempo. For the recording part of the procedure, the specifics are given on the recording setup and the acoustical conditions in the recording room. The conversion of raw sound samples into a form suitable for reproduction over headphones and loudspeakers is described as well. Preliminary analysis of the collected sound samples is presented, regarding the overall level and loudness, as well as the spectral content, with respect to the considered variables