Subjective Evaluation of Directional Properties of Loudspeaker Systems with the Analog and Digital Crossover Networks

摘要

The aim of this study was to determine the way in which loudspeaker systems with the analog and digital crossover networks were subjectively evaluated. The object of the study were two loudspeaker systems, differing in both the position of speakers on the front panel of enclosure and configuration of the crossover networks: 2.5-way and 3-way systems with the slope of frequency response of 12 dB/octave in the cut-off regions. The investigations were conducted for 5 angles from the front hemisphere in the horizontal plane. Test signals were fragments of music and speech. The recordings of these signals were conducted in an anechoic chamber using an artificial head and then presented to the listeners through headphones. Five normally-hearing listeners aged 18-50 years took part in the experiment. Listening tests were carried out in two stages. In the first stage listeners were listening to test signals grouped in triads and their task was to identify pairs of signals the most and the least similar to each other. In the second stage a parametric evaluation was performed. It consisted in assigning five numbers, corresponding to the intensity of the attribute of perception space (evaluated on a scale of 0-10) to each of test signals. The attributes of perception space included: sharpness, clearness, fullness, lack of distortions and loudness. Using the method of multidimensional scaling and correlation analysis it was possible to relate a particular dimension of the multidimensional space to the attributes of the perception space. It was found that the intrinsic attributes responsible for the subjective evaluation of loudspeaker systems with the analog and digital crossover network were sharpness, clearness and loudness.