# Validation of the Developed Psychoacoustic Model for Sound Quality Valuation of Washing Machines
## 4 Conclusions  
The evaluation of the acoustic quality of household appliances entails the comprehensive evaluation of the sounds emitted by these devices and their perception by users. In the process of sound evaluation, the basic tool for determining psychoacoustic quantities is a binaural measuring device, also known as an artificial head. Questionnaire methods are used to discover the opinions of users of individual devices, where respondents evaluate the sounds of these devices. In previous research [12], a correlation was found between the measured psychoacoustic parameters and the results of the questionnaire survey. The  
Figure 4: The process flowchart of validation of the developed psychoacoustic model for sound quality valuation of washing machines. result was the determination of weighting factors for individual psychoacoustic variables. By applying these weighting factors to the measured values, it is then possible to determine the quality of sounds even without a questionnaire survey. The validation process of the developed model was carried out on three top-loading washing machines. After determining the psychoacoustic quantities, the ranking of washing machines was compiled based on their sounds. Subsequently, the sound quality indices for these washing machines were determined with the already applied weight factors for individual psychoacoustic variables, and the ranking of the sounds of these washing machines was reconstructed. A questionnaire survey was conducted to verify the evaluation of sound quality based on the developed model and the application of weighting factors. Based on the questionnaire survey, the ranking of the sound quality of washing machines was again calculated. The final step of the validation was a comparison of the results of the quality ranking of washing machine sounds, based on a questionnaire survey and the application of weighting factors to the measured psychoacoustic parameters. The results show an almost perfect match in the ranking of sounds based on respondents' opinions and through the sound quality index. The ordinal correlation was different in the FILL mode, which was due to the appearance of an atypical tonal sound, which was not considered in the developed psychoacoustic model for evaluating the quality of washing machine sounds. The experimental evaluation conducted in this work follows a widely used methodology, inspired by regulatory guidelines for statistical data analysis in analytical method validation, to optimize the number of assays and meet the validation criteria requirements. The agreement in determining the ranking was also confirmed by [PERSON]'s correlation coefficient. In conclusion, we can conclude that the developed model for the evaluation of psychoacoustic quality and its application to measured psychoacoustic parameters can replace the lengthy methods of assessing sound quality through questionnaire surveys. The developed evaluation model through the sound quality index, considering the weights of individual psychoacoustic parameters, can only be applied to a specific product group of household appliances, in this case, washing machines. Based on the steps taken, a proposal was made for the overall process of evaluating the psychoacoustic properties of automatic washing machines based on the developed psychoacoustic model and the proposed validation process. Conceptualization, M.M., M.P. and G.I. ; methodology, M.M., M.P., G.I. and M.B. ; software, G.I. and M.M. ; validation, M.M., M.P. and G.I. ; formal analysis, M.P. and L.S. ; investigation, M.M., M.P. and G.I. ; resources, M.M. and G.I. ; data curation, M.M. and M.P. ; writing--original draft preparation, M.M., M.P., M.B. and G.I. ; writing--review and editing, M.M., M.P., L.S. and G.I. ; visualization, M.P. ; supervision, M.M. and M.B. ; project administration, M.B. ; funding acquisition, M.B. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.