Sound preference development and correlation to service incidence rate.

Traditional methods of sound performance measurement for appliances (A-weighted sound power) provide an incomplete picture of the customer’s experience. This is often exemplified by the poor correlation between sound power and customer complaints.
In order to satisfy customer demands for better sounding refrigeration appliances, Sub-Zero needed to gain a better understanding of customer’s perception of sounds generated by the appliance. This was accomplished by conducting a formal Sound Quality jury evaluation and by correlating objective signal processing parameters (Sound Quality metrics) computed over the sounds presented to the jurors to their subjective ranking. The direct result of the study was a sound preference algorithm utilizing several sound quality metrics (rather than simply sound power) that represented the customer’s perception of the sounds. The data generated by the preference algorithm were then correlated with field data to identify performance acceptance thresholds. This rearward looking analysis provided a basis for establishing market-driven product sound preference targets for new product development.