Assessing the subjective response of consumer product acoustic stimuli in the presence of background variables

•Background variables in a listening study can have a statistically significant impact on subjective response.•A systematic experimental approach can provide insights of the effects of background variables in a listening study.•Consumer product sound differences greater than 2 to 4dBA show strong evidence of a perceivable change in level.•Focus groups and attribute screenings can provide a holistic view on the psychological implications of product sound. Sound quality studies linking subjective response of consumers to objective psychoacoustic metrics are commonplace in product engineering. A typical consumer product sound quality study attempts to formulate an equation to predict consumer response without the presence of background variables. Common treatment of background variables includes controlled listening environments and blind studies. While these studies provide insights into psychoacoustic perception of consumer products, they lack the ability to predict a product’s reception during real-world service. The intent of this study is to quantify the effects of introducing background variables as experimental factors, while developing guidelines of acoustic quantity target setting of home appliances. The background variables in this study were treated according to a factorial design of experiments across eight groups of test subjects. The results showed that indicating the appliance brand to the test participant can have a statistically significant impact on the perception of sound quality of an appliance during normal operation. In addition, a linear relationship of sound level versus subjective response was developed to provide further insights to perceivable changes in sound level in the presence of typical background variables experienced in the home and marketplace. To further link the subjective response to the Voice of the Consumer (VOC), a focus group study with applied laddering theory was conducted to relate test subjects’ sentiment to their underlying values.