Product sound quality - from perception to design

Sound as a Marketing Opportunity

If product sound has both good and undesirable features, are there ways to favorably present a product with regard to its sound? There are many examples of companies doing just that. A Harley-Davidson catalog contained a recording of its sound (Figure 2, Sound J).1 The company applied to have the sound trademarked, like the 3 chimes of the NBC network. Although their application has been dropped, they maintain and many agree that the sound identifies their product.

Lexus automobiles are known for the excellence of their interior quietness (Figure 3) and both their television and print advertising associate that quietness with sophistication (symphony orchestras) and advanced technology (wind tunnels).

In the area of products for the home, examples include television advertising by Hunter (overhead fans) that associates the quietness of their fans with the comfort and security of the home. Television and print advertising for Whirlpool dishwashers claim that their dishwashers do not interfere with conversations around the breakfast table or when using the telephone (Figure 4).

Manufacturers can learn whether or not product sound is an issue for their products in a variety of ways. Focus group sessions can be designed to determine the importance of sound as a feature (Table 1), and service representatives, dealers and customer letters and calls are all sources for information about the importance of sound to the customer. If the company decides that sound is an issue, then jury testing is carried out to determine what the goals for product sound should be, and how they can be achieved through choices of materials and components.

Acoustical Sensory Profiles and Jury Testing

Customers make judgements about product sound in terms of its loudness, annoyance, amenity and what it says about the product. In other words, customers make their judgements based on a product's Sound Quality. Product Planning tries to take information about those judgements and specify to designers what needs to be accomplished regarding the sound, as we saw for the door closure sound. The product team therefore has to make the transformation between the judgements of users and the engineering choices for structure, gearing, motors, fans, electrical components, etc., that make up the product. The process needs a mapping between the two (Figure 5).

There is no question that we can faithfully record the sound of the product, but we do not know the algorithm or metric to convert that signal to an "acceptability rating." The taste and flavor industries have a similar problem; they don't know what to measure. Those industries have used panels of trained experts to establish "Sensory Profiles" for their products (Figures 6-7). Products are rated according to descriptive words (a lexicon), and the product that best matches the favored profile is deemed the best.

My company has carried out research on SQ design sponsored by our National Science Foundation in its Program for System Dynamics and Controls. A goal of that effort has been to develop the mapping just discussed using Acoustical Sensory Profiles (ASPs). We believe that we have arrived at metrics that are helpful in predicting consumer responses, using as the intermediary an Acoustical Sensory Profile for a particular product type. Our initial research has involved developing ASPs for the sounds of vacuum cleaners and washing machines.