Retail Observer

MAY 2022 RETAILOBSERVER.COM 31 like "Quiet Wash," "Silent Wash" and "Ultra-Quiet Wash." However, the consumer had no way to compare the various packages and had to hope that the name of the sound package identified how quiet the product actually was. Sales staff at retailers were also unsure of how one unit compared to another, and through the 1990s, the sound levels of most dishwashers changed little. In the early 2000s, a major appliance retailer approached Owens Corning to help develop a standard to provide a sound rating for dishwashers that would provide data for customers to use to compare products. The sound rating standard for the dishwasher is based on the measurement of the average sound power level emitted by the dishwasher during the full wash cycle. The dry cycle would be included if an active drying system was present 2 . 3. LABELING SOUND POWER VS. SOUND QUALITY Sound power is the acoustic energy radiated by the dishwasher during operation, as opposed to sound pressure which is what is sensed by the ear. The advantage of sound power is that it is not influenced by the design of the space where the dishwasher is installed. The final version of the standard incorporates internationally accepted sound power determination standards and North American operational practices. For the dishwasher, this type of measurement works well because the characteristics of the sound, frequency content (think "Pitch" in musical terms) and the amplitude (think "Volume" in musical terms) are nearly equal at most frequencies and stimulate our ears much in the same way as "white noise." White noise, similar to white light, is sound that produces equal energy at all frequencies. The sound measurement is made in decibels. Decibels are a logarithmic scale that compresses the amazing range that the human ear can sense, where the loudest sound sensed by the ear is approximately a hundred billion times higher than the quietest. Microphones and analyzers can measure sound levels and provide a filter representing how a human would sense the sound, named Type A weighting. For a dishwasher, the sound level is similar across most of the measurement frequency range. The Type A weighting measure does well to represent how a person would perceive this type of sound. When the sound contains tones, buzzes, clicks or hums, the perception of the listener changes based on the frequencies of the sound. For example, a motorcycle with a smaller or higher revving engine will be perceived to "whine," whereas one with four large cylinders will be perceived to "rumble." Objectively, the sound levels may be the same, but subjectively, people may prefer the "rumble" more than the "whine." The rating of these subjective perceptions is called Sound Quality, which can be applied to more complex sounds. This is the measure used extensively in the automotive industry to develop luxury vehicles. Clothes washers, where the sound shifts between the agitation and the spin with intermittent water fill and drain sounds, would be good candidates for this type of measurement for a rating system. 4. SOUND LABELS INFLUENCE CONSUMERS Having the right standard for the dishwasher allowed quick acceptance in the market. Consumers took advantage of this new tool to buy dishwashers with lower sound ratings. Soon, all manufacturers were utilizing the Owens Corning Acoustic Research Center to provide sound ratings for their dishwashers and advertising the low sound levels, as one example shows in Figure 2. By the 2010s, brand segmentation for dishwashers matured and three separate branding levels emerged (See Figure 3). Manufacturers had quickly identified that the premium units provided greater profit and

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