Acoustics research centre
Customer feedback, standards and labelling
Manufacturers of appliances were asked to express opinions of their customers knowledge of sound quality.
58% of the companies thought that their customers know what they want from their products, while 42% thought they don’t. When asked about how customers would like their product to sound ideally, 83% said the customer would like their products to sound as quiet as possible. But 17% of the manufacturers acknowledged that quietness is not always that good, because the sound of the product is a source of information and part of the identity of the product. Furthermore when a product such as a hedge trimmer is quiet, it can become a dangerous tool. One manufacturer gave an example of a quiet vacuum cleaner for outdoor use. The vacuum was found not to be successful with the customers because they thought it was not working. They therefore preferred a product with a good sound rather than a quiet sound.
The manufacturers were also asked if they considered ageing and/or disabled populations when doing sound quality assessment. All disregard them with the exception of one manufacturer, who considers the possible interferences between the sound of their product and hearing aids. Such consideration was given because of the personal experience of the designer. Overall there is very limited consideration of the ageing population and people with audio or visual impairments.
None of the companies interviewed were required to comply with consumer sound labelling and regulations (except the regulations for outdoor products) manufacturers. However 60% had their own internal standards. In general the manufacturer’s opinion on sound labelling is relatively poor. They are fully aware of the energy label, however none mentioned:
- 'Blue Angel' labelling in Germany: German Institute of Quality Assurance and labelling (RAL), (Deutsches Institut für Gütesicherung und Kennzeichnung)
- Federal Environment Agency, Germany
- The 'Ecolabel' European label, Regulation (EC) No 1980/2000
- Sound labelling for computers used in Sweden
Manufacturers of outdoor products have strongly expressed that the dB is poorly understood by consumers. The manufacturers therefore are in favour of a change from sound power label in dB(A) to a sound quality label.
Appliance manufacturers consider sound when identifying an annoying sound, but most of them do not look at the sound quality of their product, in a similar way to a car manufacturer. This means they are not after a sound that is, for example, sportive, robust or sharp. Measurements are already considered to be adequate; however, design teams often do not include an acoustics expert. This would explain why so few companies consider using FFT analysers. They also are unaware of the existence of software for sound quality. There appears to be a big gap between current practice in the UK and state-of-the-art sound quality assessment. However, state-of-the-art practices are relatively expensive. Attitudes towards sound quality assessment would also change if the product sound could be heard before purchase in the retail shop (as in the automobile/audio industry) or on internet.
Some companies would like to know how to use an FFT analyser to understand the noise of their product better and have access to rooms with defined acoustics. Others suggested access to some software for sound quality. With the exception of two companies, manufacturers seem to be unaware of psychoacoustics indices, but all agree that although sound quality is not directly measurable it can be described by adjectives and by answering carefully worded questions.
Consumers Associations and Sound Quality
The Consumers Association usually looks at criteria relevant to consumers which relate to the performance of the product, ease of use, some key features and convenience. Sound quality is mainly considered for sound reproduction products because the sound is fundamental. When asked about sound quality of domestic appliances, they require them to be as quiet as possible with no annoying sound.
Associations representing people with hearing impairments consider the sound quality of some products without calling it ‘sound quality’. For example, they will create products which could be heard by people with hearing impairments such as alarm systems, ring tones on the phone or car indicators. Other products on the market can be modified in order to function better for deaf or hard of hearing (H-of-H) people, but this could involve a visual rather than aural modification. In the future, they would like to see products useable by everyone in society. In the case of the visual and hearing impaired, the product ergonomic is mainly considered rather than the sound quality. Some specific projects between the association and the manufacturer do take place where sound modifications can be done, but this is the exception rather than the rule.