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Acoustics research centre

Sound quality - making products sound better

A project funded by the Department of Trade and Industry to examine sound quality assessment for UK industries.

In the past, sound design has been about minimising the noise generated by a product. The assumption here is that the lower the noise the better. However, this design principle does not always work. In some cases, it may be impossible to lower the noise level below a certain value given the constraints of cost. Maybe the only way to lower the noise level is to make an ineffective product. In other cases, lowering the level of sound may actually result in customers being less satisfied, even if the product still functions. To take an example, we spoke to a manufacturer of outdoor products who designed a low noise leaf blower. However, when the leaf blower was sold, there were a number of returns from customers who assumed that low noise meant low power. In these kind of cases, there is a need to not only look at the total sound energy emitted, but also to look at the detailed quality of the sound. To take the example of the leaf blowers, maybe the solution would be to design one with a low noise level but one that still sounded powerful.

In this context, the process of sculpting of a sound is sometimes referred to as "sound quality", the term "product sound" is also used in this context. Essentially we are changing the sound of a product to increase customer satisfaction and thereby increase sales. A common example in this context is work by the automobile to optimise the sound of car door closures (this work has been made more widely known by the use of the research in car adverts). Car manufacturers realised that the door closure sound is an important first impression of a car, after all when you enter the show room, one of the first things you will do is open the door, sit in the car and close the door. Consequently, some automobile manufacturers have gone to great lengths to make the sound of the car door closing give the impression of a robust and well designed car.

Sound quality is also sometimes referred to as whether the quality of the sound befits the function of the product. But there is more to sound quality than simply making a kettle sound like a kettle. It is about what you want that product sound to portray: do you want it to give the impression of being powerful, robust, well made etc. Sound quality isn't always just about making the product acceptable (although that is an important part), it can also be about changing the impression of customers in a favourable way. Sound engineering isn't always about avoiding annoyance and bad impressions.

The project has been concerned with providing information and tools for the UK industry to promote the use of sound quality. Sound quality has proven to be a powerful tool in the automobile industry, but then that industry spends considerably more on product development. Nevertheless, sound quality has been used to improve customer satisfaction and sales. In crowded and mature markets, such as domestic appliances, sound quality testing is one way to differentiate a product from that competitors.

To find out more, follow the links:

An Introduction to Sound quality testing

Stakeholder requirements

Assessment methods: jury testing and objective methods

Knowledge transfer

Brief Bibliography


For more information about Sound Quality please email Trevor Cox at t.j.cox@salford.ac.uk.