Acoustics research centre
The written questionnaire summary
The replies to each question received from all of the manufacturers is summarised below.
Is the loudness or quietness of your products important to customer satisfaction? And do you think that the sound quality of your products is important to customer satisfaction?
Respondents were asked to 'tick one box'. When asked is the loudness or quietness of your products important to customer satisfaction 50% of respondents answered 'always' and a further 37% answered 'often'. In reply to the question 'Do you think that the sound quality of your products is important to customer satisfaction?' 46% also answered 'always' and a further 24% answered 'often'. Only one manufacturer returned the answer 'never' in response to the question on sound quality.
This lends support to the idea that a significant proportion of manufacturing companies rate sound quality as an important factor when investigating the acoustic emissions of products. Interestingly one manufacturer said they considered sound quality as 'always' important to customer satisfaction whereas loudness was only 'sometimes' important.
When do you typically consider the loudness of a product, in the design cycle? and when do you typically consider the sound quality of a product, in the design cycle?
These questions were designed to reveal when loudness and sound quality were considered in the design cycle of a product, and respondents were asked to tick 'as many boxes as apply'. From the replies 59% of the respondents said they considered sound quality at the 'early stages of design' (76% of respondents considered loudness at this stage), 48% 'once a prototype is produced' (54% said they considered loudness at this stage) and 37% at the 'end of product development' (more than the percentage that said they considered loudness at this stage which was 33%). Only three companies selected the options 'sound quality never considered' and one manufacturer selected 'sound quality not important'. None of the companies ticked the boxes 'loudness not important' or 'loudness is never considered'.
The majority of the respondents answers fitted into three categories. Those that considered sound quality: at the early stages of design (28%); once a prototype is produced (15%) or at all three stages of the design cycle (22%). Companies that returned the reply 'other' for consideration of sound quality were further investigated by including them in the list of manufacturers selected for telephone interview (see below).
If you carry out sound quality assessment, how is this done?
The three answers to this question are shown in the diagram below along with the 'other' option; once again respondents were asked to tick 'as many boxes as apply'. Three companies had answered sound quality is 'never considered' to the previous question and therefore didn't reply to this question. The two most popular methods of sound quality assessment were found to be 'informal listening by the designers' (63%) and 'accessing acoustic signals on instrumentation' (72%).
48 % of respondents only used one method of sound quality testing. The two major categories being 17% of respondents who said that they used 'informal listening by the designers' alone (although two of these had also ticked the 'other' box), and 28% who said that they relied on 'accessing acoustic signals on instrumentation' alone (although one of these companies had also ticked the 'other' box).
46% relied on more than one type of testing for sound quality in two major groups: 28% said they used a combination of informal listening by designers and accessing acoustic signals on instrumentation and 15% said they used a combination of all three options.
What effect did manufacturer size have on the test methods used?
Formal tests using independent juries was not used by any companies with less than 100 employees. Whereas 21% (five of the twenty four) companies with 100 to 1000 employees and 36% (four of the eleven) companies with more than 1000 employees used formal testing with independent juries.
The five companies that had selected the 'other' option for sound quality assessment were further investigated by including them in the list of manufacturers selected for telephone interview (see below).
Following up the written questionnaire
The written questionnaire was followed up with telephone interviews of a selection of the companies. The time consuming nature of the telephone interview process placed limitations on the number of companies selected for telephone interview. Therefore this stage was not intended to give a representative cross-section of the role of sound quality throughout the whole of the UK's manufacturing industries. Instead the companies interviewed were chosen in order to investigate areas in which manufacturers appeared to demonstrate an enthusiasm about sound quality and its potential applications despite it not already being an established requirement of the product, or to investigate areas in which little sound quality research has been documented. Companies were also chosen to investigate opinions on sound quality in SMEs. The nature of the semi-structured interview strategy allowed this smaller sample to be examined in more depth.