In recent years, the product design has explored the characteristics of sounds produced by a product, especially the electronic sounds implemented in interface design of a product, and their influence on the users’ feeling, in order to improve the quality of product image.
This research analyzed the physical and psychological characteristics of hitting sounds produced by hammers or other metal hand tools, and investigated the felt images of theses sounds through survey. First, to include the range of studied sound samples as broad as possible, we collected and recorded varied hitting sounds generated by hammers as well as by other metal products. The sound samples were recorded by high sensitive instruments in the real working environment. There were 140 sound samples recorded and analyzed on their physical composition (such as frequency spectrum, etc.) by specialized recording software. Some samples were adjusted to change some attributes in order to make them varied enough to distinguish from other samples.
Experts’ then were invited to screen 80 sound samples out of the pool of 140 sound samples according to the discernible power of the samples. The number of sound samples was further reduced to 40, through analyzing the data in the pilot test, for formal experiment.
On the other hand, we collected the sound adjectives often used in relevant researches. Subjects were asked to group these adjectives according to the similarity in meaning. Cluster analysis was conducted on the classified data to conclude some identical groups which include adjectives describing psychological feeling and physical feature of the sounds. Thirty sound adjectives were selected from each group of adjectives and were verified for their suitability through the pilot test. At last, 10 adjectives were decided to be used as scales in the formal sound image evaluation test through the factor analysis in the pilot test.
Thirty subjects were recruited to evaluate the 40 sound samples on the 10 scales of sound adjectives. The evaluation was rated on 7 levels form 'not feel strong' to 'feel strong' on each adjective. The sound stimuli were presented to subjects by specialized recording apparatus in a sound isolated laboratory during the experiment session which was arranged in the time after dusk to reduce the noise of the environment.
The averaged scores over 30 subjects of the evaluation of each sound sample on each adjective were regarded as dependent variables; whereas the physical compositions of sound samples were treated as independent variables. Accordingly, for each adjective, the corresponding linear regression analysis was conducted to conclude the influence of sound features on each perceived image. This result is expected to assist product designers to design appropriate product sounds with desired images.