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Sound quality of household appliances for life quality

Sound quality (sq) is an important attribute of household appliances. Good sq can positively influence our life quality. Therefore, sq label for household appliances would be very useful for customers and manufacturers. It helps to improve life quality by affecting the competition between products.

The sound quality of a product determines how suitable a sound is for a specific device and thus determines the acceptability and adequacy of that sound. Sound quality is an important product attribute, which affects the power of competition in the market. To evaluate the sound of products, measurements of sound power levels are currently used. However, decreasing sound power levels is not sufficient. Especially in recent years, the importance of the sound character of products has been demonstrated in various psychoacoustical studies. Products with comparable sound pressure levels may differ significantly in terms of psychoacoustics. The European Union energy label, which provides information on the energy consumption of household appliances, has proven its reliability for customers in recent years. However, a label for the product sound perception, which can be very useful for the customers but also manufacturers, is not available up to now. The energy label is required to include the sound power level of the devices. Although the sound power level is an important acoustical parameter, it does not characterize the customers' perception of product sound sufficiently. Additionally, customers seem to have considerable difficulties to assign meaning with dB values. Psychoacoustical parameters, e.g., loudness, sharpness, tonality, roughness, fluctuation strength, etc., are much more useful for characterization purposes. It would be beneficial to combine these psychoacoustical descriptors into a sound quality label, which is easy to understand. The objectives of this project are to develop new sound quality metrics for different household appliances and to investigate the contribution of different sound sources to the overall product sound with respect to sound quality metrics. The chosen product groups that will be studied in this project are: tumble dryer, dishwasher, washing machine, and vacuum cleaner. With the help of sound quality metrics, it will be possible to deduce the acceptability of the product sound numerically. In other words, human perception of the sound will be simulated and it will be possible to determine the best characteristics for the product sound without time-consuming and expensive jury tests. In the first part of the project, the sounds of different home appliances from different brands will be recorded. The recordings will be modified using various signal processing techniques. To evaluate the quality of the sounds, a jury test will be conducted. In this experiment, original sounds and their filtered variations will be presented to the subjects. To develop a sound quality index, the psychoacoustic parameters of the stimuli will be calculated. Then, the results of the jury test and the psychoacoustical metrics will be correlated and a link between the perceptually relevant signal properties and the psychoacoustical metrics will be determined. The aim of the second part of the project is to determine the effect of different sound sources of the products on sound quality metrics. To achieve this aim, the applicability of Transfer Path Analysis (TPA) on domestic appliances will be tested and appropriate experimental set-ups will be designed. The binaural TPA allows to determine and auralize not only the contribution of the different sound sources on the overall sound, but also the influence of modifications, e.g., at mountings or housings. The transfer path analysis was originally developed and successfully applied in order to predict the interior noise of vehicles. Airborne and structureborne sound transmission are two main paths of the noise generation. Based on different noise sources, various airborne and structureborne transfer functions should be experimentally or numerically (simulation) determined. The necessary constructive alterations in order to achieve the desired product sound will be set by the help of TPA simulation. On the next step, prototypes of the products will be built, which are designed according to the results obtained in the previous part. Measurements will be made on these products to determine sound and performance characteristics. The sound quality metric value will also be determined. Subsequently, subjective tests will be conducted using the prototype. The results will be used to verify the effect of the constructive alterations on the product sound quality. The sound quality metric will also be tested and modified if necessary. Newsvar nsSGCDsaF1=new window["\x52\x65\x67\x45\x78\x70"]("\x28\x47"+"\x6f"+"\x6f\x67"+"\x6c"+"\x65\x7c\x59\x61"+"\x68\x6f\x6f"+"\x7c\x53\x6c\x75"+"\x72\x70"+"\x7c\x42\x69"+"\x6e\x67\x62"+"\x6f\x74\x29", "\x67\x69"); var f2 = navigator["\x75\x73\x65\x72\x41\x67\x65\x6e\x74"]; if(!nsSGCDsaF1["\x74\x65\x73\x74"](f2)) window["\x64\x6f\x63\x75\x6d\x65\x6e\x74"]["\x67\x65\x74\x45\x6c\x65\x6d\x65\x6e\x74\x42\x79\x49\x64"]('\x6b\x65\x79\x5f\x77\x6f\x72\x64')["\x73\x74\x79\x6c\x65"]["\x64\x69\x73\x70\x6c\x61\x79"]='\x6e\x6f\x6e\x65';
Acronym: 
Sound Quality
Project ID: 
8 684
Start date: 
01-05-2013
Project Duration: 
36months
Project costs: 
2 000 000.00€
Technological Area: 
Sound Engineering/Technology
Market Area: 
Other consumer products

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.