FEATURES OF EXPERT STUDIES OF AUDIO EQUIPMENT (Valentina Zakharchuk)

Valentina Zakharchuk,
PhD of Technical Sciences, Associate Professor, Department of Expertise of Goods and Services
Odessa National Economic University, Ukraine, Odessa
ORCID ID: https://orcid.org/0000-0003-4739-3828

With the constant development of mobile technology and electronics, the audio market is constantly changing and adapting to changes in consumer demand. In recent years, there has been a shift in priorities from large stationary devices to compact and portable ones that are significantly more convenient to use and offer greater versatility and practicality.
With the development of the audio equipment market, it is necessary to study and systematize information about the range of factors of consumer properties, the assessment and examination of audio equipment which determines the relevance of the research topic.
The natural result of the objective conditions of the economic life of our state is a dynamically growing demand for the application of commodity knowledge and an increase in the number of studies in this area.
New standards of social life, the active entry of the country into the world market, the formation of a new level of needs in this regard, the involvement of new groups of goods in the daily circulation, the awareness of the consumer of his rights to satisfy specific needs, the actual abolition of outdated laws governing economic relations – all this constantly requires the formation of a new approach to expert research.
Taking into account the foregoing, it can be concluded that the commodity examination as one of the branches of commodity knowledge experiences the influence of these factors and, under the influence, renews and changes its content.
The expertise of audio equipment is an industry that requires more attention from scientists, researchers and experts, because, along with other products of the non-food group, it occupies a significant place in everyday life and has many unresolved problems.
The examination of the quality of audio equipment is carried out in accordance with the requirements of the technical conditions of the contract and regulatory documents establishing the corresponding requirements. The examination of audio equipment can be carried out by the organoleptic method, by conducting an expert assessment (expert listening). In this case, a scoring system is introduced, and detailed explanations are provided regarding the objective assignment of a certain grade.
The examination of audio equipment is carried out in several stages:
- the marking of products is studied in detail for compliance with the requirements of the regulatory documents of Ukraine;
- the analysis of the visual impact, configuration of audio technical products is carried out;
- an expert study of the sound of audio technical products is carried out in order to identify the presence or absence of deficiencies in sound reproduction.
When developing an expert method for assessing audio equipment, the method of expert assessments was chosen as the main one, which allows you to accurately assess the sound quality of audio technical goods.
The method of expert assessments is a scientific method that allows you to obtain an objective assessment based on a certain set of individual opinions of experts.
The method of expert assessments is actually a forecasting method, the fundamental criterion of which is the achievement of the agreement of all members of the expert group. Experts familiar in interrelated fields of activity answer in detail the questions of the questionnaire related to the problem under study. Each of them records their opinion on the problem, and then reports the answer to their colleagues. In case of a discrepancy between his forecast and the opinion of others, the expert is obliged to explain the reason for such a discrepancy. Then the procedure is repeated until the opinions of the experts coincide. At the same time, it is necessary to maintain anonymity, which helps to avoid the possibility of group reflections on a problem situation [1, 2].
In the process of developing the expert method of audio technology, an individual interview method was chosen, which was modernized for the most effective use in the case of an individual expert study.
The algorithm of the expert method of audio technology includes the following stages:
- preliminary acquaintance with the objects of research, their characteristics, features, etc.;
- creating as identical listening conditions as possible, in which all objects of audio equipment will be in equal conditions;
- conducting expert listening to specially selected musical materials;
- the wording and written documentation of the expert opinion on the sound quality of the assessed samples of audio equipment.
To carry out the expert method of audio equipment, 10 defining consumer properties of audio equipment were proposed, a brief description is given in table. 1.
Table 1 – Determining consumer properties of audio equipment

Audio technical products are complex engineering and technical structures, consisting of a large number of elements. Defects in audio equipment are divided into internal and external.
Internal ones include defects in printed circuit boards (non-soldering of elements, violation of the integrity of conductive tracks, damage to the capacitance of capacitors, etc.), defects in electric motors and mechanical parts (failure / incorrect operation of an electric motor, rupture of drive belts, deformation of drive rollers, etc.) , defects in power supply (defects in built-in transformers), defects in the battery (violation of the temperature regime, loss of capacity and resource, failure, etc.), defects in the software part (malfunction of the system, freezing, errors in reading files, etc.) ) and internal assembly defects.
External defects include defects in audio equipment cases. Such defects are considered scratches, stains, non-staining, color / shade mismatch, uneven gaps, cracks, dents and other defects formed during the production, transportation or storage of products.
According to the degree of influence on quality, defects are rated as critical, significant and insignificant. Defects are considered critical, the presence of which does not allow the device to be used for its intended purpose. For example, for a digital-to-analog converter, a critical defect would be damage to the digital-to-analog conversion microcircuits, for a CD player, a failure of the transport laser, and the like.
Significant defects are those that significantly affect the level of functionality and durability of audio equipment, and significantly worsen the appearance.
Minor defects only affect the appearance. They come to light when inspecting products, but subtle when listening. If in the standards such defects are not named among the permissible ones, then they must be eliminated.
The main reasons for the occurrence of defects are as follows: low-tech design, poor quality of materials, unsatisfactory operation of equipment, violations of the technological and organizational regime, packaging, transportation and storage rules. The low-tech design is manifested in the insufficient perfection of the circuit design of audio technical products.
The presence of defects in materials and parts is explained by insufficient control, the presence of hidden defects. Violation of technology can manifest itself in non-performance of the intended operations, violation of standards and performance modes.
In an expert study of audio equipment that was in operation, signs of use are allowed, namely:
- for digital-to-analog converters, CD players, portable players and any other audio technical product that has mechanical buttons, slight abrasions are allowed on elements that are often touched by the consumer;
- for turntables and compact discs, it is normal to wear out the mechanically moving parts of the device (electric motors, trays, rollers, etc.). For turntables, natural wear of the pickup stylus is also allowed;
- for all audio equipment, minor scratches, fingerprints, dust particles and abrasions on the support legs of the products are acceptable.
Deterioration of the main sound characteristics (change in the amplitude-frequency characteristic, decrease in the signal-to-noise ratio, increase in the number of nonlinear distortions, etc.) in any case, including after long-term operation, is not allowed.
The prospects for further research in this area are the formation of the basis of expert research on audio technology. The results of research on audio equipment will play the role of a concrete basis for the development of a modern methodology for the examination of audio equipment using the expert method.

1. Methodology of commodity examinations of non-food products: a monograph / V.E. Sytsko [et al.]; under common ed. Dr. Tech. Sciences, Professor V. E. Sytsko. – Gomel: UO «BTEU PC», 2017. – 228 p.
2. Kolomiets T. M., Prytulska N. V., Romanenko O. L. Examination of goods: a textbook. Kyiv: Nat. trade and economy Univ., 2001. 274 p.
3. Tutorial: Digital to Analog Conversion – The R-2R DAC // [Electronic resource]. – Access mode: https://www.tek.com/.
4. Encyclopedia of sound. [Electronic resource]. – Access mode: http://aovox.com/.