A Detailed Study to Evaluate Sporty Sound Character of Passenger Cars

Sound design is becoming increasingly important for vehicle manufacturers. ‘Sportiness’ of a car is one of the important criteria to consider while designing a car for passionate customers and those who love aggressive driving. Automobile manufacturers are identifying a typical sound for their cars as a ‘key product specification’ to attract particular market. This study focused on identifying frequency ranges and order content through a detailed study of subjective feelings based on physiological acoustics. A benchmark study of various different sport vehicles has been done to measure and record sound samples; these samples were further analysed based on sound quality parameters. Subjective evaluations were carried out by NVH experts to determine their concept of sportiness. Frequency ranges and order noise quantity were confirmed by correlations between subjective and objective evaluations under various customer drive patterns. Relations of the dominant exhaust firing order and its harmonics with sporty sound quality were determined. In addition, the curve distribution zones of the corresponding order noise were formed, and the order quantitative target of the sporty sound quality was considered. Finally, different passenger vehicles with sporty and quiet qualities were validated for above results. CAE analysis using GT-Suite software is done to simulate a few concepts of exhaust systems to get results in line with our defined targeted zone. A novel test rig and test methodology for insertion loss measurement is developed for rig-level validation of mufflers. This facility was further enhanced to add reciprocating order noise content and reduce vehicle-level iterations. The best concept was tested on a targeted vehicle to validate its sportiness through objective and subjective assessment. The results obtained showed a very good correlation and proved that the defined order noise target zone of the sporty sound quality is accurate and very effective in achieving the desired sport sound character.