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Psychoacoustic Order Tonality Calculation

SAE International Journal of Advances and Current Practices in Mobility

HEAD acoustics GmbH-Julian Becker, Roland Sottek
  • Journal Article
  • 2019-01-1466
Published 2019-06-05 by SAE International in United States
Quantifying tonalities in technical sounds according to human perception is a task of growing importance. The psychoacoustic tonality method, published in the 15th edition of the ECMA-74 standard, is a new method that is capable of calculating the perceived tonality of a signal. Other methods, such as Prominence Ratio or Tone-to-Noise Ratio do not consider several essential psychoacoustic effects. The psychoacoustic tonality is based on a model of human hearing and thus is able to model human perception better than other methods. The algorithm described in ECMA-74 calculates tonality over time and frequency. In practice, tonalities often originate from rotating components, for example, parts of an electric motor. In these cases, quantification of the tonality of orders is often more interesting than the tonality over frequency. In this paper, an extension of the psychoacoustic tonality according to ECMA-74 is presented. With this extension, it is possible to calculate the order tonalities by using the rotational speed characteristics of the measured signal in order to control the parameters of the auditory filter bank. Two of the…
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Application of a New Perceptually-Accurate Tonality Assessment Method

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

HEAD acoustics GmbH-Roland Sottek
HEAD acoustics Inc-Wade Bray
  • Journal Article
  • 2015-01-2282
Published 2015-06-15 by SAE International in United States
For many years in vehicle and other product noise assessments, tonality measurement procedures such as the Tone-to-Noise Ratio, Prominence Ratio and DIN 45681 Tonality have been available to quantify the audibility of prominent tones. Especially through the recent past as product sound pressure levels have become lower, disagreements between perceptions and measurements have increased across a wide range of product categories including automotive, Information Technology and residential products. One factor is that tonality perceptions are caused by spectrally-elevated noise bands of various widths and slopes as well as by pure tones, and usually escape measure in extant tools. Near-superpositions of discrete tones and elevated narrow noise bands are increasingly found in low-level technical sounds. Existing pure-tone methodologies tend to misrecognize an elevated noise band as general masking lowering the audibility of a tone in the measured vicinity, whereas perceptually they add. To address such issues a new psychoacoustically-based tonality model is presented which evaluates the nonlinear and time-dependent loudness of both tonal and broadband components, separating them via the autocorrelation function (ACF) and giving their…
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Synchronization of Source Signals for Transfer Path Analysis and Synthesis

HEAD acoustics GmbH-Roland Sottek, Bernd Philippen
Published 2014-06-30 by SAE International in United States
In the engine development process, the ability to judge NVH comfort as early as possible is a great benefit. The prediction of engine noise on the basis of a prototype engine without the need to install it in a real car significantly speeds up the development process and leads to a cost reduction, as prototype modifications can be evaluated faster.Meaningful predictions of the perceived NVH comfort cannot be achieved just by comparing order levels, but require listening to an auralization of the engine noise at the driver's position. With the methods of Transfer Path Analysis and Synthesis (TPA/TPS) a prototype engine can be virtually installed in a car using test-bench data. The interior noise can be estimated by combining source signals containing near-field airborne noise radiation and mount forces with transfer functions describing the transmission to the target position in the cabin. Even the transfer functions of a predecessor car could be used if the new car body is not yet available.For several reasons, the source signals for TPA/TPS cannot always be measured simultaneously, in…
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Target Sound Development for Luxury Sedan based on Driving Experience and Preference Study

HEAD acoustics GmbH-Philipp Sellerbeck, Andre Fiebig
Hyundai Motor Company-Seonghyeon Kim, Dong Chul Park, Seokgwan Hong
Published 2013-05-13 by SAE International in United States
The sound sources of modern road vehicle can be classified into three components, driving sound (sound generated through normal driving patterns and events), operating sound (sound generated through actuated components not related to driving), and generated synthetic sound (electronic warning / interactive feedback). The characteristic features of these sounds are dependent upon customer expectation and usage requirements. Additional development complexities are introduced due to each market's cultural and regional differences. These differences in preference must be considered for the establishment of the target sound quality in the early vehicle development process. In this paper, a sound quality goal setting procedure based on user preference is introduced. The sound targets are created as a result of the user preference investigation and validated by intercultural comparison.
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Arrays in Motion - Localization Techniques for Compensation of Relative Motion between Microphone Arrays and Sources

HEAD acoustics GmbH-Sandro Guidati
Published 2013-05-13 by SAE International in United States
With the exact knowledge of the current positions of the microphones in an array and the potential noise sources, it is possible to compensate a relative motion between them. In the past, techniques exploiting this knowledge have been used successfully, e.g., for the measurement of wind turbines and airplane flyover measurement. In this paper, these ideas are applied and modified for the development of a traffic flow observation system.The main purpose of a vehicle pass by measurement is to extract the continuous noise levels of the dominant sources. With the use of advanced video processing or additional sensor information (radar, light barrier) it is possible to create a continuous tracking model of the vehicle. The scan grid in the beam forming algorithm is then recalculated to compensate the movement. In the resulting acoustic video, the vehicle is fixed and the evolution of the sound sources can be observed and auralized for psychoacoustic evaluations.To characterize the acoustic emissions of a vehicle passing by a large number of single measurements under various running conditions have to be…
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An Unusual Way to Improve TPA for Strongly-Coupled Systems

SAE International Journal of Passenger Cars - Mechanical Systems

HEAD acoustics GmbH-Roland Sottek, Bernd Philippen
  • Journal Article
  • 2013-01-1970
Published 2013-05-13 by SAE International in United States
In a vehicle's development process, Transfer Path Analysis (TPA) is commonly used for identifying sound sources and their transmission to a receiver. Forces acting on the structure are the reason for the structure-borne sound share of the vehicle interior noise. In practice it is not possible, or too extensive, to measure operational forces directly. Instead, they are often calculated indirectly from accelerations and from additionally measured inertances. As the car body is a strongly coupled system, a force acting at one position results in accelerations throughout the structure. This crosstalk must be considered by using a dense inertance matrix consisting of the ratios between each force excitation and the accelerations at every sensor position. Then a matrix inversion is performed to solve the system of equations describing the coupling of the structure. For an engine TPA, this method has the disadvantage that it does not include the mounts, although their characteristics can have a major impact on the interior noise.Another widely-used method predicts each body acceleration from the corresponding acceleration at the engine using the…
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Advanced Methods for the Auralization of Vehicle Interior Tire-Road Noise

HEAD acoustics GmbH-Roland Sottek, Bernd Philippen
Published 2012-11-25 by SAE International in United States
Besides powertrain and aerodynamic noise, tire-road noise is an important aspect of the acoustic comfort inside a vehicle. For the subjective evaluation of different tires or vehicles in a benchmark, authentic sound examples are essential. They should be recorded on a real road rather than on a roller dynamometer (avoiding artificial and periodic sounds, especially in the case of a small roller circumference and a smooth surface). The challenge of on-road measurements is the need for separating the components of the interior noise generated by rolling tires, aerodynamic flow and powertrain. This allows for individual judgment of the noise shares.A common approach for eliminating the engine sound is shutting the engine off after acceleration to the desired maximum speed. Operational Transfer Path Analysis (OTPA) can then be used to auralize the tire-road noise at a certain receiver location, where an artificial head records the interior noise during this coast-down. Further signals are needed which are measured with a triaxial accelerometer at each wheel carrier and microphones applied near the tires. Because the aerodynamic flow is…
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Future Acoustics of Electric-Vehicle

HEAD acoustics GmbH-Klaus Genuit
Published 2012-11-25 by SAE International in United States
Since currently a technological shift from automobiles with internal combustion engines now to electric vehicles occurs, new challenges in vehicle acoustics must be met. Although, one of the core duties of NVH engineers will still be the prevention and treatment of disturbing noises, the targeted creation of intended and designed sounds will gain in importance significantly. This sound design task is no longer a choice but a necessity. In the scope of hybrid and electric cars a new kind of acoustic feedback must be created. Surely, the simple electric motor sound, the “tram on wheels”, will not be the final solution accepted by customers. Besides the mandatory use of technical methods like transfer path analysis enabling the reliable identification of the reasons for acoustical problems by separation of sources and transfer paths or binaural panel contribution analysis, investigations of customer preferences on the basis of simulated and real test drives will become more important. All in all, successful NVH and sound design is only done within a chain of precisely fine-tuned working steps and must…
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Tire-Road Noise Analysis of On-Road Measurements under Dynamic Driving Conditions

SAE International Journal of Passenger Cars - Mechanical Systems

HEAD acoustics GmbH-Roland Sottek, Bernd Philippen
  • Journal Article
  • 2012-01-1550
Published 2012-06-13 by SAE International in United States
The powertrain noise of cars has been reduced in the last decades. Therefore in many cases, rolling tires have increasingly become the dominant sources of vehicles' interior noise. For sound design or a reduction of tire-road noise it is important to know the individual noise shares of the tires and their transfer paths. Authentic tire-road noise can only be measured on a real road, not on a roller dynamometer. So far measurements have been performed during a coast-down on the road with the engine switched off, avoiding the influence of engine noise.Operational Transfer Path Analysis (OTPA) can be used to remove the uncorrelated wind noise, and to synthesize structure-borne and airborne tire-road noise based on input signals measured with microphones at the tires and a triaxial accelerometer at each wheel carrier. Simultaneously, the interior noise is recorded by an artificial head.Acceleration, deceleration or other driving maneuvers with the engine running can lead to different tire noises. In this case the conventional method cannot be applied because the engine sound is measured at the source (tires)…
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The Future of NVH Research - A Challenge by New Powertrains

HEAD acoustics GmbH-Klaus Genuit
Published 2010-10-17 by SAE International in United States
Sound quality of vehicles has become very important for car manufacturers. This feature is interpreted as among the most relevant factors regarding perceived product quality. Since the development cycles in the automotive industry are constantly reduced to meet the customers' demands and to react quickly to market needs, ensuring product sound quality is becoming increasingly difficult. Moreover, new drive and fuel concepts, tightened ecological specifications, increase of vehicle classes and increasing diversification, etc., challenge the acoustic engineers trying to create and preserve a pleasant, adequate, harmonious passenger cabin sound. Another aspect concerns the general pressure for reducing emission and fuel consumption, which lead to vehicle weight reductions through material changes also resulting in new noise and vibration conflicts.Furthermore, in the context of alternative powertrains and engine concepts, the new objective is to detect and implement the vehicle sound tailored to suit the auditory expectations and needs of the target group. But, what are appropriate sounds for hybrid or electric vehicles? To answer this question and to allow coping with the growing expectations regarding the acoustical…
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