Open Access
Zwicker's annoyance model implementation in a WASN node
(Sociedad Española de Acústica, 2019) Pastor Aparicio, Adolfo; López Ballester, Jesús; Segura García, Jaume; Felici Castell, Santiago; Arana Burgui, Miguel; Ciencias; Zientziak
Wireless Acoustic Sensor Network (WASN) nodes for noise measurement and acoustic environment description is a common use in the environmental measurement within the Smart City. The implementation of the psycho-acoustic parameters in each WASN node is a tricky problem and currently is the battle horse in the automatic acoustic environment description. In this work, the implementation and the improvement of the algorithms used for each psycho-acoustic parameter is described and the performance of the implementation measured.
Open Access
Influence of recording technology on the determination of binaural psychoacoustic indicators in soundscape investigations
(Institute of Noise Control Engineering, 2019) San Martín Murugarren, Ricardo; Arana Burgui, Miguel; Ezcurra Guisasola, María Amaya; Valencia Leoz, Ana; Ciencias; Zientziak
The evaluation of soundscapes is mainly carried out through field surveys, using soundwalking methodologies. Through rating scales and annotation of comments, the experiences and expectations of the participants are collected. Acoustic and psychoacoustic indicators are also reported to achieve a complete description of the acoustic environment. Binaural measurement systems should be used for registration in order to consider the way in which humans perceive the acoustic environment. Artificial heads or in-ear binaural microphones are the usual devices for this purpose. Further recording technology such as sound field microphones or microphone arrays are also used in soundscape investigations. These methods can provide a higher level of immersion in a later reproduction of the recorded soundscape through multi-channel setups. However, in contrast to direct binaural recordings, the determination of binaural psychoacoustic indicators requires to perform binaural synthesis by means of Head-Related Transfer Functions and signal processing. In this communication, the influence of different recording devices on obtaining psychoacoustic indicators such as binaural loudness and sharpness is analysed.
Open Access
Characterization of combustion anomalies in a hydrogen-fueled 1.4 L commercial spark-ignition engine by means of in-cylinder pressure, block-engine vibration, and acoustic measurements
(Elsevier, 2018) Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Sáinz Casas, David; Machín Mindán, Jorge; Arana Burgui, Miguel; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2
Abnormal combustion phenomena are among the main hurdles for the introduction of hydrogen in the transportation sector through the use of internal combustion engines (ICEs). For that reason the challenge is to guarantee operation free from combustion anomalies at conditions close to the ones giving the best engine output (maximum brake torque and power). To this end, an early and accurate detection of abnormal combustion events is decisive in order to allow the electronic control unit deciding suitable correcting actions. In this work, an automotive size 4-cylinder 1.4 L naturally aspirated port-fuel injection spark ignition Volkswagen engine adapted to run on hydrogen has been investigated. Three distinct methods (in-cylinder pressure, block-engine vibration and acoustic measurements) have been employed to detect abnormal combustion phenomena provoked through the enrichment of the hydrogen-air mixture fed to the cylinders under a wide range of engine speeds (1000–5000 rpm). It has been found that the high-frequency components of the in-cylinder pressure and block engine acceleration signals obtained after a Fourier transform analysis can be used for very sensitive detection of knocking combustion cycles. In the case of the ambient noise measurements, a spectral analysis in terms of third octave bands of the signal recorded by a microphone allowed an accurate characterization. Combustion anomalies could be detected through more intense octave bands at frequencies between 250 Hz and 4 kHz in the case of backfire and between 8 kHz and 20 kHz for knock. Computational fluid dynamics simulations performed indicated that some characteristics of the engine used such as the cylinder valves dimensions and the hydrogen flow rate delivered by the injectors play important roles conditioning the likelihood of suffering backfire events.
Open Access
Strategic noise map of a major road carried out with two environmental prediction software packages
(Springer Netherlands, 2010) Arana Burgui, Miguel; San Martín Murugarren, Ricardo; San Martín Erviti, María Luisa; Aramendía Santamaría, Emilio; Física; Fisika
The main objective of this study is to analyze the differences found in the results of noise mapping using two of the most popular software techniques for the prediction of environmental noise. The location selected to conduct the comparative study is an area encompassed by the ring road that surrounds the city of Pamplona and on a grid, with a total of 6 × 105 points, approximately. In fact, and as the Environmental Noise Directive points out, it is a major road designated by a Member State (Spain). Configuration of the calculation parameters (discretization of the sources, ground absorption, reflection order, etc.) was as equivalent as possible as far as programs allow. In spite of that, a great number of differences appear in the findings. Although in 95.5% of the points the difference in the noise level calculated from the two programs was less than 3 dB, this general statistic result concealed some great differences. These are due to the various algorithms that programs implement to evaluate noise levels. Most differences pertain to highly screened receivers or remote ones. In the former, the algorithm of visibility is the main cause of such differences. In the latter, differences are mainly brought about by a different implementation of the propagation under homogeneous and favorable atmospheric conditions from both software systems.
Open Access
Measurement and analysis of mechanical noise in wind turbines
(Institute of Acoustics, 2016) Arana Burgui, Miguel; Machín Mindán, Jorge; San Martín Murugarren, Ricardo; Ciencias; Zientziak
Open Access
People exposed to traffic noise in european agglomerations from noise maps: a critical review
(De Gruyter, 2014) Arana Burgui, Miguel; San Martín Murugarren, Ricardo; Salinas Hilburg, Juan Carlos; Física; Fisika
Two of the main objectives of the European Directive on environmental noise are, firstly, to unify acoustic indices for assessing environmental noise and, secondly, to standardize assessment methodologies. The ultimate goal is to objectively and comparably manage the impact and evolution of environmental noise caused both by urban agglomerations and by traffic infrastructures (roads, rails and airports). The use of common indices and methodologies (together with five-year plan assessment required by the authorities in charge) should show how noise pollution levels are evolving plus the effectiveness of corrective measures implemented in the action plans. In this paper, available results from numerous European agglomerations (with particular emphasis on Spanish agglomerations) are compared and analysed. The impact and its evolution are based on the percentage of people exposed to noise. More specifically, it demonstrates the impact caused by road traffic, which proves to be the main noise source in all agglomerations. In many cases, the results are extremely remarkable. In some case, the results are illogical. For such cases, it can be concluded that either assessment methodologies have been significantly amended or the input variables to the calculation programs have been remarkably changed. The uncertainty associated with the results is such that, in our opinion, no conclusions can be drawn concerning the effectiveness of remedial measures designed within the action plans after the Directive’s first implementation Phase.
Open Access
An efficient algorithm for the evaluation of tonality and the determination of the tonal frequency according to IEC 61400-11
(Institute of Noise Control Engineering, 2019) Arana Burgui, Miguel; San Martín Murugarren, Ricardo; Ezcurra Guisasola, María Amaya; Valencia Leoz, Ana; Llorente, Elena; Ciencias; Zientziak
The terms of tonality and tonal audibility of the noise emitted by wind turbines are defined and described in the standard IEC 61400-11. The procedure for tonality assessment at different wind speeds based on the narrowband analysis is explained in section 9.5 of the standard. After sorting spectra into wind speed bins, the overall tonal audibility is determined if at least six of ten of the narrowband spectra have an identified tone with the same origin. The standard describes a procedure for tonality assessment by means of a flowchart. Tones of the same origin are treated and reported as one tone. However, the standard does not specify the final value of the frequency of the tone. An efficient algorithm has been developed to evaluate the tonality of the noise emitted by wind turbines. Likewise, different alternatives to specify the final frequency of the tone are discussed, based either on their frequency of appearance in the total of the number of measurements or on the tone levels produced by such frequency.
Open Access
Are urban noise pollution levels decreasing?
(Acoustical Society of America, 2010) Arana Burgui, Miguel; Física; Fisika
The majority of acoustic impact studies developed over the last 50 years have used a similar acoustic parameter Leq, Ldn but the noise mapping methodology has been very uneven. The selection of the measurement points, the measurement periods, or the evaluation indices have not followed a unique criterion. Therefore, it is not possible to compare the sound pollution levels between different cities from those studies, at least in a rigorous sense. Even more, different studies carried out in the same city by different researchers during different years and using different methodologies are not conclusive whether the acoustic pollution increases or decreases. The present paper shows results, with statistical significance, about the evolution of the acoustic pollution obtained for two Spanish cities, Pamplona and Madrid. In both cases, it can be concluded that noise pollution decreases over time (P<0.01).