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Timbre Solfege and auditory profile analysis

Żera Jan

Vibrations in Physical Systems

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2019

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Vol. 30, nr 1

art. no. 2019122

EN

A course in auditory evaluation of sound, called Timbre Solfege, was developed by a team of researchers headed by Professor Andrzej Rakowski, at the Music Acoustics Laboratory, Chopin University of Music. A large part of the course, taught at the Department of Sound Engineering, has been focused on the detection and identification of timbre changes produced by formants and by other kind of sound spectrum modifications. Detecting formants in sound recordings is an auditory task that has much in common with auditory profile analysis, an area of research initiated and developed in psychoacoustics by Professor David M. Green, exploring the fundamentals of detection of changes in the sound spectrum envelope shape, independently of the differences in loudness between the sounds. The purpose of this study is an attempt to relate the results of the Timbre Solfege sound evaluation drills to the theory of the auditory profile analysis.

2

Badania emisji hałasu układu wylotowego silnika spalinowego pojazdu samochodowego

Burdzik R., Konieczny Ł.

Zeszyty Naukowe Akademii Marynarki Wojennej

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2011

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R. 52 nr 1 (184)

7-12

PL

W artykule przedstawiono wyniki wstępnych badań emisji hałasu układu wylotowego silnika spalinowego. Obiektem badań były pojazdy samochodowe. Mierzono poziomy dźwięku w określonych punktach na zewnątrz pojazdu. Do eksperymentów wybrano pojazdy z uszkodzonym układem wylotowym. Pomiary przeprowadzone były w pojazdach w stanie uszkodzonym oraz po wykonanej naprawie. Eksperymenty miały charakter badań wstępnych, dlatego ocena wpływu uszkodzeń na generowany hałas ma wymiar jakościowy.

EN

This article presents the results of research into noise emission produced by a car combustion engine exhaust system. Passenger cars were the object of the research. The sound levels in chosen points outside the car were measured. For the purpose of this experiment cars with damage exhaust system were chosen. Measurements were carried out for damaged cars and after the repair. The research was preliminary therefore the evaluation of the influence of damage on noise emissions was qualitative.

3

Simulations of combustion roar in turbulent attached and lifted turbulent methane jet flames

Marazioti P., Koutmos P.

Engineering Transactions

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2009

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Vol. 57, iss. 3/4

127-144

EN

The present work presents sample results of preliminary computations of the turbulent aerothermodynamic flow field and of the noise generated by the flame front, due to turbulent fluctuations in the flame (combustion roar). in lifted and attached jet diffusion flames of methane. The two-dimensional (2D) time-dependent numerical model was built based on Reynolds-averaged Navier Stokes (N-S) equations. eąuipped with the standard k-e turbulence models to calculate the reacting jet flows. A reactedness inixture fraction two-scalar ex-ponential PDF model, based on non-premixed flame arguments. was combined with a local Damkohler number extinction criterion to delineate between the reacting and non-reacting regions. Althougli the inclusion of the effects of premixed flame propagation could help to improve the model, initial comparisons with experimental results suggest adequate qualitative agreemenl between the computations and reported data. The reasonable agreement obtained for the aerothermodynamic flame characteristics permitted a meaningful computation of the combustion noise (roar) characteristics of the studied flames, in order to address the coupled effects of heat release by the flame and turbulent interactions on the autonomous flame noise generation.

4

Vibroacoustic investigation of a batter head of a snare drum

Skrodzka E. B., Hojan E., Proksza R.

Archives of Acoustics

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2006

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Vol. 31, No. 3

289-297

EN

The modal analysis of a batter head of a snare drum and measurements of the instrument's sound spectrum have been performed. The modal analysis results is comparable to the scarce literature reports. The analysis of the frequency maxima of the sound spectrum revealed significant discrepancies between the modal frequencies and those of the spectral peaks. It has been shown that the lowest mode (0, 1) is the strongest mode of radiation only for central excitation. For non-central excitation, the frequencies of spectral peaks differ significantly from the modal frequencies. It has been found that the batter head was not necessary the most strongly radiating element of the drum system and that the influence of other elements (the snare drum, the shell, the snares) are also very important as far as sound impression is concerned.