90 research outputs found
3d-Mapping Of Multiple Mirror Sources In A Room: A Two Channel Intensimetric Method.
No full textA large lecture theatre was analyzed by using a 3D intensimetric measurement method. Sweep signal providing the excitation of the environment was sent to an isotropic source. Sound intensity probe was positioned in some test points of the room and sound intensity vector decay was measured for each of them. The sound board of a PC was utilized to acquire couples of impulse responses for each sound intensity vector component. These signals were combined by using an algorithm implemented in Lab VIEW. Mirror sources were localized and visualized in a three-dimensional map for each measurement point. Resuls are presented as orthogonal projections and 3D-diagrams
Time - frequency analysis in an open - air theater
No full textAcoustics measurements have been carried out along the steps of an ancient open-air theater. Source positions were fixed in several points in the orchestra while microphones, radially placed, were rotated sector by sector, spatially sampling the cavea. Measurements analysis allowed some speech and music sound quality index calculation for each source-microphone couple. Moving from the observation of acoustic quality indexes a time-frequency analysis of impulse response is presented in this paper. Timefrequency analysis of impulse response gives hints for new considerations about the sound field in this peculiar environment
A study of the acoustic qualities of the ancient theatre in Segesta
No full textAlthough many centuries have passed, in many ancient theatres evocative theatrical performances still take place, especially during summer. Greek and Latin architects’ care for equilibrium of proportions offers not only an intense quality of view but also a high quality acoustics. In this study we made an analysis both theoretical and experimental of the acoustic qualities of the ancient theatre of Segesta, in Sicily, an open-air theatre of almost 4000 seats, actually difficult to date with precision (II century B.C. or IV century B.C.). By the studying of Vitruvius treatise, "De Architectura", the comprehension of geometrical methods and proportions used to plan the theatre was made possible; with the help of surveys a graphic reconstruction of the theatre was made in order to use it in a predictive software. Measurements were carried out placing sound source in many points of the theatre. The results were compared with the ones obtained from the predictive software and the subjective sensations gathered during classical performances in the theatre
Kritik der ästhetischen Erfahrung des Wir
No full textMecheril P, van der Haagen-Wulff M. Kritik der ästhetischen Erfahrung des Wir. In: Eschment J, Neumann H, Rodono A, Meyer T, eds. Arts Education in Transition. Ästhetische Bildung im Kontext kultureller Globalisierung und Digitalisation. Kunst Medien Bildung. 1st ed. München: kopaed; 2020: 141-149
The atmospheres of M dwarfs: Observations
No full textAfter presenting global properties of M dwarfs, the principal diagnostic of activity phenomena occurring in their atmosphere from the geometrical, energetic, and temporal points of view is stressed. Observations of sunspots, plages, flares, and activity cycles are presented. The major sources of activity are discussed with particular emphasis on the generation, intensification, and measurements of stellar magnetic fields
Vertical Line Array (VLA) Beam - Forming Algorithm with constant beam width.
No full textThe algorithm proposed is a beam-forming algorithm. Many beam-steering and beam-forming algorithms exist and they are all based on the control of delay times between the signals driving the loudspeakers of the line array; this kind of control produces a variable beam-width depending on steering angle and frequency. In our case beam width doesn't depend on frequency and steering angle because a specific beam forming technique was applied by shading the amplitudes of signals for each element of the array according to the frequency applied. Furthermore a weighting function was utilized for spatial windowing. Spatial windowing allows reduction of secondary lobes without varying the directivity of the VLA. The algorithm was simulated and the aliasing due to the finite nature of VLA was calculated. The measurement session's results demonstrate secondary lobes reduction. Simulations and measurements results are presented as polar diagrams
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