Simulative investigation of required spatial source resolution in directional room impulse response measurements

International audienceIn classical and standardized room acoustic measurements, the directivity of sources and receivers is either not considered, specified to be omnidirectional for inter-measurement comparability, or for the receiver defined as HRTF or spatial audio formats. These room impulse response (RIR) measurements allow for the analysis of certain aspects of an acoustic scene. Parameters such as Early Decay Time (EDT) attempt to reflect the listening impression, while others such as the reverberation time serve as physical descriptors and for the evaluation of rooms for different purposes. The explicit non-consideration of the source and receiver directivity waives an abundance of information, which is essential for a complete description of the spatial composition of an acoustic scene, for example in an auralization. On the one hand, a more complete description raises the degree of realism in auralizations, presumably intensifying the immersion of human listeners. On the other hand, the freedom of arbitrary source-receiver directivity combinations opens up the possibility of directional acoustical analysis like scanning single reflection paths within a room.For the measurement of directional room impulse responses (DRIR) several measurement methods and instruments have been implemented in the past. Most of them aim either at fast measurements or at measurements of a high spatial resolution. The compromise of obtaining a sufficiently high resolution in an acceptable time usually is often disregarded due to the ambiguous definition of a sufficiently high resolution.Before the development of suitable methods and instruments, the importance of directivity in an acoustical scene has to be determined. This entails the question if and up to which complexity the measurement of directional room impulse responses offers an advantage for room representations in auralizations and for parametric room acoustic descriptions.A sufficiently high resolution can be defined in many ways, either in regard to just noticeable differences for human listeners, or objectively regarding the effects on technical parameters. This work investigates the effect of the source directivity resolution on room acoustical parameters. Since real measurements contain too many uncontrollable influences such as time variances and sources that can radiate the required directivity with a sufficient precision do not yet exist, this investigation is done using room acoustic simulations.First, the modelling of suitable artificial directivity will be explained. The spatial resolution will be denoted by the corresponding spherical harmonic order. The goal is a directivity with a minimum beam width for each given spherical harmonic order without strong side lobes. This characteristic represents the worst case for each resolution. The generated source directivity will then be used in hybrid ray tracing and image source room acoustic simulations in three rooms of different size and acoustic property. This approach allows a more generally valid statement about the impact of the source directivity.The results will be discussed using the impact on objective room acoustic parameters as an indicator for the required spatial source resolution. Subjective parameters will be considered as an outlook towards the impact on the human perception. The findings are meant to aid the design of measurement instruments for directional room impulse response measurement in reasonable measurement times with a sufficiently high spatial resolution

ЭЛЕКТРОННЫЕ СИСТЕМЫ ПЛАТЕЖЕЙ

В работе представлена информация об электронных системах платежей. Рассмотрены достоинства системы и требования к ней, а так же варианты решения данных требований

ДИНАМІКА ЧИСЕЛЬНОСТІ ГРОМАД РИМО-КАТОЛИЦЬКОЇ ЦЕРКВИ НА ПІВДНІ УКРАЇНИ В 20-30-ТІ РР. ХХ СТ.

У статті автором проаналізовано динаміку чисельності громад Римо-католицької церкви на Півдні України в 20-30-ті рр. ХХ ст. Визначено політичні та демографічні фактори, що впливали на зміни чисельності громад в регіоні.In the article the author analyzed the dynamics of numberRoman-Catholic Church’s societies in the South Ukraine in 20s-30s of the XXth century. The political and demographic factors which influence on change of number societies in regionwere defined

К ПРОБЛЕМЕ НАУЧНОЙ ОРГАНИЗАЦИИ ТРУДА ПЕДАГОГА

У статті розглянуті питання наукової організації праці педагога, особливості НОП в освітній діяльності, проблеми компетентності вчителі в умовах сучасної школи.The article deals with scientific organization of work of the teacher, especially under examination in educational activities, problems of competence of teachers in modern schools

Измерение активной составляющей электрохимического импеданса растворов с использованием миниатюрной двухэлектродной кондуктометрической ячейки

Показана возможность точного измерения активной составляющей электрохимического импеданса растворов электролитов при использовании импульсного напряжения большой скважности и большой скорости нарастания напряжения. Определены условия, при которых погрешность измерения проводимости раствора по амплитуде силы тока при использовании миниатюрных датчиков с постоянной кондуктометрической ячейки до 1000 м-1 не превышает 0,01 %. Сделан вывод о возможности использования миниатюрных кондуктометрических датчиков для прецизионных кондуктометрических измерений

Real-time auralization for performers on virtual stages

This article presents an interactive system for stage acoustics experimentation including considerations for hearing one's own and others' instruments. The quality of real-time auralization systems for psychophysical experiments on music performance depends on the system's calibration and latency, among other factors (e.g. visuals, simulation methods, haptics, etc). The presented system focuses on the acoustic considerations for laboratory implementations. The calibration is implemented as a set of filters accounting for the microphone-instrument distances and the directivity factors, as well as the transducers' frequency responses. Moreover, sources of errors are characterized using both state-of-the-art information and derivations from the mathematical definition of the calibration filter. In order to compensate for hardware latency without cropping parts of the simulated impulse responses, the virtual direct sound of musicians hearing themselves is skipped from the simulation and addressed by letting the actual direct sound reach the listener through open headphones. The required latency compensation of the interactive part (i.e. hearing others) meets the minimum distance requirement between musicians, which is 2 m for the implemented system. Finally, a proof of concept is provided that includes objective and subjective experiments, which give support to the feasibility of the proposed setup