scholarly journals Investigation on acceptable reverberation time at various frequency bands in halls that present amplified music

2018 ◽  
Vol 129 ◽  
pp. 104-107 ◽  
Author(s):  
Niels Werner Adelman-Larsen ◽  
Cheol-Ho Jeong ◽  
Bård Støfringsdal
Acta Acustica ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 3
Author(s):  
Andrea Andrijašević

This study focuses on an unexplored aspect of the performance of algorithms for blind reverberation time (T) estimation – on the effect that speech signal’s phonetic content has on the value of the estimate of T that is obtained from the reverberant version of that signal. To this end, the performance of three algorithms is assessed on a set of logatome recordings artificially reverberated with room impulse responses from four rooms, with their T20 value in the [0.18, 0.55] s interval. Analyses of variance showed that the null hypotheses of equal means of estimation errors can be rejected at the significance level of 0.05 for the interaction terms between the factors “vowel”, “consonant”, and “room”, while the results of Tukey’s multiple comparison procedure revealed that there are both some similarities in the behaviour of the algorithms and some differences, where the latter are stemming from the differences in the details of algorithms’ implementation such as the number of frequency bands and whether T is estimated continuously or only on the selected, the so-called speech decay, segments of the signal.


2001 ◽  
Vol 7 (2) ◽  
pp. 166-173
Author(s):  
Vidmantas Dikavičius ◽  
Raimondas Bliūdžius

The report deals with a task of investigating and adjusting acoustic parameters of the reverberant chambers of recently built laboratory for measuring sound insulation properties of building elements (windows, doors). The reverberation time values in the source and receiving empty rooms were measured at 16 one-third-octave frequency bands. It was determined that they significantly exceed the recommended ones. After a number of measurements the reverberation time was adjusted to the allowable limits. An optimum combination of loudspeaker positions in the source room with respect to the best acoustic field diffusivity has been experimentally found. Repeatability values r were calculated from the measurements of sound reduction index of plastic window conducted under repeatability conditions. At the 16 one-third-octave frequency bands they show a good precision of the test equipment.


2016 ◽  
Vol 136 (7) ◽  
pp. 621-627
Author(s):  
Akiko Takahashi ◽  
Akihiro Yamagata ◽  
Jun Imai ◽  
Shigeyuki Funabiki

2015 ◽  
Vol E98.B (5) ◽  
pp. 773-782 ◽  
Author(s):  
Ngochao TRAN ◽  
Tetsuro IMAI ◽  
Yukihiko OKUMURA

1997 ◽  
Vol 51 (6-7) ◽  
pp. 25-27
Author(s):  
V. N. Frankov ◽  
G. Y. Osokin ◽  
O. V. Gavrentiuk ◽  
A. I. Samokhvalov

This paper discusses the use of Maximum Correlation kurtosis deconvolution (MCKD) method as a pre-processor in fast spectral kurtosis (FSK) method in order to find the compound fault characteristics of the bearing, by enhancing the vibration signals. FSK only extracts the resonance bands which have maximum kurtosis value, but sometimes it might possible that faults occur in the resonance bands which has low kurtosis value, also the faulty signals missed due to noise interference. In order to overcome these limitations FSK used with MCKD, MCKD extracts various faults present in different resonance frequency bands; also detect the weak impact component, as MCKD also dealt with strong background noise. By obtaining the MCKD parameters like, filter length & deconvolution period, we can extract the compound fault feature characteristics.


In this paper, a 15* 80 sized antenna is designed over a paper substrate to test its flexible properties. The proposed antenna feed by a grounded coplanar waveguide(GCPW) is stimulated and the measured results show the operating Dual Band of the antenna cover(3.34-3.62 GHz) and (5.92-6.24 GHz) with the reflection coefficient |S11|< -15dB.These frequency bands operate over SHF bands and hence supports Fixed Mobile Communication and WLAN applications.


2020 ◽  
Vol 10 (4) ◽  
pp. 501-506
Author(s):  
Monisha Ghosh ◽  
Arindam Biswas ◽  
Aritra Acharyya

Aims:: The potentiality of Multiple Quantum Well (MQW) Impacts Avalanche Transit Time (IMPATT) diodes based on Si~3C-SiC heterostructures as possible terahertz radiators have been explored in this paper. Objective:: The static, high frequency and noise performance of MQW devices operating at 94, 140, and 220 GHz atmospheric window frequencies, as well as 0.30 and 0.50 THz frequency bands, have been studied in this paper. Methods: The simulation methods based on a Self-Consistent Quantum Drift-Diffusion (SCQDD) model developed by the authors have been used for the above-mentioned studies. Results: Thus the noise performance of MQW DDRs will be obviously better as compared to the flat Si DDRs operating at different mm-wave and THz frequencies. Conclusion:: Simulation results show that Si~3C-SiC MQW IMPATT sources are capable of providing considerably higher RF power output with the significantly lower noise level at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands as compared to conventional flat Si IMPATT sources.


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