Reverberation time measuring methods

Jambrošić, Kristian; Horvat, Marko; Domitrović, Hrvoje

doi:10.1121/1.2934829

Cited by 16 publications

(15 citation statements)

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“…The reverberation time has always been the basic indicator of acoustical behavior [12]. In the present work, we measured RT30 (the time in which the sound intensity decreases by 30 dB) as Li and Lam [13].…”

Section: Description and Experimentsmentioning

confidence: 91%

Conference Room Reverberation Time Correction Using Helmholtz Resonators Lined with Absorbers

Arefi

Ghiasi

Ghaffari

et al. 2014

Shock and Vibration

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Echo and sound resonance in a conference room cause obscure speech and make listeners tired. Thus, the acoustical properties of a conference room are vitally important. The conference room 412 at Sharif University Physics Department failed to meet basic acoustical standards. The aim of this research is to improve reverberation time (RT) of the conference room using Helmholtz resonators with defined dimensions, diffusers, and sound absorbers. Helmholtz resonators are widely used to absorb sound noise especially at low frequencies. They are particularly useful when noise has a narrow-frequency band. One of the advantages of using Helmholtz resonators is their capacity to be tuned on different frequencies. We enhanced acoustical properties of Helmholtz resonators using proper absorbers and diffusers. In order to decrease the RT, a large number of Helmholtz resonators have been made and installed in proper positions in the conference room. The RT was measured before and after installation. The measurements indicate that the acoustical characteristics of the conference room have been significantly improved.

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Section: Description and Experimentsmentioning

confidence: 91%

Conference Room Reverberation Time Correction Using Helmholtz Resonators Lined with Absorbers

Arefi

Ghiasi

Ghaffari

et al. 2014

Shock and Vibration

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show abstract

“…In regard to the measurement of acoustic parameters, research by Fausti and Farina [77] revealed differences between RT measurements with a gun and techniques utilizing a dodecahedron speaker especially in the low-frequency range (more than 0.3 s difference in the 125 Hz octave band). A study by Jambrosic et al [76] revealed differences in the measurement of RT between pistol shots of different calibers. In a study by Bradley [92], comparisons between measured values and calculated values (RT, C 80 , C 50 and C 35 ) based on ideal exponential decays showed that such predictions are not particularly accurate but give an indication of the mean trends.…”

Section: Gunshotmentioning

confidence: 99%

“…In regard to the measurement of acoustic parameters, there are several studies where this matter is addressed [68,[75][76][77][78]. A study by Jambrosic et al [76] showed that for measurements of reverberation time (RT) with the use of a balloon, results will deviate in the low-frequency range in rooms, compared with studies using standard techniques (dodecahedron speaker). However, if the measured room is large and reverberant, smaller deviations are to be expected.…”

Section: Balloonmentioning

confidence: 99%

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Papadakis

Stavroulakis

2019

Applied Sciences

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An omnidirectional source is required in many acoustic measurements. Commonly a dodecahedron speaker is used but due to various factors (e.g., high cost, transportation difficulties) other acoustic sources are sometimes preferred. In this review, fifteen acoustic source alternatives to a dodecahedron speaker are presented while emphasis is placed on features such as omnidirectionality, repeatability, adequate sound pressure levels, even frequency response, accuracy in measurement of acoustic parameters and fulfillment of ISO 3382-1 source requirements. Some of the alternative acoustic sources have the appropriate features to provide usable results for acoustic measurements, some have acoustic characteristics better than a dodecahedron speaker (e.g., omnidirectionality in the high-frequency range), while some can potentially fulfill the ISO 3382-1 source requirements. Collected data from this review can be used in many areas (e.g., ISO measurements, head-related transfer functions measurements) for the appropriate selection of an acoustic source according to the expected use. Finally, suggestions for uses and future work are given aimed at achieving further advances in this field.

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“…As opposed to standardized measurements, the loudspeakers were not omnidirectional. However, it has been shown that the use of sound sources with directional patterns differing from omnidirectional has insignificant influence on reverberation time measurements if the measured room is large and reverberant, and the sound field in the room is diffuse [45]. Moreover, to further compensate the use of non-omnidirectional sound sources, the loudspeakers were directed towards boundary diffusers.…”

Section: Reverberation Roommentioning

confidence: 99%

Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters

2019

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The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In this study, the impact of the placement of the absorption material in a room was measured in a reverberation room and in a mockup classroom. The results show that absorption material is less efficient if it is mounted to the corners or on the edges between the walls and ceiling, if the sound field is more or less diffuse. If the room modes dominate the sound field, the most efficient location for the sound-absorbing material was found at one of the surfaces causing the modes. The results help acoustical consultants to place the absorption material in optimal locations and, generally, minimize the amount of material and save costs.

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Reverberation time measuring methods

Cited by 16 publications

References 0 publications

Conference Room Reverberation Time Correction Using Helmholtz Resonators Lined with Absorbers

Conference Room Reverberation Time Correction Using Helmholtz Resonators Lined with Absorbers

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters

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