Beyond reverberation time: Toward a new geometric approach to room acoustics

2021 ◽  
Vol 150 (4) ◽  
pp. A118-A118
Author(s):  
Zackery Belanger
Keyword(s):  
Geometric Approach ◽  
Room Acoustics ◽  
Reverberation Time

Quantifying Non-Linearity in Early Decay Curves of Measured and Computer-Modeled Room Impulse Responses of a Highly Non-Diffuse Room Exhibiting Flutter Echo

2020 ◽  
Author(s):  
Heather L. Lai ◽  
Brian Hamilton
Keyword(s):  
Linear Regression ◽  
Computer Modeling ◽  
Impulse Response ◽  
Decay Curve ◽  
Sound Field ◽  
Energy Decay ◽  
Room Acoustics ◽  
Reverberation Time ◽  
Sound Fields ◽  
Regression Curves

Abstract This paper investigates the use of two room acoustics metrics designed to evaluate the degree to which the linearity assumptions of the energy density curves are valid. The study focuses on measured and computer-modeled energy density curves derived from the room impulse response of a space exhibiting a highly non-diffuse sound field due to flutter echo. In conjunction with acoustical remediation, room impulse response measurements were taken before and after the installation of the acoustical panels. A very dramatic decrease in the reverberation time was experienced due to the addition of the acoustical panels. The two non-linearity metrics used in this study are the non-linearity parameter and the curvature. These metrics are calculated from the energy decay curves computed per octave band, based on the definitions presented in ISO 3382-2. The non-linearity parameter quantifies the deviation of the EDC from a straight line fit used to generated T20 and T30 reverberation times. Where the reverberation times are calculated based on a linear regression of the data relating to either −5 to −25 dB for T20 or −5 to −35 dB for T30 reverberation time calculations. This deviation is quantified using the correlation coefficient between the energy decay curve and the linear regression for the specified data. In order to graphically demonstrate these non-linearity metrics, the energy decay curves are plotted along with the linear regression curves for the T20 and T30 reverberation time for both the measured data and two different room acoustics computer-modeling techniques, geometric acoustics modeling and finite-difference wave-based modeling. The intent of plotting these curves together is to demonstrate the relationship between these metrics and the energy decay curve, and to evaluate their use for quantifying degree of non-linearity in non-diffuse sound fields. Observations of these graphical representations are used to evaluate the accuracy of reverberation time estimations in non-diffuse environments, and to evaluate the use of these non-linearity parameters for comparison of different computer-modeling techniques or room configurations. Using these techniques, the non-linearity parameter based on both T20 and T30 linear regression curves and the curvature parameter were calculated over 250–4000 Hz octave bands for the measured and computer-modeled room impulse response curves at two different locations and two different room configurations. Observations of these calculated results are used to evaluate the consistency of these metrics, and the application of these metrics to quantifying the degree of non-linearity of the energy decay curve derived from a non-diffuse sound field. These calculated values are also used to evaluate the differences in the degree of diffusivity between the measured and computer-modeled room impulse response. Acoustical computer modeling is often based on geometrical acoustics using ray-tracing and image-source algorithms, however, in non-diffuse sound fields, wave based methods are often able to better model the characteristic sound wave patterns that are developed. It is of interest to study whether these improvements in the wave based computer-modeling are also reflected in the non-linearity parameter calculations. The results showed that these metrics provide an effective criteria for identifying non-linearity in the energy decay curve, however for highly non-diffuse sound fields, the resulting values were found to be very sensitive to fluctuations in the energy decay curves and therefore, contain inconsistencies due to these differences.

scholarly journals Estimation of Reverberation Time in Classrooms Using the Residual Minimization Method

2017 ◽  
Vol 42 (4) ◽  
pp. 609-617 ◽  
Author(s):  
Artur Nowoświat ◽  
Marcelina Olechowska
Keyword(s):  
Computer Simulations ◽  
Acoustic Field ◽  
Analytical Methods ◽  
Room Acoustics ◽  
Reverberation Time ◽  
Minimization Method ◽  
Theoretical Methods ◽  
Residual Minimization

Abstract The objective of the residual minimization method is to determine a coefficient correcting the Sabine’s model. The Sabine’s equation is the most commonly applied formula in the designing process of room acoustics with the use of analytical methods. The correction of this model is indispensable for its application in rooms having non-diffusive acoustic field. The authors of the present paper will be using the residual minimization method to work out a suitable correction to be applied for classrooms. For this purpose, five different poorly dampened classrooms were selected, in which the measurements of reverberation time were carried out, and for which reverberation time was calculated with the use of theoretical methods. Three of the selected classrooms had the cubic volume of 258.5 m3 and the remaining two had the cubic volume of 190.8 m3. It was sufficient to estimate the correction for the Sabine’s equation. To verify the results, three other classrooms were selected, in which also the measurements of reverberation time were carried out. The results were verified by means of real measurements of reverberation time and by means of computer simulations in the program ODEON.

Speech accommodation to room acoustics: Reverberation time and clarity

2016 ◽  
Vol 139 (4) ◽  
pp. 1980-1980
Author(s):  
Pasquale Bottalico ◽  
Simone Graetzer ◽  
Eric J. Hunter
Keyword(s):  
Room Acoustics ◽  
Reverberation Time

scholarly journals Changes of Voice Production in Artificial Acoustic Environments

2021 ◽  
Vol 7 ◽  
Author(s):  
Tomás Sierra-Polanco ◽  
Lady Catherine Cantor-Cutiva ◽  
Eric J. Hunter ◽  
Pasquale Bottalico
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Dynamic Range ◽  
Vocal Tract ◽  
Production Systems ◽  
Pressure Level ◽  
Room Acoustics ◽  
Reverberation Time ◽  
Voice Production ◽  
Vocal Control

The physical production of speech level dynamic range is directly affected by the physiological features of the speaker such as vocal tract size and lung capacity; however, the regulation of these production systems is affected by the perception of the communication environment and auditory feedback. The current study examined the effects of room acoustics in an artificial setting on voice production in terms of sound pressure level and the relationship with the perceived vocal comfort and vocal control. Three independent room acoustic parameters were considered: gain (alteration of the sidetone or playback of one’s own voice), reverberation time, and background noise. An increase in the sidetone led to a decrease in vocal sound pressure levels, thus increasing vocal comfort and vocal control. This effect was consistent in the different reverberation times considered. Mid-range reverberation times (T30 ≈ 1.3 s) led to a decrease in vocal sound pressure level along with an increase in vocal comfort and vocal control, however, the effect of the reverberation time was smaller than the effect of the gain. The presence of noise amplified the aforementioned effects for the variables analyzed.

Field measurement of reverberation time and average absorption of one high-rise building room by road traffic noise penetrating facade

2021 ◽  
Vol 263 (4) ◽  
pp. 2875-2886
Author(s):  
Jiping Zhang ◽  
Zheming Wang ◽  
Heng Ma ◽  
Weike Wang
Keyword(s):  
Field Measurement ◽  
Road Traffic ◽  
Traffic Noise ◽  
Field Method ◽  
Room Acoustics ◽  
Road Traffic Noise ◽  
Reverberation Time ◽  
Field Weakening ◽  
High Rise ◽  
High Rise Building

The facade insulation (FI) is one choice for Road traffic noise (RTN) at a high-rise accommodation building nearby a motor road. The weakness of FI is from window, so the window insulation (WI) is also a prioritized descriptor. ISO16283-3 states a field method to measure FI using RTN. However, in room acoustics, besides FI, reverberation time (RBT) or indoor average sound absorption (IASB) are another two un-ignorable descriptors. When the value of IASB is small, the indoor noise is not only contributed from penetrating façade RTN, but also supplemented by the residual sound from high reverberation field, weakening FI. As a parallel to ISO16283-3, this paper suggests an engineering method to measure RBT and IASB of one high-rise building room close to a motor road by penetrating façade RTN. It can supply a convenient tool for the field measurement of RBT and IASB with RTN. At the end, we made a field measurement of RBT, IASB, and WI at a hotel room nearby a viaduct in Hangzhou of China, assistant to adjust RBT or IASB and WI so as to improve the sound quality of the hotel. Further, the method can extend to the lines of rail, aviation, and shipping.

Simulation of Different Acoustic Lecture Room Designs

2014 ◽  
Vol 899 ◽  
pp. 505-508
Author(s):  
Kateřina Komínková ◽  
Michal Papranec ◽  
Libor Šteffek
Keyword(s):  
Simulation Program ◽  
Room Acoustics ◽  
Internal Environment ◽  
Reverberation Time ◽  
Good Design ◽  
Structural Modifications ◽  
Current State ◽  
Lecture Room

Room acoustics of the internal environment is among others an important part of good design. The paper deals with the simulation of lecture room acoustic structural modifications. In specific lecture room was measured reverberation time of the current state. Based on the results of the measurements several design variations of acoustic structures have been made to suit the room with a standard requirements for recitation. Subsequently, these measures were modeled and examined in the simulation program. The paper points to the importance of simulations in design of interior acoustic adjustments.

Computer Simulations of Room Acoustics in Sporting Facilities

2013 ◽  
Vol 649 ◽  
pp. 57-60
Author(s):  
Zuzana Kolářová ◽  
Libor Šteffek ◽  
František Vajkay
Keyword(s):  
Room Acoustics ◽  
Building Structures ◽  
Reverberation Time ◽  
Acoustic Parameters ◽  
Main Emphasis ◽  
Master Thesis ◽  
Sporting Activities ◽  
The Individual ◽  
The Given ◽  
Indoor Spaces

The paper is focused on a solution with regards to acoustic problems inside of facilities for sporting activities. The evaluation of the acoustic parameters of the interior was done within a project called "Badminton Centre with Facilities", which was part of a master thesis at the Institute of Building Structures of the Faculty of Civil Engineering, BUT Brno. The given solution and design took into account not only the requirements given by the legislation dealing with building acoustics, but the aesthetical viewpoint of the individual acoustically absorbing surfaces also. The simulations were done in Odeon Auditorium software, which is specialized for the modelling of indoor spaces of buildings. The results of simulations are presented in octave bands with a frequency range of 250-2000 Hz, while the main emphasis is put onto the monitoring of the reverberation time.

Problems in the Designing of Acoustic Properties of Musical Rehearsals

2016 ◽  
Vol 861 ◽  
pp. 519-526
Author(s):  
Dušan Katunský ◽  
Jana Katunská ◽  
Iveta Bullová ◽  
Richard Germánus
Keyword(s):  
Noise Pollution ◽  
Acoustic Properties ◽  
Room Acoustics ◽  
Sound Insulation ◽  
Building Structures ◽  
Internal Environment ◽  
Reverberation Time ◽  
Acoustic Performance ◽  
Methods Of Calculation ◽  
Building Acoustics

Content of the post is to describe the creation of building structures, typology, internal environment, and internal wall coverings music rehearsal for optimal acoustic performance. One of the aspects of its internal environment is reverberation time. For this variable there are several methods of calculation. Article gives an indication of how the music was the laboratory building in the center of the music created and what problems the authors in its proposal met. Article contents and solving spatial and building acoustics model music musical rehearsal building downtown. Calculation fully respects Slovak standards valid for the design of room acoustics, as well as hygiene regulations on noise pollution. Acoustically treated room should serve as a laboratory for musical performance. If the building is more proof is needed to solve the sound insulation (building acoustics) that these areas do not interfere with each other. In addressing acoustics of testing can’t talk about bad or good acoustics, but rather on the season and out of corresponding with room acoustics, respectively, with activities in it.

scholarly journals Indicative Assessment of Classroom Acoustics in Schools Built in Reinforced Concrete Technology on The Example of a School Building in Zabrze

2021 ◽  
Vol 1203 (2) ◽  
pp. 022007
Author(s):  
Marcelina Olechowska ◽  
Artur Nowoświat ◽  
Michał Marchacz ◽  
Karolina Kupczyńska
Keyword(s):  
Reinforced Concrete ◽  
Room Acoustics ◽  
School Building ◽  
Reverberation Time ◽  
Concrete Technology ◽  
Classroom Acoustics ◽  
Low Frequencies ◽  
Level Of Knowledge ◽  
The Republic ◽  
Acoustic Conditions

Abstract In view of room acoustics in schools, not only noise level is extremely important, but also the reverberation conditions in a given room. Such conditions affect the intelligibility of speech, which determines the acquisition level of knowledge conveyed by the teacher. The article presents problems of school classroom acoustics for a building made in reinforced concrete technology on the example of a school building in Zabrze. For the research, we selected one of schools established in 1970s as a memorial of the Millennium Jubilee of the Republic of Poland. The obtained results of the reverberation time indicate poor acoustic conditions, which, regrettably, is quite common in Polish schools. For low frequencies, the reverberation time of a classroom for teaching mathematics was over 2 seconds, and for medium frequencies it was almost 2 seconds. The article presents the acoustics of the studied classrooms without proposals of acoustic adaptation.

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