Room Acoustic Software Research Articles

Acoustic Analysis of the Masjid at Necmettin Erbakan University Köyceğiz Campus in Konya

In this study, the passive acoustic performance of Necmettin Erbakan University Köyceğiz Campus Masjid was investigated. Designed as the largest masjid of the city with a capacity of 15,000 people and a volume of 43,200 m3, the masjid, which has traces of Seljuk, Ottoman and Modern architecture. is built as a complex at a location overlooking the city in the Meram District of Konya City, Turkiye. The aim of the study is to determine the acoustic comfort conditions by considering all the activities in the masjids as a whole. Within the scope of the study, the acoustic performance of the masjid was evaluated by determining different source and receiver points for each mode of activity. As a method, the chosen masjid was simulated with ODEON Room Acoustics Software Ver. 14.04 software. Objective room acoustic parameters were analysed in three groups. These are sound energy ratio parameters (reverberation time (RT), early decay time (EDT), clarity (C50, C80), lateral fraction (LF80)), speech intelligibility parameters (definition (D50), speech transmission index (STI)) and sound strength parameters (strength (G)). The results obtained were compared with precedent studies in the literature. In comparison with the acoustic values obtained in other masjid/mosque buildings, it was reported that, while the speech intelligibility of other masjids/mosques was at a satisfactory level, the masjid under consideration was at a poor level in both fully occupied and unoccupied conditions. In the analysis made for reverberation time, it was seen that the masjid discussed in this study showed similar characteristics to other masjids/mosques globally. As a result, it was determined that the dimensions of the surfaces forming the mihrab, the minbar design and the depths of the mahfil overhangs are effective regarding the acoustics of the masjid, and the design of curved surfaces should be carried out in a way that does not cause focusing problems. In addition, suggestions that can give guidelines to modern masjid designs have been put forward.

Analyzing the impact of classroom design factors on acoustic comfort in higher education hybrid learning environments

The vitality of hybrid learning classrooms has escalated due to enabling factors including advancements in technology, the demand for flexible education, and responses to global crises. However, the inadequate preparation for implementing hybrid classrooms raises concerns about students' ability to understand speech due to a lack of attention to the importance of acoustic quality. As a result, this study aims to investigate the impact of classroom design factors, such as ceiling height, occupancy, and spatial layout configuration, on hybrid classroom acoustic performance. The field measurement data acquired from multiple classrooms was utilized for analysis. The impact of design factors on acoustic parameters, which comprise reverberation time (RT), speech transmission index (STI), and speech clarity (C50), was analyzed through simulation using ODEON room acoustic software. The simulation was conducted based on two distinctive categorizations, which were determined by the size of the classrooms. The outcomes revealed that the design factors consisting of ceiling height, occupancy level, and spatial layout arrangements influenced the acoustic performance at various microphones' locations in hybrid learning classrooms. Although the analysis effectively upholds students' learning experience and performance, it is valuable for designers and educational institutions to establish adequate acoustic qualities for hybrid learning environments.

An open-source time-domain wave-based room acoustic software in Python based on the nodal discontinuous Galerkin method

In this work, we introduce an open-source implementation of a time-domain wave-based room acoustic modeling software package, named DG_RoomAcoustics. In this software, the linear acoustic equations are spatially discretized by the nodal discontinuous Galerkin method, and are integrated in time by either the explicit Runge-Kutta or the arbitrary high-order derivatives (ADER) integration schemes. Following the principles of object-oriented programming paradigm, the software is structured to ensure generic applicability and to facilitate future extensions with additional functionalities (e.g., different time integration schemes, boundary conditions). A comprehensive presentation of the physical and numerical aspects of the problem is provided. A detailed exposition of the code structure and components is presented, all of which are released under an open-source license, fostering community feedback and collaborative contributions for ongoing improvements. A brief overview of the current capabilities of the software is introduced. Future work regarding possible functionality extensions and performance optimizing are discussed.

Case study: Computer modeling the noise produced by a future food court radiated to nearby existing offices

Lately, there’s an increase in the co-existence of spaces of different usage with acoustical challenge. Throughout 2016 to 2018, the 2nd floor of the Complexe Les Ailes, in Montreal, underwent a fit-out to become a food court. At its center, there is an elliptical atrium where all levels are can be viewed. There are existing offices above the food court separated by a glass pane. The purpose of this study was to evaluate the noise generated by human activities in the future food court to the adjacent offices and recommend noise control elements if needed. Multiple sound samples were taken at existing food courts to quantify the sound level. Simulations were done with ODEON, a room acoustic software, to evaluate the sound level produced by different activities. On-site measurements were conducted to calibrate the existing conditions with the 3D ODEON model. Finally, noise reduction tests were undertaken to determine the sound levels that would be radiated in the offices by the activities in the food court. To reduce noise disturbance in the offices, acoustical treatment under the ceiling of the food court was recommended and the 3rd and 4th floor glass panes composition would have to be improved.

Sandiaoling eco-friendly tunnel soundscape and virtual reality analysis

Soundscape of Sandiaoling Ecological Tunnel, a 1.852 km bike path tunnel, has been studied for the taxonomy of sound sources, equivalent sound pressure levels, and the perceived sonic quality. This paper focuses on examining simulated sound source propagations in the tunnel using both omni and directional sound sources with Odeon Room Acoustic software. Additionally, it compares the specific receivers’ auralizations with in situ recorded sounds in a virtual reality model along with a questionnaire to evaluate the distinctions between the two. The preliminary results showed that the simulated sonic quality in tunnel is less reverberant than expected. Proximity of receivers to sound source, the boundary of air to source and receivers inside tunnel as well as the absorption, scattering and transparency coefficients of materials used in simulated model are adjusted. Future work will explore into audio post-production and visual effects.

Room acoustic computer modeling—A case study to compare industry standard software with measured results

This paper extends a previous publication presented at the Inter-Noise 2005 conference [1] and investigates the predictive performance of some industry standard room acoustic software packages compared with measurements. The case study specifically examines the Twyford Theatre, comparing predictions of room acoustic parameters obtained from ODEON, EASE, and Treble software with measurements. To conduct the study, impulse response measurements were performed in the theater using the swept sine method. Architectural drawings and on-site inspection measurements were utilized to construct ODEON, EASE, and Treble models for prediction purposes. The findings of this study provide insights into the predictive performance of these industry standard room acoustic software packages with comparison to measured results. C. Field and S. Shimada, Acoustic Computer Modelling: A Case Study to Compare Predictions by CATT and Odeon with Measured Results, Inter-Noise 2005.

Validation of an image source method room acoustics software in a highly reverberant room with a directional impulsive noise source

Exposure to impulsive noise sources is common during routine operations military contexts. This type of noise exposure is prevalent in training procedures carried out with small caliber firearms in both indoor and outdoor settings. Typically, hearing protection is required to mitigate hearing damage risk to military personnel. Consequently, proper prescription of hearing protection required bioenvironmental engineers and industrial hygienists to travel and collect data in situ which can be time consuming and expensive. As such, the researchers at the 711th Human Performance Wing of the United States Air Force Research Lab have developed a software named the Shooting Range Impulse Noise Calculator (ShRINC). The ShRINC software provides the capability to simulate high fidelity acoustic levels within indoor and outdoor shooting ranges with directional impulsive noise sources. This is accomplished by leveraging principles from Image Source Room (ISM) based room acoustics and combining them with weapon source models with complicated directivity patterns. In this work, validation will be completed by comparing results collected in a highly reverberant facility with the M4A1 firearm operating blank rounds. An investigation into the proper order for the ISM solver will be analyzed and sound exposure levels between the simulation and measured data will be compared.

Soundscape of Sandiaoling Ecological Tunnel

The Sandiaoling Ecological Tunnel, originally an abandoned railway, has been transformed into a 1852 m long ecological bike path. Constructed with stones and bricks, the tunnel now features an elevated bike path supported by threaded iron rods, with a gentle water flow beneath. As the tunnel has two main sections and an open transition area in between it, the entrance (open), the middle of the tunnel (enclosure), near the tunnel exit (semi-open), and the transition area between the two main sections are selected as the four soundscape study locations. The study follows ISO-12913 soundscape study method to document essential sound sources, paths, and levels. Odeon Room Acoustic Software is used to study the simulated sound source propagations. The research documents a taxonomy of sound sources, encompassing both natural and man-made sounds. The tunnel's atmosphere is characterized by quietude, monotony, coldness, and resonance. The average equivalent sound pressure level in the four measured locations is 59dBA. Frequency spectrums and simulated reflection patterns are also examined. During the soundwalk, the overall listening impression of the tunnel is described as delightful, relaxing, peaceful, and harmonious with nature. The atmosphere inside the tunnel evokes a sense of serenity and tranquility.

Effect of reference value and ensemble size on perception of reverberation in simulated listening environments

Reverberation time is an important metric characterizing one of the key differences between performance venues caused by various furnishing, materials, and geometry within such spaces. To justify alterations to a venue, architects and acousticians refer to the just-noticeable-difference (JND) of reverberation time, cited in the ISO 3382-1 room acoustics standard as 5% of the reference value. This JND was determined experimentally using impulsive noise with varying reverberation. In real performance venues, overlapping and simultaneous sounds are more common than isolated impulses. As such, the JND noted in literature may not provide a complete picture of perceived reverberation for persons listening to live performed music. For this study, multiple test methods were evaluated by using different reference reverberation times as well as using a variety of instrumentation and genres for musical signals. Results were generated using test participants who were asked to listen to multiple virtual soundfields and provide subjective evaluation. Reverberant soundfields were recreated in an anechoic listening environment and auralizations were produced using ODEON room acoustics software. Results indicated statistically significant mean differences in perceived reverberation across instrumentation subsets, genre subsets, as well as through different testing configurations. [Work supported by The Paul S. Veneklasen Research Foundation.]

A Comparison of Acoustical Performance Between Traditional and Modern Church

Due to various worship approaches, churches' plans and designs have evolved over time.Intraditional churches, the chancel is where the preacher and choir are while the nave is where the audience is seated. The modern churches on the other hand usually follow the auditorium layout, where the chancel is replaced by a stage. The stage serves asa space for the musical worship and performances, other than preaching by the pastors. In acoustical terms, the chancel and the stage are known as the sound source and the audience is the sound receiver. It is essential to understand the relationship between the differences in the characteristics of traditional and modern churches and the impact on their acoustical performance.Two churches with different layout (cruciform and rectangular) from traditional and modern churches in Malaysia were selected to run a computer simulation using ODEON Room Acoustic Software. The results were then reviewed and analyzedin acoustical parameters: (i) Reverberation Time (RT) and (ii) Speech Transmission Index (STI). Smaller church scored better in STI thus it is better for speech driven worship service as while bigger church scored better in RT thus it is more ideal for musical worship. In addition, the existing materials found in modern churches improved the overall acoustical performances. In conclusion, the church acoustical performance is affected by factors like the volume, distance between the sound origin, receivers and the surrounding walls, total absorption area and types of surface material and its absorption coefficient.

Effect of musical instrumentation on perception of reverberation in simulated listening environments

The reverberance of a performance venue is often characterized by an important metric, reverberation time. In order for architects, acousticians, and performers to better understand the value of knowing and predicting the reverberation time in different spaces, the just-noticeable-difference (JND) is often cited. The established JND for reverberation time is approximately 5% of the reference reverberation, noted in the standard ISO 3382-1. This value was determined using impulsive sound, meaning it may not provide a complete picture for applications related to music. This study aimed to evaluate several elements of musical performance that may alter the perception of reverberation in a simulated listening environment. Primarily, the effect of instrumentation was investigated, including the use of solo, small ensemble, full orchestra, and vocal recordings for comparison. Results were generated using test participants listening to multiple soundfields and providing subjective evaluation. Reverberant soundfields were created in an anechoic listening environment and auralizations were produced using ODEON room acoustics software. Results indicated statistically significant mean differences in reverberation perception between musical instrumentation groups used during experiments. [Work supported by The Paul S. Veneklasen Research Foundation.]

Impact of Mihrab geometry on the acoustics of the mosque

Mihrab is a niche in the wall of a mosque that indicates the qibla, the direction of the Kaaba in Mecca towards which Muslims should face when praying. The wall in which a mihrab appears is thus the "qibla wall". Mihrab geometry has an impact on daily prayer recitation and others. This paper investigates the impact of new type of the Mihrab geometry on the acoustics of the mosque. Flat wall and 7 types of mihrab were modeled. Polar response measurements were carried out using 1:10 scale model. Measurements had been realized using 1:10 omni-directional sound source and Dirac room acoustics software. It is found that flat wall and Mihrab with trapezium and triangle shapes can generate a uniform polar response over the frequency range we are interested in (500-2000 Hz).

The New Rady Shell at Jacobs Park in San Diego

Located along the waterfront at Jacobs Park, the Rady Shell is the summer home for the San Diego Symphony. The shell opened in summer 2021 as a unique outdoor venue in downtown San Diego. When not used for performances, the lawn is open to the public. Salter provided input on the physical acoustics and technology components within the shell. This presentation focuses on the interior acoustics of the shell. The shell utilizes the first Meyer Sound Constellation system designed for stage acoustics in an outdoor venue. To enhance the experience for the symphony on stage, a mixture of reflective and diffusive panels were used to provide some natural early reflections. During design, the ODEON Room Acoustics software was used to predict the acoustical response on the stage. Above the stage, the shell features a checkerboard pattern of absorptive and reflective panels. At the lawn, Salter worked with L'Acoustics to design a sound system that focused sound on the audience to reduce impact to the neighboring properties.

Analysis of the acoustical environment of classrooms in three brazilian public schools through measurements and 3d simulation

The present study analyses the outdoor and indoor sound pressure levels (SPL) and the reverberation time (RT) measured in three Brazilian public classrooms. For the SPL, a sound level analyzer (class II) was used, and for the RT it was used a smartphone for the measurements. The sound sources were the impulses of bursting balloons and the data was processed in a MatLab toolbox (ITA-Toolbox). The classrooms were also simulated in an open source modeling software (I-SIMPA), using ray-tracing principles. Based on the results of the simulations, supported by the low-cost measurements, it was observed that the classroom didn't reach the national standards for classroom acoustics. Some improvements were designed with sustainable materials in order to reach the lower limits of the standards using the same room acoustics software. It was observed that the low-cost measurements helped on the diagnosis of classroom's acoustic issues which was also verified in the 3D simulation. This procedure showed itself as a cheap solution for classroom acoustic designs.

The Assessment of Acoustical Characteristics for Recent Mosque Buildings in Erbil City of Iraq

The study of mosque acoustics, concerning acoustical features, sound quality for speech intelligibility, and additional practical acoustic criteria, is commonly overlooked. Acoustic quality is vital to the fundamental use of mosques, in terms of contributing toward prayers and worshippers’ appreciation. This paper undertakes a comparative analysis of the acoustic quality level and the acoustical characteristics for two modern mosque buildings constructed in Erbil city. This work investigates and examines the acoustical quality and performance of these two mosques and their prayer halls through room simulation using ODEON Room Acoustics Software, to assess the degree of speech intelligibility according to acoustic criteria relative to the spatial requirements and design guidelines. The sound pressure level and other room-acoustic indicators, such as reverberation time (T30), early decay time, and speech transmission index, are tested. The outcomes demonstrate the quality of acoustics in the investigated mosques during semi-occupied and fully-occupied circumstances. The results specify that the sound quality within the both mosques is displeasing as the loudspeakers were off.

Acoustic Design of Ancient Buildings: The Odea of Pompeii and Posillipo

In this paper, a typology of a building erected in Ancient Greece and Ancient Rome is described: the Odeon. The Odeon is a covered building, but more modest in size than traditional open-air theatres without roofs. The Odeon could hold a few hundred spectators and therefore a smaller audience. The roof covering allowed the possibility of meetings even in adverse weather conditions. The etymology of the word of the Odeon (covered theatre) means the place of the ode, or of the songs. In this paper are discussed the architectonic and acoustic characteristics of the Odea of Pompeii and Posillipo. With commercial software (Odeon, Room Acoustics Software, Lyngby Denmark) we assess the acoustic characteristics of the Odea of Pompeii and Posillipo in the presence of an original roofing system and show that these buildings were well suited for music, songs and speech.

The acoustic of Roman theatres in Southern Italy and some reflections for their modern uses

Ancient Roman theatres represent a unique cultural heritage which is still used nowadays to host a variety of cultural activities and performances. Acoustic measurements show that the acoustics of these theatres does not always support the listening of music, which is common in modern performances. Although the acoustics of these theatres for modern use performances may be challenging, this cultural heritage offers a unique experience to the audience who can assist to a performance on the same seats once used by Romans. Nowadays, these unroofed theatres, whose walls behind and at the sides of the stage have rarely been restored, are often criticized for the weak sound strength. Moreover, these theatres are often exposed to urban modern background noise. The significant sound absorption due to the presence of the audience on the seating area (named cavea) and to the tapestries used in modern scenes makes challenging to support the acoustic reverberation in these theatres. In this paper, these aspects are described focusing on five ancient Roman theatres located in Southern Italy. The study reports acoustic measurements followed by virtual simulation results. As it was impossible to perform acoustic measurements with full audience occupancy, the presence of the audience was simulated using room acoustic software. The paper compares the acoustic characteristics of these five theatres considering their architectural characteristics, and discusses the role that the material used for their restoration had on their acoustics. Finally, some considerations about some reversible interventions to improve the acoustics of these ancient theatres for modern uses are reported.

A grounded theory approach to investigate the perceived soundscape of open-plan offices

This paper presents the findings of a user focused soundscape survey, that took place in a visual task based and a computational task based open-plan office spaces. Aim of this study was to conduct a grounded theory survey which captures individuals’ subjective response to the soundscape and creating a conceptual framework in the end. In order to achieve this goal, acoustical environment and sound sources were identified. In-situ measurements of sound levels (LAeq) and simulations, prepared by Odeon Room Acoustics Software 13.10 Combined, were used to explore the acoustical environment of the office spaces. Grounded Theory was used as the main research method to create a conceptual soundscape framework, and to reveal employees perception of the soundscape of their work environment. As part of grounded theory, semi-structured interviews were conducted with forty-nine employees from both types of offices. The results showed how the task at hand were affected by the sound environment and employees’ characteristics. Sound that were not expected or out of context and those that interfere with the concentration demanding tasks caused a negative interpretation of the soundscape. Due to this, employees’ adopted coping methods such as, accepting and habituating, intervening to the sound source, or putting on headphones to isolate themselves from the soundscape. It was discovered during the interviews that employees were concerned with silence as much as they were concerned with the noise. Employees expressed that the sound of keyboard and mouse means that they are working at that moment, there are other people around, and they are not working alone, or not working overtime.

Assessment of a variable acoustic system proposal in a real case

This paper is about testing a variable acoustic system proposal under development in a real case. The variable acoustic system is designed as alternating slot panels and prototyped via using Arduino and Processing. Digital interface to control the system is designed in Processing and via Arduino board digital commands are converted to physical movements. After the possibility of construction of variable perforated panel system is simply clarified, perforated panels of the system are produced via CNC routers. Panel positions are defined regarding perforation characteristics in terms of slot width and distances between slots. Changing these parameters is linked to perforation ratio of the system, while air gap and porous material behind are kept unchanged. Sound absorption capabilities of variable perforations are examined with Impedance tube measurements. Measurement results of variable slot panels, as a promising variable acoustic system, are transferred to ODEON room acoustics software, to assess the system in terms of room acoustics. The amphitheater at METU Faculty of Architecture Building, used for different functions from lectures to musical performances, is selected to demonstrate the capability of the proposed variable acoustics system to improve acoustical conditions in an amphitheater.

Evaluating the auralization of a small room in a virtual sound environment using objective room acoustic measures

To study human auditory perception in realistic environments, loudspeaker-based reproduction techniques have recently become state-of-the-art. To evaluate the accuracy of a simulation-based room auralization of a small room, objective measures, such as early-decay-time (EDT), reverberation time, clarity, interaural cross-correlation (IACC), and the speech transmission index were measured in an IEC listening room for 28 source-receiver combinations. The room was then modeled in the room acoustics software ODEON, and the same objective measures were also evaluated for the auralized version of the room. The auralizations were generated using the loudspeaker-based room auralization toolbox (LoRA; Favrot and Buchholz, 2010) and reproduced in a 64-channel loudspeaker array, set up in an anechoic chamber. Differences between the objective measures evaluated in the real and the virtual room were within about twice the just-noticeable differences for most measures, and were comparable to the median results of the study by Favrot and Buchholz, who did not consider the contribution of a real reproduction system. However, the EDT showed considerably higher errors than the other measures, even though medians were similar in the real and auralized room. This suggests that fine details in the early part of the room impulse response may be difficult to reproduce accurately.