Acoustic analysis of selected sacred buildings in Szczecin

The aim of this study was to assess acoustically selected sacred buildings located in Szczecin. The research part contains the research methodology and the results obtained. The research was carried out using two methods. The first one is the integrated impulse response method, where, using a bursting balloon, the time of sound pressure drop was measured at selected points of the object. In the interrupted noise method, the sound pressure drop was measured after the noise generated by the omnidirectional loudspeaker had ceased. Reverberation time was calculated for the results obtained, which is the main and basic parameter determining the interior acoustics. On the basis of the above-mentioned measurements, the reverberation indicators for the temples were also calculated. When analyzing the components of the reverberation indicator, it was noticed that poor acoustics in the sanctuary concerns speech, while interior acoustics is good for the reception of organ music. In the analyzed church, the reception of liturgical music is also better than the reception of speech, but the differences between these values are small.

Acoustic quality assessment in a classroom through simulations and measurements

The acoustic quality in a classroom directly impacts the educational relationship between the student and the teacher, reducing speech intelligibility. In addition, inadequate acoustic comfort burdens the vocal health of teachers. This study evaluated a classroom at the Federal University of Paraná, Campus Centro Politécnico, to verify its acoustic quality. The measurements of the acoustics descriptors: Reverberation Time (RT), Definition (D50), Central Time (Ts), Early Decay Time (EDT) were performed according to the ISO 3382-2 standard, concerning Noise Curves (NC) and Background Noise (BGN) these were evaluated by the NBR 10152 and S12.2 standards. The Speech Transmission Index (STI) was measured according to IEC 60268-16 and evaluated according to ISO 9921. The useful-detrimental ratio (U50) and the other descriptors were simulated in the ODEON software version 11. Thus, the results showed that the evaluated room did not meet the minimum requirements in terms of acoustic quality, for the descriptors RT, STI, Ts, D50, RF, and NC. Simultaneously, the RT and STI were also outside the limits established by the German and Finnish standards. Therefore, it is concluded that the evaluated classroom did not reach the minimum acoustic quality requirements.

Subjective Experience of Speech Depending on the Acoustic Treatment in an Ordinary Room

In environments such as classrooms and offices, complex tasks are performed. A satisfactory acoustic environment is critical for the performance of such tasks. To ensure a good acoustic environment, the right acoustic treatment must be used. The relation between different room acoustic treatments and how they affect speech perception in these types of rooms is not yet fully understood. In this study, speech perception was evaluated for three different configurations using absorbers and diffusers. Twenty-nine participants reported on their subjective experience of speech in respect of different configurations in different positions in a room. They judged sound quality and attributes related to speech perception. In addition, the jury members ranked the different acoustic environments. The subjective experience was related to the different room acoustic treatments and the room acoustic parameters of speech clarity, reverberation time and sound strength. It was found that people, on average, rated treatments with a high degree of absorption as best. This configuration had the highest speech clarity value and lowest values for reverberation time and sound strength. The perceived sound quality could be correlated to speech clarity, while attributes related to speech perception had the strongest association with reverberation time.

Acoustics of a School Building Made in Wooden Technology on the Example of Building from the Second Half of the 19th Century

The Władysław Matlakowski School in Zakopane was established in 1877. After the war damage, during the Communist rule in Poland the school was rebuilt and renovated. As a result, the original character of the classrooms was distorted. Fiberboards used for interior finishing changed the acoustic climate of the rooms. The reverberation time of the tested rooms considerably exceeds 2 seconds for low frequencies and is below 2 seconds for medium frequencies. Thus, the reverberation conditions do not differ from typical school classrooms in Poland. The tests of reverberation conditions were supplemented by the measurements of acoustic insulation of partitions separating the chool classrooms from each other and from the corridor. The studies allow to infer that the noise possibly comes from the corridors or adjacent rooms.

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

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.

Initial Study on the Reverberation Time Standard for the Korean Middle and High School Classrooms Using Speech Intelligibility Tests

The most important function of the classroom is to transmit educational information from teachers to students more accurately and clearly. The acoustical environment of the classroom thus has an important effect on the improvement of students’ learning ability. To provide an appropriate acoustical environment for learning to students, it is necessary to create an acoustical performance standard for classrooms and a guideline for designing classrooms. However, in Korea, there is not an acoustical standard for classrooms; thus, it is difficult to control and manage appropriate acoustical performance when designing and building classrooms. The present study aims to suggest acoustic performance standards for classrooms that are suitable for the Korean language. In order to perform this study, standard classrooms were created by standardizing architectural dimensions of 17 middle and high school classrooms in Cheong-ju. Speech intelligibility tests were conducted using three different languages including Korean, English, and Chinese. Twenty native speakers for each language were used as subjects for the speech intelligibility tests. Finally, auralized sound sources were created with five different conditions of reverberation time (0.47 s~1.22 s) by changing indoor sound absorption of a real classroom. Listening tests were undertaken by 52 Korean adults with normal hearing, using the auralized sound source. The results proved that the most appropriate reverberation time for learning was above 0.76 s. Based on the research findings, the ideal acoustical performance standard for classrooms in Korea is as follows: background noise is below 35 dBA, and reverberation time is below 0.80 s. It is also necessary that indoor sound absorption should be above 20% without sound absorption on side walls in order to satisfy with the acoustical performance standard.