تحلیل تاثیر تغییرات حجمی بر رفتار آکوستیکی در مساجد؛ مطالعه موردی: مساجد تاریخی تبریز (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
شنوایی در انسان حسی است که در انتخاب ورودی ها نقشی ندارد و ناخودآگاه در برابر صداها قرار می گیرد. محیط زندگی انسان، سرشار از این اصوات است و منابع مختلفی به ازدیاد آن کمک می نمایند که در هر محیطی بسته به موقعیت انسان، تعریف حداکثری برای میزان بار وارده صوتی به گوش انسان تعریف می شود. مساجد به عنوان عملکردی خاص در زمینه آکوستیک نیازمند رفتارهای چندگانه در این حوزه اند. مسجد ایده آلِ آکوستیکی بایستی بتواند در عین این که به فضاهای خلوت و تمرکز فردی اهمیت می دهد، در پخش مناسب صدا به منظور کاربردهای جمعی نیز موفق عمل نماید. به نظر می رسد رفتار کلی صوتی در مساجد با فرم و ساختار سنتی در احجام کمتر همگن تر بوده، تراز فشار صدا (Sound Pressure Level: SPL) را در کلیت فضا بالاتر نشان دهد و در نمونه های حجیم تر مکان های متعدد با فشار بالای صدا اما ناهمگن بوجود آید. به منظور واکاوی فرضیه ی مذکور، طرح مطالعاتی پیش رو، در دو فاز مطالعاتی و میدانی انجام یافته و تحلیل رفتار صوتی دغدغه اصلی پژوهش است تا بتوان در گونه های مختلف حجمی تفاوت های آکوستیکی را با تکیه بر ابزارهای سنجش بروز که ارائه دهنده نتایج کارآمدتری نیز خواهد بود؛ بررسی و تحلیل نمود. نتایج پژوهش نشان می دهد افزایش حجم در ساختار یکسان نمونه ها، موجب کاهش فشار صدا در بنا می شود و در عین حال زمان واخنش افزایش می یابد. این مقوله به فرکانس وابستگی مستقیم دارد و در فرکانس های پایین تر، افزایش حجم تاثیر کمتری در تراز فشار صدای فضا دارد.Analysis of the Impact of Volume Changes on Acoustic Behavior in Mosques; Case Study: the Historic Mosques of Tabriz
Extended Abstract Background and Objectives: Hearing in humans is a sense which has no role in selecting entries and responds unconsciously to various sounds. The environment in which humans live is overfilled with such sounds and vis saturated with different types of sounds from a variety of sources. Depending on the location of the human, the maximum amount of sound exposure that the ear can tolerate is determined. Architecture limits and frames sound. This causes the sound to behave differently indoors than outdoors. The type of difference is sometimes desirable and sometimes undesirable, and this is due to different architectures. There are many effective components in the formation of architecture and the physical structure of a place. However, early studies in Acoustics for architecture, exemplified by Sabine's formula, placed emphasis on the size, materials, and surface area of space as the most important factors in shaping its acoustics. As mosques are of a particular function in terms of acoustics, they require multiple behaviors in this field. An acoustically ideal mosque should not only provide quiet spaces for individual concentration, but also distribute sound effectively for collective use. According to Sabin's formula, this can be achieved through careful consideration of the volume, materials, and surface area of the space. Methods: The purpose of this study was to investigate how changes in volume affect the acoustic behavior of mosques. To achieve this, the study aimed to maintain consistent parameters affecting sound measurements to analyze the impact of volume variations on the acoustic behavior of mosques. Findings suggest that traditional mosques with smaller volumes generally have more homogeneous sound behavior and exhibit higher sound pressure levels throughout the space. In contrast, larger mosques may have areas with high sound pressure levels but inconsistent sound behavior. The study was conducted in two phases - a theoretical phase and a field study - focusing on analyzing the acoustic behavior of mosques using advanced tools to obtain accurate results. The main objective of the research was to differentiate between acoustics in different volumetric types and identify effective techniques. In order to measure the Reverberation time, the 2260 device of B&K Denmark has been used, and several points have been measured in mosques depending on the size of the plan surface. The SINUS Acoustic Camera was utilized for imaging purposes and was operated in two positions. During the first stage, the samples' overall noise level was recorded. In the second position, the sound source was utilized. In all instances, the position of the source in the Mihrab was taken into account. This was done to simulate the preacher's typical placement in the Mihrab. The selected frequency range is up to 10 kHz. Findings: The findings indicate that all samples had a consistent sound distribution of 94 decibels. However, the largest volume exhibited the lowest sound pressure level, while the smaller volumes had higher sound pressure levels in proportion to their size. This shows that the effect of loud noises in space is much less felt with increasing volume. This acoustic event intensifies with increasing frequency and the effect of volume is less at low frequencies. On the other hand, increasing the volume increases the reverberation time, and this change, in contrast to the SPL, is greater at lower frequencies. In other words, the volume at lower frequencies is an effective factor in changes in the reverberation time and does not play a significant role in the reverberation time of space at high frequencies. Conclusion: The results show that increasing the volume in the same structure of the samples reduces the sound pressure level in the building and, at the same time, increases the reverberation time. This is directly dependent on the frequency, and at lower frequencies, increasing the volume has less effect on the sound pressure level. In the reverberation time factor, the frequency behavior is inverse and the volume will be less effective at higher frequencies, which proves the acoustic balance in the samples. The three factors of volume, reverberation time, and sound pressure level vary in relation to the frequency range. The relationship between volume, reverberation time, and sound pressure level also varies depending on the frequency spectrum. This finding will be effective in designing mosques with a similar structure because the reverberation time and the desired sound pressure level can be predicted depending on the desired volume. On the other hand, since a standard amount is defined for reverberation time in mosques and other settings, the volume of the space can be designed, and the sound pressure level can be adjusted to achieve the desired Reverberation time.
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