An Optimum Reverberation Time for Mosques in Bangladesh

Abstract

For a mosque in Bangladesh, the acoustical requirements in terms of intelligibility and liveliness are dissimilar for the types of sounds - recitation from the Holy Koran and speech on religious subjects. To attain an overall satisfactory acoustical performance, it is significant to find an optimum Reverberation Time (RT), which is one of the important factors affecting intelligibility and liveliness. Experiment is conducted to find the effect of RT by making it a variable, while keeping other factors as non-variable and fulfilling ideal conditions for maximum intelligibility. Preferences are judged on pairs of sound clips of recitation and speech, for both intelligibility and liveliness, on a 5-point scale and findings are analysed thorough the statistical method of paired comparison. Considering preferences of all aspects the optimum RT is proposed as 0.9 s for an overall balanced acoustical performance for both recitation and speech for a mosque in Bangladesh. Keywords: Intelligibility, Liveliness, Mosque, Recitation, Reverberation time, Speech. DOI: 10.3329/bjsir.v44i2.3667 Bangladesh J. Sci. Ind. Res. 44(2), 163-170, 2009

An Assessment of Acoustic Quality in Mosque Case Study: Masjid At-Tarbiyah UIN Malang

“…This study uses modeling and simulation using the Ecotect v.2011 program to determine the value of acoustic quality in the research object to calculate the reverberation time (RT). RT is used to measure room acoustics' quality based on reverberation time standards [15] for the talking room, which will affect all interior elements of the space, such as walls, ceilings, and openings.…”

“…These reflective materials include glass materials that tend to be closed, plaster brick wall materials, and ceiling materials made of reinforced concrete and gypsum. Besides, the shape of the dome mosque roof also contributes to reflected sounds in the mosque [15].…”

The Optimal Reverberation for Masjids

“…Performing recitation includes text priority, a pause between phrases, and not playing purposely with the text for melodic reasons, this makes it differ from the music performance that is subjected to the variants and versions [40]. Because the performance is melodic and because we prefer a longer reverberation for music than for speech [41], recitation needs a longer reverberation time for liveliness and to add the depth required for such type of spiritual performance [21,36]. There are two common styles (methods) in which the Qur'an can be recited: the very slow style (known as the Mujawwad, see Appendix A) or the slow style (known as the Moratal, see Appendix A) that is usually utilized during prayer either in a group or as individuals [21].…”

“…Under the subjective category, many researchers aim to identify the acoustic requirements and demands of either the worshippers (the audience) or the Imam (the sole performer, see Appendix A). For the former, Najmul Imam et al studied the acoustic demands of twelve Bangladeshi male worshippers (non-Arabic speakers) who are almost in the same age (32 years old on average) [36]. For the latter, Elkhateeb recently published a detailed study of the acoustic demands of imams with Arabic mother tongue [37].…”

“…For the latter, Elkhateeb recently published a detailed study of the acoustic demands of imams with Arabic mother tongue [37]. To the best of the authors' knowledge, the works of Najmul Imam [36,38] and the work of Elkhateeb are, perhaps, the only studies in this area. Still, the acoustic demands of Arabic-speaking Muslim worshippers of different genders and ages have not been studied yet.…”