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Araştırma makalesi

AL-BAYYAR ZINAH, KITAPCI KIVANC (2022).  Effects of reverberation time and sound source composition on sense of place constructs.  Applied Acoustics, 185.

This study investigates the influence of reverberation time and sound source composition on the sense of place. The experiments were conducted in the private lecturer offices located in the Faculty of Architecture, Çankaya University. The sense of place of 15 participants were tested in the original offices of each participant and eight additional acoustic auralisations, in which reverberation times and sound source compositions were modified. The analysis of the results revealed that there is a direct influence of reverberation time and sound source composition on the sense of place. It was observed that longer reverberation times partially enhanced the sense of place. Additionally, the sound source composition influenced the relation towards the place, and certain sound signals diminished the sense of place in the private offices. Furthermore, this study used a psychophysical scaling method (Absolute Magnitude Estimation scale [AME]) which indicated its validity and importance in investigating the effect of physical stimuli on the sense of place. The AME revealed the sense of place by directing the influence towards the place construct indicators rather than investigating the general relation towards the place. It was concluded that reverberation time and sound source compositions could enhance and/or diminish sense of place; hence, RT and sound source compositions can affect interpretation of and behaviour towards a given place.

Araştırma makalesi

KITAPCI KIVANC, CELIK BASOK GULSAH (2021).  The acoustic characterization of worship ambiance and speech intelligibility in wooden hypostyle structures: The case of the Aslanhane Mosque.  Acoustics Australia, 49, 425-440.

The challenge in the acoustics design of the traditional mosque is twofold. First, the interior atmosphere of the space should create a sacred feeling on the users’ holistic and phenomenological spatial perception, which is generally recognized as a direct effect of increased reverberation time (T30) and low clarity (C80). Second, the speech should be adequately intelligible, which requires a low T30 and high speech clarity, contradicting the initial concern of the sacred atmosphere. We hypothesize that in Islamic architecture, wooden hypostyle mosques may comply better with the reverberation time requirements of speech intelligibility, while maintaining the sacred feeling, due to their comparatively absorptive surface finishing materials and structural elements. The Aslanhane Mosque is a unique sacred structure within its era of construction, well-known with its wooden columns and ceiling. It is an important case for room acoustics analysis of such holy spaces. This study aimed to analyze the room acoustic measurement results of the Aslanhane Mosque, evaluating the intelligibility of speech and interpreting the sacred feeling created by reverberance, envelopment, and spaciousness, which are all crucial in such holy structures. It is revealed that although The Aslanhane Mosque’s subjective rating for speech intelligibility is ‘good’, the overall low volume of the mosque and the lack of surface reflections decrease the sacred sensation. Additionally, the intelligibility of speech is vulnerable to obstacles within the line of sight, such as load-bearing columns. Lastly, it was observed that the increase in T30 at low frequencies improved the sacred sensation, envelopment, and spaciousness, without any profound negative impact on the intelligibility of speech.

Araştırma makalesi

KITAPCI KIVANC, AKBAY SAADET (2021).  Audio-Visual Interactions and the Influence of colour on noise annoyance evaluations.  Acoustics Australia, 49(2), 293-304.

This study aims to examine the influence of colour exposure on noise annoyance. Previous studies in the literature have focused mostly on the effects of colour exposure on loudness judgements; however, due to the cognitive nature of multisensory perception, the influence of colour on noise annoyance also needs to be investigated. Our experiments were designed to administer non-information-carrying sound signals (i.e. white noise) and visual stimuli (i.e. abstract colour samples) and to limit visual and auditory contextual information. Participant were asked to evaluate noise annoyance on a 11-point International Commission on the Biological Effects of Noise (ICBEN) scale. The experiments were conducted in the form of audio-visual tests. During these tests, random combinations of three white noise sound samples with sound pressure levels of 66 dB(A) (-4 dB[A] acoustic condition), 70 dB(A) (0 dB[A] acoustic condition) and 74 dB(A) (+4 dB[A] acoustic condition), and six visual stimuli, including the elementary colours of Natural Colour System (NCS) – yellow (Y), red (R), blue (B), and green (G), white and black (S) – were presented to a total of 42 participants. The black colour sample was used to measure the audio-only control condition for the three white noise sound samples. The results of the study reveal that the effects of sound, the effects of colour and the interaction effects of colour and sound on perceived noise annoyance were statistically significant. The effects of colour on the loudness evaluations of the previous studies and the effects of colour on noise annoyance evaluations presented in this study show very similar and concordant results, indicating that the effects of colour on noise annoyance depended on the sound pressure level (SPL). The results indicate that the hue contrasts of red-green, red-blue and yellow-blue and the lightness contrast of yellow-blue influenced perceived noise annoyance when the SPL was low or high. Within the contrast pairs, red and yellow are perceived to be annoying, whereas blue and green are perceived to be non-annoying. 

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KITAPCI KIVANC, GALBRUN LAURENT (2019).  Perceptual analysis of the speech intelligibility and soundscape of multilingual environments.  Applied Acoustics, 151, 124-136.

This paper examines the perceived speech intelligibility of English, Polish, Arabic, and Mandarin and, more generally, the soundscape associated to multilingual environments. Listening tests were used to evaluate three acoustic environments (an airport, a hospital, and a café) under three room acoustic conditions defined by a different speech transmission index (STI) (STI = 0.4, 0.5 and 0.6). In the tests, participants rated eleven semantic attributes representative of speech perception and the overall soundscape (speech intelligibility, speech level, speech pleasantness, noisiness, annoyance, relaxation, comfort, environment pleasantness, eventfulness, excitement, and familiarity). Results obtained indicate that inter-language comparisons based on perceived speech intelligibility are different from those obtained from objective speech intelligibility tests. Noticeably, English participants were found to be most sensitive to changes in room acoustic conditions and to meaningful and distractive noise sources, whilst Arab participants were least sensitive to changes in room acoustic conditions and more tolerant to noise. Perceived speech intelligibility correlated significantly with non-acoustical factors (speech pleasantness, comfort and environment pleasantness), and ‘emotional factors’ (annoyance, relaxation, comfort and environment pleasantness) explained a large portion of the variance in soundscape assessment. Results also showed that language affected the perceived speech intelligibility marginally (p = 0.051) and noisiness significantly (p = 0.047), the latter being the best indicator of cultural variations amongst the attributes tested. Overall, the study shows that designing for speech intelligibility cannot be solely based on room acoustic parameters, especially in the case of multi-lingual environments.

Araştırma makalesi

KITAPCI KIVANC, YILMAZER SEMIHA (2018). Acoustics and speech privacy in open-plan offices: A case study on computer-based task performance. GRID – Architecture Planning and Design Journal, 1, 1-23.

The aim of this study is to find out the effects of speech and speech intelligibility on computer-based task performance in open-plan offices. The research was conducted in a real open-plan office environment to include the open-office experience of subjects to the analysis. STM Bilkent Office was selected as the case, and 40 available open-office occupants were participated to the study. The experiment consists of two main phases. In the first phase, acoustical simulation of the site was done, to derive distribution graphs for speech related room acoustics parameters. In the second phase, occupants’ computerbased task performances were tested under three different sound environments, which are continuous noise, speech and masked speech. According to statistical analysis of the performance test, and the acoustical properties of the case STM, suggestions for renovation were discussed. It was found that effects of intelligible speech on occupants’ task performance are only psychological, because it is significant that there is no difference between results of performance test. However, all of the occupants respond to the questionnaires that speech sound environment was the most distracting one. Proposal for renovation was given to minimize the effects of intelligible speech on occupants for preventing the long-term effects on occupants’ health. 

Araştırma makalesi

GALBRUN LAURENT, KITAPCI KIVANC (2016).  Speech intelligibility of English, Polish, Arabic and Mandarin under different room acoustic conditions.  Applied Acoustics, 114, 79-91.

This paper examines the impact of room acoustic conditions on the speech intelligibility of four languages (English, Polish, Arabic and Mandarin). Listening test scores (diagnostic rhyme tests, phonemically balanced word tests and phonemically balanced sentence tests) of the four languages were compared under four room acoustic conditions defined by their speech transmission index (STI = 0.2, 0.4, 0.6 and 0.8). The results obtained indicated that there was a statistically significant difference between the word intelligibility scores of languages under all room acoustic conditions, apart from the STI = 0.8 condition. English was the most intelligible language under all conditions, and differences with other languages were larger when conditions were poor (maximum difference of 29% at STI = 0.2, 33% at STI = 0.4 and 14% at STI = 0.6). Results also showed that Arabic and Polish were particularly sensitive to background noise, and that Mandarin was significantly more intelligible than those languages at STI = 0.4. Consonant-to-vowel ratios and languages’ distinctive features and acoustical properties explained some of the scores obtained. Sentence intelligibility scores confirmed variations between languages, but these variations were statistically significant only at the STI = 0.4 condition (sentence tests being less sensitive to very good and very poor room acoustic conditions). Overall, the results indicate that large variations between the speech intelligibility of different languages can occur, especially for spaces that are expected to be challenging in terms of room acoustic conditions. Recommendations solely based on room acoustic parameters (e.g. STI) might then prove to be insufficient for designing a multilingual environment.