• Journal of the Korean Institute of Educational Facilities
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• v.20 no.1
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• pp.37-44
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• 2013

The present study examines the effects of periodic type diffusers for producing the preferred acoustics for speech and determines the more successful configurations of sound-absorbing and diffusing treatments for achieving good acoustics in classrooms. The measurements were carried out in a 1/10 scale model classroom systematically adding diffusers to one or more of four surfaces of the room. A total of 13 combination of diffusers with absorptive treatments were investigated. Adding diffusers on the ceiling were more effective to increasing the early-arriving reflection energy($G_{50}$) than adding absorptive materials on the entire ceiling. The late arriving reflection energy($G_{late}$) was decreased with increasing amounts of diffusing treatments of upper front or rear wall and this resulted in achieving higher early-to-late ratios($G_{50}$). Adding diffusers on the upper front wall($AC_{100}DUFW_{26}$) achieved more uniform acoustical conditions over the receiver positions than adding diffusers on the upper rear wall($AC_{100}DUFW_{26}$). Adding diffusers on the ceiling and absorptive materials on the lower front wall($AC_{75}DC_{25}ALFW_{26}$) achieved better acoustical conditions than adding the absorptive materials on the entire ceiling and lower front wall($AC_{100}ALFW_{26}$).

• Phonetics and Speech Sciences
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• v.16 no.2
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• pp.19-27
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• 2024

The Lombard effect is an involuntary response to speakers' experiences in the presence of noise during voice communication. This study aimed to investigate the Lombard effect by comparing the acoustic features of children and adults under different listening conditions. Twelve male children (5-9 years old) and 12 young adult men (24-35 years old) were recruited to produce speech under three different listening conditions (quiet, noise-55 dB, noise-70 dB). Acoustic analyses were then carried out to characterize their acoustic features, such as F0, intensity, duration, and vowel space area, under the three listening conditions. A Lombard effect was observed in the intensity and duration for children and adults who participated in this study under adverse listening conditions. However, we did not observe a Lombard effect in the F0 and vowel space areas of either group. These findings suggest that children can adjust their speech production in challenging listening conditions as much as adults.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.63-67
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• 1999

Recently, a method of measuring impulse response is widely used for a room acoustic evaluation instead of measuring reverberation time by white noise excitation. Comparing with the traditional reverberation time measurement, this method has many advantages such as good repeatability and the ability to extract various room acoustic parameters at one measurement. In this study, the author developed a measuring system that can extract mono-aural room acoustic parameters from an impulse response measured with MLS (Maximum Length Sequence) signal excitation. These room acoustic parameters include reverberation times(EDT, RT), speech intelligibilities(C50, C80, D, U50, U80, AI) and sound strength(G). This paper introduces the configuration of the developed measuring system, test results and discussions for the measurements at several rooms.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.17-24
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• 2013

This study is aimed at finding out different types of speech characteristics categorized based on voice rehabilitation techniques used on twenty-six patients (all-male) with total or partial laryngectomees. The speech intelligibility of standard esophageal (SE), tracheoesophageal speech (TE), and electriclarynx (EL) was measured by using the CSL and eleven listeners were instructed to rate the speech on a 5-point scale. The vowel space parameters such as vowel space, VAI, FCR, and F2 ratio were measured by averaging 5 repeats of each vowel (/a/, /e/, /i/, /u/) and the results were put into the parameter formula. The results showed significant statistical differences in speech intelligibility and vowel space between SE and TE. The speech intelligibility and vowel space of TE were higher than those of SE or EL and there was a high correlation between speech intelligibility and some parameters (vowel space, VAI, F2 ratio). The results also showed that TE's speech characteristics were most similar to normal groups comparing with SE and EL, but still very deviant in laryngeal speech. This was due to insufficient airflow intake into the esophagus when producing sounds, and because articulation movement was carried out differently among groups. Therefore, these findings will contribute to establishing a baseline related to speech characteristics in voice rehabilitation for patients with alaryngeal speech.

• The Journal of the Acoustical Society of Korea
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• v.13 no.5
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• pp.51-58
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• 1994

These times many kinds of man-machine Interfaces using speech signal, speech recognizers or speech synthesizers, are proposed and utilized in practice. Especially speech synthesis system is widely used in our life. But its assessment method is still in its first stage. In this paper we propose a method to generate multi-syllable nonsense wordset for the purpose of synthetic speech assessment and applies the wordset to one commercial text-to-speech system. Some results about the experiment is suggested and it is verified that the method to generate a nonsense wordset can be used to assess the intelligibility of the synthesizer in phoneme level or in phonemic environmental level.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.147-155
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• 1998

Conventional time-scale modification methods have the problem that as the modification rate gets higher the time-scale modified speech signal becomes less intelligible, because they ignore the effect of articulation rate on speech characteristics. In this paper, we propose a variable time-scale modification method based on the knowledge that the timing information of transient portions of a speech signal plays an important role in speech perception. After identifying steady protions only. The result of subjective preference test indicates that the proposed method produces performance superior to that of the conventional SOLA method.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.660-670
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• 2021

As various people use the cafe for various purposes, it is difficult to hear conversations with the accompanying people due to the noise and background music of people around the respondents. In addition, there is a need for improvement related to the noise and sound inside the cafe, such as making it easier to hear the conversations of nearby users. 212 adult men and women participated in the questionnaire on the survey on cafe acoustics and noise conditions. As a result of the survey, about two-thirds of the respondents said that they did not prefer noisy cafes, and that the noise of cafes had a negative effect. The major source of noise in cafes is the sound of people around users, and more than 40 % of the respondents said that they could not hear well the sound of conversations with their accompanying people due to the sounds of those around them, or that they were concerned about their own conversations being transmitted to those around them. As a result of the survey on cafe sound and noise, it was found that improvements were needed to secure the voice privacy of cafe users as well as the voice intelligibility.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1977.06a
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• pp.6.1-6
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• 1977

Among the various audiometric test batteries, pure tone and speech audiometry was carried as routine. During the past 20 years, there have been works on speech word list for Korean language. As a preliminary work for standardization of Korean speech word list, the authors are intended to study on the factors of test methods with these proposal speech word lists. Now, authors has studied as followings methods and materials and the results were obtained as followings. A. Materials and Methods a. Word List 1. Paik Chun Kee (Paik) 2. Soh Jin Myoung (Soh) 3. Cynn Kyu Shik (Cynn) 4. Lee Jong Dam (Lee) 5. Hahm Tae Young (Hahm) b. Test Method 1. ascending 2. descending c. Test Material 1. live voice 2. Recorded male voice 3. Recorded female voice B. Results 1. Score of ascending method was better result than descending method. 2. Speech reception threshold and discrimination score were better in recorded female voice, live voice and recorded male voice in that order. 3. Speech reception thresholds among tested word lists were Hahm, Lee, Soh, Cynn and Paik in that order. 4. Discrimination score was highest with Cynn and Lee, Soh, Hahm, Paik in that order.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.24-33
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• 2001

this paper describes a baseline for an implementation of a corpus-based Korean TTS system. The conventional TTS systems using small-sized speech still generate machine-like synthetic speech. To overcome this problem we introduce the corpus-based TTS system which enables to generate natural synthetic speech without prosodic modifications. The corpus should be composed of a natural prosody of source speech and multiple instances of synthesis units. To make a phone level synthesis unit, we train a speech recognizer with the target speech, and then perform an automatic phoneme segmentation. We also detect the fine pitch period using Laryngo graph signals, which is used for prosodic feature extraction. For break strength allocation, 4 levels of break indices are decided as pause length and also attached to phones to reflect prosodic variations in phrase boundaries. To predict the break strength on texts, we utilize the statistical information of POS (Part-of-Speech) sequences. The best triphone sequences are selected by Viterbi search considering the minimization of accumulative Euclidean distance of concatenating distortion. To get high quality synthesis speech applicable to commercial purpose, we introduce a domain specific database. By adding domain specific database to general domain database, we can greatly improve the quality of synthetic speech on specific domain. From the subjective evaluation, the new Korean corpus-based TTS system shows better naturalness than the conventional demisyllable-based one.

• Journal of the Korean Institute of Educational Facilities
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• v.11 no.1
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• pp.5-14
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• 2004

Since 1990s in Korea, elementary school classrooms have been designed toward open education system in pursuit of variety of educational purpose. Also, the architectural designs of schools have been acomplished for individual school not based on the standard design code. The present paper aims to investigate the acoustic environment of existing classrooms and to compare the sound insulation capacity between the ordinary classrooms and the newly built classrooms for open education. The current acoustical situation of elementary classrooms was analyzed using field measurements and questionnaire survey. In order to this, Three elementary schools were selected which were built in 1978, 1996 and 2000 respectively. Room acoustical parameters including Reverberation time(RT), Definition(D50), Speech Intelligibility(RASTI), Transmission loss(TL) and STC were measured in a classroom in each elementary school classroom. Each measurement was undertaken with the windows and doors being open or closed. As the result, it was found that the transmission loss between rooms in open classrooms is, $5{\sim}6dB$ in average, inferior than the ordinary classrooms. The RASTI of 0.70 was measured in newly built classrooms which is better than old classrooms(0.70) and open classrooms(0.73). This was shown as same in the speech definition measurements. This results from the condition of sealing and airtightness of classrooms and floor materials. The results denote that open classrooms have poor acoustic condition in sound insulation and speech intelligibility.