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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of the Acoustical Society of Korea
Journal Basic Information
Journal DOI :
The Acoustical Society of Korea
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Volume & Issues
Volume 30, Issue 8 - Nov 2011
Volume 30, Issue 7 - Oct 2011
Volume 30, Issue 6 - Aug 2011
Volume 30, Issue 5 - Jul 2011
Volume 30, Issue 4 - May 2011
Volume 30, Issue 3 - Apr 2011
Volume 30, Issue 2 - Feb 2011
Volume 30, Issue 1 - Jan 2011
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Efficient Individualization Method of HRTFs Using Critical-band Based Spectral Cue Control
Hur, Yoo-Mi ; Park, Young-Cheol ; Lee, Seok-Pil ; Youn, Dae-Hee ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 167~180
DOI : 10.7776/ASK.2011.30.4.167
Recently, 3-D audio technologies are commonly implemented through headphones. A major problem of the headphone-based 3-D audio is in-the-head localization, which occurs due to the inaccurate Head-Related Transfer Function (HRTF). Since the individual measurements of HRTFs are impractical, there have been several researches for HRTF customization. In this paper, an efficient method of customizing HRTFs for the sound externalization is proposed. Firstly, it is determined which part will be customized in HRTF through psychoacoustical experiments. Then, the method controlling spectral notches and envelopes to provide individual localization cues are described. Since the proposed method is based on a critical-band rate, the structure is much simpler than that of previous studies, but still effective. The performance was evaluated through a series of subjective tests, and the results confirmed that the customized HRTF using proposed method could replace the measured individual HRTF successfully.
Research for Characteristics of Sound Localization at Monaural System Using Acoustic Energy
Koo, Kyo-Sik ; Cha, Hyung-Tai ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 181~189
DOI : 10.7776/ASK.2011.30.4.181
According to developments of digital signal processing, 3D sound come into focus on multimedia systems. Many studies on 3d sound have proposed lots of clues to create realistic sounds. But these clues are only focused on binaural systems which two ears are normal. If we make the 3d sound using those clues at monaural systems, the performance goes down dramatically. In order to use the clues for monaural systems, we have studies algorithms such as duplex theory. In duplex theory, the sounds that we listen are affected by human`s body, pinna and shoulder. So, we can enhance sound localization performances using its characteristics. In this paper, we propose a new method to use psychoacoustic theory that creates realistic 3D audio at monaural systems. To improve 3d sound, we calculate the excitation energy rates of each symmetric HRTF and extract the weights in each bark range. Finally, they are applied to emphasize the characteristics related to each direction. Informal listening tests show that the proposed method improves sound localization performances much better than the conventional methods.
Developing a Low Power BWE Technique Based on the AMR Coder
Koo, Bon-Kang ; Park, Hee-Wan ; Ju, Yeon-Jae ; Kang, Sang-Won ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 190~196
DOI : 10.7776/ASK.2011.30.4.190
Bandwidth extension is a technique to improve speech quality and intelligibility, extending from 300-3400 Hz narrowband speech to 50-7000 Hz wideband speech. This paper designs an artificial bandwidth extension (ABE) module embedded in the AMR (adaptive multi-rate) decoder, reducing LPC/LSP analysis and algorithm delay of the ABE module. We also introduce a fast search codebook mapping method for ABE, and design a low power BWE technique based on the AMR decoder. The proposed ABE method reduces the computational complexity and the algorithm delay, respectively, by 28 % and 20 msec, compared to the traditional DTE (decode then extend) method. We also introduce a weighted classified codebook mapping method for constructing the spectral envelope of the wideband speech signal.
Amplitude Panning Algorithm for Virtual Sound Source Rendering in the Multichannel Loudspeaker System
Jeon, Se-Woon ; Park, Young-Cheol ; Lee, Seok-Pil ; Youn, Dae-Hee ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 197~206
DOI : 10.7776/ASK.2011.30.4.197
In this paper, we proposes the virtual sound source panning algorithm in the multichannel system. Recently, High-definition (HD) and Ultrahigh-definition (UHD) video formats are accepted for the multimedia applications and they provide the high-quality resolution pixels and the wider view angle. The audio format also needs to generate the wider sound field and more immersive sound effects. However, the conventional stereo system cannot satisfy the desired sound quality in the latest multimedia system. Therefore, the various multichannel systems that can make more improved sound field generation are proposed. In the mutichannel system, the conventional panning algorithms have acoustic problems about directivity and timbre of the virtual sound source. To solve these problems in the arbitrary positioned multichannel loudspeaker system, we proposed the virtual sound source panning algorithm using multiple vectors base nonnegative amplitude panning gains. The proposed algorithm can be easily controlled by the gain control function to generate an accurate localization of the virtual sound source and also it is available for the both symmetric and asymmetric loudspeakers format. Its performance of sound localization is evaluated by subjective tests comparing with conventional amplitude panning algorithms, e.g. VBAP and MDAP, in the symmetric and asymmetric formats.
A Technique for Preventing Noise Induced Hearing Loss Due to Mobile Phone Use Under Noisy Environment
Park, Hyung-Woo ; Lee, Sung-Tae ; Bae, Myung-Jin ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 207~214
DOI : 10.7776/ASK.2011.30.4.207
Human auditory acuity decreases naturally due to aging. But recently cases of impaired hearing at a young age are increasing greatly. The biggest reason for such an increase of population with impaired hearing is popularization of various kinds of portable multimedia appliances. Many studies on impaired hearing due to noises caused by the earphone and headphone are being made, but there are few studies on noise-impaired hearing caused directly by mobile phone communication. Based on a precedent inquiry, this study proposes a technique for preventing noise-impaired hearing applying to an active noise reduction technique onto bone conduction speaker. This technique is a method for reducing noises by antiphase oscillation through bone conduction speaker with ambient noises. If the proposed system is applied, the noise level that is actually introduced to audition decreases by more than 12 dB, and such a decreased amount of sound volume fundamentally prevents the factors of noise-caused hearing difficulty due to mobile phone communication. Sensibility test results showed that adequate communication was possible even in such a situation where communication volume was decreased like this.
Fabrication and Evaluation of a VHF Focusing Ultrasonic Transducer Made of PVDF Piezoelectric Film
Yoon, Ju-Ho ; Oh, Jung-Hwan ; Kim, Jung-Soon ; Kim, Moo-Joon ; Ha, Kang-Lyeol ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 215~222
DOI : 10.7776/ASK.2011.30.4.215
In order to obtain high resolution images, a focusing ultrasonic transducer operated in very high frequency (VHF) range was fabricated and its characteristics were evaluated. A 9-
thick PVDF film with only one metalized surface for electric ground was adhered to a CCP (Copper-clad polyimide) film by using epoxy. It was pressed by a metal ball to form a concave surface and its rear side was filled with the epoxy. The radius of curvature and the f-number of the fabricated transducer are 7.5 mm and 1.7, respectively. The pulse-echo measurement results from a target located at the focal point showed that the frequency bandwidth was 35.0 MHz and the insertion loss near the peak frequency of approximately 40 MHz was about 60 dB. Those values agreed well with the simulation results by the KLM equivalent circuit analysis including the effect of the epoxy bonding layer. When the image of thin copper lines by the 35 MHz transducer of the UBM (Ultrasonic Backscattering Microscope) system was compared with the image by the transducer fabricated in this study, the fabricated transducer was observed that the axial resolution was improved although the lateral resolution was degraded.
Resonance Condition of the Resonance Cavity and Air Gap in the Sacred Bell of the Great King Seongdeok
Kim, Seock-Hyun ; Jeong, Won-Tae ; Kang, Yun-June ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 223~230
DOI : 10.7776/ASK.2011.30.4.223
Korean bell is hung with some air gap between the bell bottom and the ground. In addition, it has a peculiar acoustic element, so called resonance cavity below the bell. A proper design of the air gap and cavity size dramatically amplifies the bell sound by resonance effect. Bell interior cavity, air gap and resonance cavity consist of an acoustic cavity system. When the acoustic cavity frequency coincides with the natural frequency of the bell body, the frequency component is significantly amplified. On the Sacred Bell of the Great King Seongdeok, this study proposes a resonance condition of the cavity system considering air gap effect for the first time. With the exact dimension of the bell, boundary element analysis is performed using SYSNOISE. Finally, this study reveals how the temperature in season influences the resonance condition and proposes a concept of variable type resonance cavity. By using the variable type resonance cavity, the cavity size is controlled on site and exact resonance is available regardless of temperature difference in season.
Diagnosis and Evaluation of Humanities Therapy: The Phonetic Analysis of Speech Rates and Fundamental Frequency According to Preferred Sensation Type
Lee, Chan-Jong ; Heo, Yun-Ju ;
The Journal of the Acoustical Society of Korea, volume 30, issue 4, 2011, Pages 231~237
DOI : 10.7776/ASK.2011.30.4.231
The purpose of this study is to examine the correlation between the preferred sensation type and speech sounds, especially on
and the speech rates. Data for the sensation types and speech sounds were collected from 36 undergraduate and graduate students (17 male, 19 female). Subjects were asked to read a given text (400 syllables), describe a drawing, and give answers to some questions. We measured speakers`
and speech rates. The results show that type V (Visual) has the correlation with the speech rates when type D (Digital) was ruled out, and type A (Auditory) has the correlation with the speech rates when type D was included. Furthermore, the analysis of the mean values of V, A, K (Visual, Auditory, Kinethetic) indicates that type V is characterized with faster speech rates and higher
in all parts except for interview and the same is true for that of V, A, K, D (Visual, Auditory, Kinethetic, Digital) in all parts. In conclusion, this study proved that the preferred sensation type has the correlation with
and speech rates. Based on the results of this study,
and speech rates can be used to analyze the sensation types for individualized education as well as consultation. In addition, this study has great significance in that it lays a foundation for the study on the correlation between a preferred sensation type and speech sounds.