• The Journal of the Acoustical Society of Korea
• /
• v.43 no.1
• /
• pp.39-48
• /
• 2024

A car horn serves a crucial safety role as a means of communication between drivers and a part that alerts pedestrians in advance. While previous studies have utilized finite element method and electric circuit model to simulate and analyze characteristics of the car horns, there remains a lack of research on design methods of a trumpet horn. This paper presents a design approach that predicts the operating frequency based on the acoustic reactance at the throat of the horn, once the vibrating part is determined. We deal with a horn combining both an exponential horn and a waveguide in the acoustic section, and confirm that the acoustic reactance at the horn throat measured by impedance tube experiment agrees well compared with the numerical result obtained using the finite element method. The resonance frequency of the car horn is predicted using the COMSOL Multiphysics finite element numerical analysis model, and the proposed design method is validated by measuring the operating frequency of the designed horn in a sound pressure experiment. As a result, the resonance measured in a semi-anechoic chamber environment by applying a DC voltage of 12 [V] excluding the holder occurs accurately within a few [Hz] of the design operating frequency. This paper discuss the design method of a trumpet horn from the perspective of the horn's acoustic reactance, and is expected to be useful for designing horn systems.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.6
• /
• pp.57-65
• /
• 2001

In this paper, we designed the acoustic horn for magnetostrictive ultrasonic transducers in a theoretical manner, and validity of the analysis was verified through comparison with the results of finite element analysis. Results of the two analysis methods showed good agreement with each other. The theoretical method can fairly quickly determine the horn length that satisfies given frequency specification, but also has the drawback that it is applicable only to the frequency range over the cut-off frequency. According to the results, the catenoidal horn can provide larger amplification than the exponential horn. It was also found that it is more desirable for the region having the catenoidal curvature to be as short as possible to achieve larger amplification of the transducer deformation. Based on the analysis results, a magneto-strictive transducer sample was fabricated and its performance was evaluated experimentally. The transducer has the resonance frequency of 19.3 ㎑ as well as the maximum SPL of 199 dB, and shows the omni-directional radiation pattern.

• The Journal of the Acoustical Society of Korea
• /
• v.26 no.7
• /
• pp.323-327
• /
• 2007

In this paper, objectively quantified consonance of complex sound is proposed as a new psychoacoustical parameter. Proposing algorithm quantifies consonance of complex sound after applying psycho acoustical models which are parts of human perception such as masking effect, equal loudness contour, and critical band. To verify proposing algorithm, experiments with 10 car horn signals which have different complex sound were performed. The experiments show cross correlation of 0.95 between objectively quantified consonance by proposing algorithm and subjectively assessed consonance by listening tests. Considering the fact that there are few psychoacoustical parameter except Zwicker parameter, proposing algorithm will help to quantify psychoacoustical effect of complex sounds objectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.55-56
• /
• 2014

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.6 s.111
• /
• pp.565-573
• /
• 2006

Acoustic analysis of a moving sound source required that the measured sound signals be do-Dopplerized and restored as of the original emission signals. The purpose of this research is development of beamforming technique can be applied to the rotor noise source identification. For the do-Dopplerization and reconstruction of emitted sound wave, Forward Propagation Method is applied to the time domain beamforming technique. And validation test were performed using rotating sound source constructed by bended pipe and horn driver. In the validation test using sinusoidal sound wave, sufficient performance of signal processing can be seen, and the effect of measuring duration for accuracy was compared. In the prop-rotor measurements, the acoustic source locations were successfully verified in varying positions for different frequencies and collective pitch angle, in hover condition.

• Journal of KSNVE
• /
• v.8 no.4
• /
• pp.706-714
• /
• 1998

The purpose of this study is to analyse the main factors and attributes of psychological evaluation to noise. For this purpose, a psycho-acustic experiment was conducted by using the method of rating scale. 52 subjects were participated in the experiment, 20 stimuli were presented to subjects in random order with 23 adjectives. As a result of factor analysis, it was found that the primary factors for evaluating the quality of noise subjectively are four factors of unpleasantness, intensity, irregularity, and sharpness. And, as a result of MDPREF(multi-dimensional analysis of preference data), it was found that the noise sources including the factors of unpleasantness, intensity, and irregularity are related to the sounds of hammering in construction field, car horn, road traffic, idling of car, and printing by computer printer, and the factor of sharpness are the sounds of car siren, claps of thunder, car horn, and snowstorm etc.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.7
• /
• pp.1263-1269
• /
• 2016

Hearing impaired persons are exposed to the danger since they can't be aware of many dangerous situations like fire alarms, car hones and so on. Therefore they need haptic or visual informations when they meet dangerous situations. In this paper, we design a dangerous sound detection engine for hearing impaired. We consider four dangerous indoor situations such as a boiled sound of kettle, a fire alarm, a door bell and a phone ringing. For outdoor, two dangerous situations such as a car horn and a siren of emergency vehicle are considered. For a test, 6 data sets are collected from those six situations. we extract LPC, LPCC and MFCC as feature vectors from the collected data and compare the vectors for feasibility. Finally we design a matching engine using an artificial neural network and perform classification tests. We perform classification tests for 3 times considering the use outdoors and indoors. The test result shows the feasibility for the dangerous sound detection.

• Journal of Korea Multimedia Society
• /
• v.11 no.4
• /
• pp.471-480
• /
• 2008

The deaf can not recognize useful sound informations such as alarm, doorbell, siren, car horn, and phone ring etc., because they have the hearing impairment. To solve this problems, portable hearing assistive devices which have suitable environment sound recognition methods are needed. In this paper, the DTW algorithm for sound recognition system with new active slope weighting constraint method was proposed. The environment sound recognition methods consist of three processes. First process is extraction of start point and end point using frequency and amplitude of sound. Second process is extraction of features and third process is classification of features for given segments. As a result of the experiment, the recognition rate of the proposed method is over 90%. And, the recognition rate of the proposed method increased about 20% than the conventional algorithm. Therefore if there are developed portable assistive devices which use developed method to recognize environment sound for hearing-impaired persons, they could be more convenient in life.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.65.3-65
• /
• 2001

In order to apply for pickling line in cold rolling process, a high power magnetostrictive ultrasonic transducer was developed. The transducer is expected to overcome the shortcomings of conventional high power ultrasonic transducers. The transducer consists of Fe-Co-V alloy sheets for the magnetostrictive material, an ultrasonic horn made of Hastelloy to withstand acid solution, and electric driving circuit. In the development, the transducer was designed with the theoretical and numerical methods such as finite element method, and was characterized with experimental water tanks. The developed transducers turned out to be able to generate the sound pressure up to 20,000 Pa, and to be suitable for application ...

• Korean journal of applied entomology
• /
• v.32 no.1
• /
• pp.76-82
• /
• 1993

Phonotaxis of the African mole cricket, Gryllotalpa africana palisot de Beauvois, was investigated in 1990 and 1992 at the agronomy Experiment Station of Korea Ginseng & Tobacco Research Institute in Hwaseong-gun, Kyonggi-do, Male adults produced calling sounds (calling songs) through the openings of subsurface burrows. Intensities of the sound were 77-80 dB at 15 cm above the openings. When tape recordings of male calling songs were broadcasted outdoors at 105-110 dB by two horn speakers installed at the center of a 1.4 m diameter-funnel, flying adults were attracted for 1.5 hours from about 30 minutes after sunset. Among attracted adults, 14.3-16.9% landed in the funnel, and 65.7-74.7% landed on the ground within 2m form the sound source. Females were 66.7-74.3%, which seemed to be due to the sex ratio of the population in the field. Adults landing in the funnel and at the distance of within 2m from the center of the funnel were tend to be a little more than those attracted to a blacklight trap.