Using electronic TV holography, we have studied the vibrational modes of four mandolins and a mandola. The lowest (0,0) modes may appear either as a triplet (as in a guitar) or as a doublet. The modal frequencies correlate well with the frequency response curves. Sound spectra indicate that sound radiation is quite uniform over the 0–5 kHz range with some rolloff above 2.5 kHz.
In order to track a rapid transient of pitch, a required frame length of some conventional pitch detection methods is too long. Although there are wavelet based pitch detection methods which require only a few periods of pitch for a frame, they are not robust enough against noise. This paper proposes a new pitch detection method which can work properly under noisy environments even if a frame duration is short. The proposed method consists of a power level detector, a signal analyzer, an autocorrelator, a voiced-unvoiced detector and a lag time interpolator. The signal analyzer is based on the continuous wavelet transform using a harmonic analyzing wavelet. Usage of the harmonic analyzing wavelet gives us more information about a pitch in a scalogram. Simulations of pitch detection for a harmonic chirp signal and speech signals are performed. Performances are compared with two conventional pitch detection methods, cepstrum and modified correlation methods. As a result, a performance of a pitch detection by the proposed method under a noisy environment is better than that of the other two conventional methods. In particular, the largest improvement of performance is obtained for male voices.
We have already developed a novel ultrasonic-based method, namely, the phased tracking method, to measure the rapid velocity in the heart wall by accurately tracking the movement in the heart wall. By applying this method to in vivo experiments, the velocity signal of the heart wall with small amplitude, less than several micrometers on the large motion resulting from a heartbeat, can be successfully detected. There are high frequency components of up to several hundreds Hertz, which have not been previously investigated at all. In this study, after the papillary muscle had been extracted from an isolated rat heart, it was electrically stimulated, and the resultant muscular vibration was directly measured in the frequency range up to 2 kHz using a laser Doppler velocimeter in order to confirm if the high frequency vibrations occur during contraction and relaxation. For the injured myocardium, the power increase in the high frequency components becomes smaller. The experimental results support the hypothesis that the high frequency components are included in the velocity signal measured for the first time in the human interventricular septum by the phase tracking method using ultrasound.
A new Technical Report of Japanese Industrial Standard, JIS/TR S 0001, was made public in January 2002. This JIS/TR is a database for determining the acoustic properties of auditory signals used in consumer products; it consists of (1) graphical data of the frequency characteristics of domestic sounds, and (2) a library of recorded sounds on compact disc. The former can be used to graphically determine combinations of frequency and sound pressure level of auditory signals that are audible against domestic sounds. The latter is intended for use in a psychoacoustic experiment in which auditory signals are presented along with domestic sound(s) of the library; listeners are asked then to judge how they perceive the signals. The experiment can be carried out using either a loudspeaker or headphones. This JIS/TR will facilitate the development of suitable auditory signals for domestic appliances used under various noisy conditions and by a variety of users, including the elderly.
The purpose of this paper is to present the concept and design of Technical Listening Training, a systematic education program designed to allow prospective acoustic engineers and sound designers to enhance their auditory sensitivity. Sound professionals should have the ability to express auditory differences using appropriate technical terms for the physical properties of sounds. Furthermore, they should be able to imagine the sounds when given the acoustic properties of the sounds. Training starts with a discrimination task for pitch, loudness, and timbre in order to increase sensitivity to auditory differences. This is followed by instruction on sound property identification to improve students’ ability to correlate auditory impressions with the physical properties of the sound, thereby allowing them to imagine the sound. Through Technical Listening Training, students improve their sound sensitivity and understanding of the relationship between acoustic properties and auditory impression.