Dichotic listening studies have shown that information relevant to listeners, such as their own name, can be recognized even when presented to the unattended ear. Here, we used a dichotic listening paradigm to explore whether Japanese listeners could identify their name in the unattended ear even when sensory information was incomplete. The results showed that Japanese listeners with family names of 3, 4, or 5 morae — a speech unit equivalent to a syllable in English — recognized their name in about 20–60% of the trials even when the first or the last mora of the name was omitted. The data further showed a name-final effect under the 4- and 5-morae conditions: name recognition significantly decreased when the last mora of the listener’s name was omitted as compared with the omission of the first mora. A possible explanation for these results is that self-relevant information, even when incomplete, automatically draws attention to the supposedly unattended ear and that the listener’s recognition of the information is more robust when its end part is presented.
To determine the best acoustic variables to discriminate the affricate [ts] and fricative [s], word materials produced by single- and multi-Japanese speakers were analyzed. An intensity envelope of a rise, steady, and decay part of [ts] and [s] was respectively approximated by a linear line with positive, zero, and negative slopes, and duration of the each part was measured manually and automatically. Discriminant analyses gave the smallest discriminant error with a combination of a rise part duration and sum of a steady and decay part duration in all combinations of methods for measuring duration (manual and automatic) and speakers of word materials (single and multi). This result strongly suggests that the best variables to discriminate the affricate [ts] and fricative [s] are a combination of the rise duration and the sum of steady and decay durations.
A tremolo produced by irregular plucking of a mandolin is characterized by the average plucking rate, as well as the onset and amplitude deviations. The fluctuation of a tremolo elicited by only the average plucking rate is called the “1st fluctuation,” and that elicited by onset and amplitude deviations is called the “2nd fluctuation.” The procedure for estimating the fluctuation strength, which represents the sensation of hearing fluctuation from sounds, such as amplitude-modulated or frequency-modulated sounds with only the 1st fluctuation, has been developed. However, a procedure for a tremolo with both 1st and 2nd fluctuations has not been investigated. Therefore, we developed a procedure for estimating fluctuation strength from a tremolo produced by irregular plucking of a mandolin. We calculated the feature parameters of a tremolo, and estimated fluctuation strength from the tremolo using the calculated parameters. We found that this procedure that is based on not only the 1st fluctuation but also the 2nd fluctuation approximately represents the sensation of hearing fluctuation (adjusted R2=0.76), and is better than the representation obtained using a procedure based on conventional methods (R2=0.58). Thus, we developed a procedure for estimating fluctuation strength from a tremolo produced by irregular plucking of a mandolin.
The playability of various snare drums has been investigated. Although snare drums are very popular, the differences in their playability have not been reported. Here, the motions in performances using an acoustic snare drum (AD) and three electronic snare drums (ED1, ED2, and ED3) were analyzed, and the relationship between the characteristics of rebound and electromyograms (EMG) on the players’ arms was investigated. The rebound coefficient as the characteristic of rebound was used to obtain the difference in the drumhead for each snare drum. Ten drummers (five professional and five intermediate players) were asked to play single strokes in sixteen measures under five different tempi. Surface EMG signals from their performances on four different snare drums were recorded. Drummers were instructed to play the drums under two different strengths of 40 and 70% of their maximum EMGs by observing their EMGs in real time. (Our system was used to display EMGs.) Surface EMG signals of the flexor carpi ulnaris muscle and extensor carpi ulnaris muscle of both arms were then measured. EMG signals upon playing ED1, ED2, and ED3 were compared with those for playing AD. Obtained EMGs of intermediate players playing the electric drum with the highest rebound coefficient were found to be stronger than those for playing the acoustic snare drum, whereas those of professional were found to be less, implying that only professional drummers can take advantage of the rebound feature to suppress the physical load when drumming.
In the present paper, we describe vibroacoustic coupling between structural vibrations and the internal sound fields of thin structures. A cylindrical structure with thin plates at both ends is considered, and the coupling between the plate vibrations and the internal sound field is obtained when external harmonic forces are applied to both plates. This coupling is theoretically and experimentally investigated by considering the behavior of the plates and the acoustic characteristics of the internal sound field with variations in the harmonic forces. The acoustic characteristics are evaluated on the basis of the sound pressure level, which is maximized while changing the phase difference between the plate vibrations, when the phase difference and relative amplitude between the harmonic forces are varied. The behavior of the plate vibration is investigated by varying the phase difference with the cylinder length. Comparison of the characteristics of the systems reveals that vibroacoustic coupling is effective in increasing the acoustic energy and that the phase difference depends greatly on the acoustic mode, which contributes to the formation of the sound field. Moreover, the experiment of electricity generation verifies that vibroacoustic coupling is effective in the electricity generation system adopted in this investigation, if the coupling phenomena are promoted.