Archives of Acoustics

The present research investigated the effects of short-term musical training on speech recognition in adverse listening conditions in older adults. A total of 30 Kannada-speaking participants with no history of gross otologic, neurologic, or cognitive problems were divided equally into experimental (M = 63 years) and control groups (M = 65 years). Baseline and follow-up assessments for speech in noise (SNR50) and reverberation was carried out for both groups. The participants in the experimental group were subjected to Carnatic classical music training, which lasted for seven days. The Bayesian likelihood estimates revealed no difference in SNR50 and speech recognition scores in reverberation between baseline and followed-up assessment for the control group. Whereas, in the experimental group, the SNR50 reduced, and speech recognition scores improved following musical training, suggesting the positive impact of music training. The improved performance on speech recognition suggests that short-term musical training using Carnatic music can be used as a potential tool to improve speech recognition abilities in adverse listening conditions in older adults.

The different mechanical properties of the materials from which the tailpieces are made have a noticeable effect on the acoustic performance of the violin. These elements are made today from ebony, rosewood, boxwood, aluminium, or plastic. The aim of this study was to check the exact impact of tailpieces made of different materials on the frequency response function (FRF) of a violin’s bridge and the timbre of the instrument’s sound. For this purpose, the bridge FRF measurement was carried out, and a psychoacoustic test was conducted. The material from which the tailpiece is made to the greatest extent affects the modal frequencies in the range 530–610 Hz (mode B1+), which mainly manifested itself in a change in the instrument’s timbre in terms of the brightness factor. The study showed that the lighter the tailpiece, the darker the sound of the violin. It was also revealed that the selection of accessories affects factors such as openness, thickness, and overall quality of the sound.

The Franssen illusion, or Franssen effect (FE), is one of the auditory spatial illusions. Few studies have explored the FE, and the mechanisms underlying it remain unknown. The present study was conducted to clarify the FE occurrence with different tasks and presentation modes in young adults. It also sought to investigate possible neurophysiological similarities between interaural time difference (ITD) cue processing and FE perception. FE perception was evaluated using two different tasks and two presentation modes (i.e., insert phones and loudspeakers). Sound reflections (reverberation) were presented in the diffuse field (loudspeaker mode). ITD performance was investigated using different stimuli delivered via insert phones. No significant difference between the two FE perception tasks was found ( F _1,25 = 0.138, p = 0.713). However, the FE perception showed a significant difference between the two presentation modes (F _1,25 = 434.03, p < 0.001). Spearman’s correlation did not reveal a significant relationship between FE perception and ITD scores ( p > 0.05).
The current findings show the importance of reverberation in the FE occurrence. Also, the non-significant correlation between the results of the behavioral binaural temporal resolution test and FE perception in young people with normal temporal resolution may indicate that room reflections (reverberation) complicate the ability to process ITDs (rather than poor ITD processing for the “steady state” portion of signal).

Recent papers and studies over the course of last three years have shown that COVID-19 has a negative impact on the speech communication quality between people. This paper presents an influence analysis of the curvature shape of protective transparent shields on the speech signal. Five shields made of the same material and dimensions but with different curvatures were analyzed, from a completely flat to a very curved shield which has the same shape of curvature at its top and bottom and covers the entire face. The influence of the shield is analyzed with two types of experiments – one using dummy head with integrated artificial voice device, and the other using real speakers (female and male actors). It has been shown that usage of protective shields results in a relative increase in the speech signal level, in the frequency range of around 1000 Hz, compared to the situation when protective shields are not used. The relative increase in speech signal levels for large-curvature shields can be up to 8 dB. The possible causes of this phenomenon have been analyzed and examined.

This work aims to further compensate for the weaknesses of feature sparsity and insufficient discriminative acoustic features in existing short-duration speaker recognition. To address this issue, we propose the Bark-scaled Gauss and the linear filter bank superposition cepstral coefficients (BGLCC), and the multidimensional central difference (MDCD) acoustic feature extracted method. The Bark-scaled Gauss filter bank focuses on low-frequency information, while linear filtering is uniformly distributed, therefore, the filter superposition can obtain more discriminative and richer acoustic features of short-duration audio signals. In addition, the multi-dimensional central difference method captures better dynamics features of speakers for improving the performance of short utterance speaker verification. Extensive experiments are conducted on short-duration text-independent speaker verification datasets generated from the VoxCeleb, SITW, and NIST SRE corpora, respectively, which contain speech samples of diverse lengths, and different scenarios. The results demonstrate that the proposed method outperforms the existing acoustic feature extraction approach by at least 10% in the test set. The ablation experiments further illustrate that our proposed approaches can achieve substantial improvement over prior methods.

The flow-induced noise mechanism of a 5000 rpm high-speed gear pump is explored. On the basis of the CFD technology and the Lighthill acoustic analogy theory, a numerical model of the flow-induced noise of a high-speed gear pump is constructed, and the effect of oil suction pressure (0.1–0.2 MPa) on the internal flow field and flow-induced noise characteristics of the high-speed gear pump is investigated. To evaluate the accuracy of the numerical simulation, a noise testing platform for high-speed gear pumps was developed. Adding an oil replenishment groove to the high-speed gear pump suppresses its flow-induced noise. The results indicate that the discrete noise at the fundamental frequency and its harmonic frequency is the primary component of the flow-induced noise of the pump and that the oil-trapped area is the principal source of vibration. The overall sound pressure level of flow-induced noise in the inlet and outlet areas decreases with distance from the oil-trapped area, and the sound pressure level in the outlet area is greater than that in the inlet area. The oil replenishment groove may considerably minimize cavitation noise, enhance the oil absorption capacity, and reduce the outer field’s overall sound pressure level by 4–5 dB.