The tubular bell chime is an orchestral percussion instrument with a naturally inharmonic frequency spectrum. Inharmonic overtones can decrease the perception of clear pitch but spectral tuning for perceptual optimization has not previously been explored for tubular bells. The method uses finite element analysis to solve the inverse spectral problem of designing a harmonic tubular bell, through optimizing locations of diameter reductions to minimize spectral frequency-matching errors with a harmonic series. An initial design was generated using constrained minimization within Timoshenko beam theory. Then, the design was refined using gradient descent of simulated three-dimensional finite element analysis. The final design was prototyped using a manual lathe, and experimentally characterized via frequency response measurements. Prior to modification, the stock material had overtones up to the fifth mode between 24 and 158 ¢ from a fundamental-based harmonic series. Following shape optimization, the first five resonant frequencies of the manufactured chime were between 3 and 12 ¢ away from the target harmonic series, showing a substantial perceptible increase in harmonicity. The results prove that applied local mass and stiffness changes can modally tune a tubular bell, unlocking novel timbral features for chime-type instruments.
Low-intensity pulsed ultrasound is a therapeutic modality used to promote bone regeneration through a process known as mechanotransduction. However, the underlying mechanisms by which ultrasound triggers biological responses remain poorly understood. To gain insight on this phenomenon, in vitro studies are essential, as they provide a controlled environment to correlate acoustic mechanisms with biological responses. In this work, we propose an automated low-intensity pulsed ultrasound stimulator designed for experiments on living cells. This device delivers a controlled acoustic dose to cells cultured in an incubator. Its configuration enables serial stimulation and facilitates parametric studies in order to investigate the physical mechanisms that induce mechanotransduction. The characteristics of the system allow for reproducible experiments with a large number of replicates to perform downstream biological analysis. This device is an essential tool to better understand mechanotransduction and for the development of optimized ultrasound based therapy.
Major depressive disorder (MDD) is a common mental health condition that requires scalable and objective detection methods. Speech is a promising non-invasive digital biomarker, but many existing approaches rely on binary classification, lack interpretable acoustic modeling, and ignore demographic differences that affect speech patterns. This work proposes HEAR-Net, a unified speech-based framework for depression detection and emotion recognition that integrates acoustic features and demographic context. We propose a harmonic block to capture long-range harmonic patterns related to voice quality, a spectro-temporal orthogonal gating mechanism to model time and frequency information, and an entropy-aware pooling to reflect changes in expressive variability. We incorporate age and sex information to provide demographic context alongside acoustic features. Experiments on DAIC-WOZ and MODMA achieve average F1-scores of 0.93 and 0.92, with accuracies of 0.94 and 0.92, respectively. On CASIA and EmoDB, HEAR-Net reaches accuracies of 0.89 and 0.91 without external pre-trained models.
For purely mathematical reasons, many physical models use regularisations to improve the behavior of their numerical implementations. However, the choice of a regularisation is not insignificant, as it can introduce non-physical artifacts. This study argues for the use of physics-based regularisations in numerical models. As an illustration, this option is demonstrated on the pressure-flow characteristic in reed instruments by introducing two regularisations justified by physical considerations. The first concerns the change in flow direction at the reed tip, regularised by introducing the air viscosity into the flow, and is used to study the dynamic behavior of the crumhorn, in particular its period-doubling cascade. The second concerns the closure of the reed-table channel and is based on modeling the reed as a beam with variable boundary conditions subjected to a pressure difference. It is compared to mathematical regularisations from the literature by fitting to measures.
It is a widespread belief among musicians that a violin's sound "opens up" or improves through regular playing. A companion study established, through physical measurements, that no macroscopic physical violin or kinematic player adaptation changes occurred after a Test Violin was "played-in". The present study examines whether the tradition is instead rooted in human perception by testing three hypotheses: (1) the instrument undergoes a perceptually measurable physical evolution, (2) the player undergoes a behavioural adaptation altering their acoustic output, or (3) the player experiences an internal adaptation through prolonged interaction with the instrument. A previously rarely played Test Violin was played daily by a professional soloist for approximately six months, while two Control Violins remained in storage; a blinded Control Group of ten violinists played all three instruments at each session. Assessments incorporated two pre-playing-in sessions spaced one week apart to quantify test-retest variability, blinded violin ratings, pairwise listening tests, and unstructured interviews. Using non-superiority testing, results confirmed that the Test Violin did not undergo a physical evolution perceptible to the Control Group or third-party listeners, nor did the Test Violinist produce a measurable behavioural adaptation in their acoustic output. The soloist's ratings suggested improved Ease of Playing (though not statistically significant), and their verbal comments described a reduced sense of effort and improved tone. These findings suggest that the "playing-in" phenomenon is not driven by physical or behavioural changes, but by processes internal to the player, involving expectation bias and sensorimotor and proprioceptive adaptation through repeated exposure.
