The evolution of musical instrument manufacturing has prompted a quest for innovative materials beyond traditional wood. This review explores the utilization of composite materials, 3D-printed materials, and metamaterials as favorable alternatives. The investigation is driven by challenges such as the scarcity of high-quality tonewoods, variations in wood properties, and environmental concerns. Carbon fiber, graphite fiber, ceramic polymers, and nanocomposites present promising alternatives, offering advantages in durability, weight reduction, and customizable acoustics. The integration of 3D printing technology introduces a cutting-edge dimension, enabling intricate, precisely engineered components, optimizing instrument structure, and allowing unprecedented customization. Additionally, this article explores metamaterials, leveraging unique mechanical properties from structural design rather than constituent materials. Metamaterials offer unprecedented capabilities for tailoring instrument vibrational characteristics by providing unparalleled control over sound production. The review provides a thorough analysis, including manufacturing methods for composite materials, metamaterials, and 3D printing in musical instruments. Comprehensive examinations of vibrational and acoustical analyses related to composite materials, 3D-printed materials, and metamaterials, for the evaluation of musical instruments, are presented. This overview, supported by experimental and numerical simulation methods, offers valuable insights for the future development of musical instruments.

An integrated method, which combines Electronic Speckle Pattern Interferometry, impulse response measurements, finite element method simulations, and psychoacoustic tests, is proposed to evaluate the vibroacoustic behavior of a carbon fiber bouzouki. Three of the carbon fiber instruments are manufactured, and one is qualified via interferometric experimental measurements with reference to a traditional wooden bouzouki, which was evaluated for its sound and playability by the proposed method. Psychoacoustic tests were used to evaluate the sound and playability of the newly qualified carbon fiber bouzouki, which was further modeled by the finite element method and simulated. The simulation results agreed well with the experimental measurements. Furthermore, finite element simulation results of the qualified carbon fiber bouzouki were demonstrated with reference to the traditional wooden bouzouki experimental results, providing new findings crucial for the optimization of the manufacturing and the vibroacoustic behavior of the carbon fiber instrument. The proposed integrated method can be applied to a variety of carbon fiber stringed musical instruments.

The present study encompasses a thorough analysis of the vibrations in a splash musical cymbal. The analysis is performed using a hybrid methodology that combines experimental measurements with parametric computer-aided design and finite element method simulations. Experimental measurements, including electronic speckle pattern interferometry, and impulse response measurements are conducted. The interferometric measurements are used as a reference for the evaluation of finite element method modal analysis results. The modal damping ratio is calculated via the impulse response measurements and is adopted by the corresponding simulations. Two different approximations are employed for the computer-aided design and finite element method models: one using three-point arcs and the other using lines to describe the non-smooth curvature introduced during manufacturing finishing procedures. The numerical models employing the latter approximation exhibit better agreement with experimental results. The numerical results demonstrate that the cymbal geometrical characteristics, such as the non-smooth curvature and thickness, greatly affect the vibrational behavior of the percussion instrument. These results are of valuable importance for the development of vibroacoustic numerical models that will accurately simulate the sound synthesis of cymbals.

A novel 3D auto-drum machine system for the generation and recording of percussion sounds is developed and presented. The capabilities of the machine, along with a calibration, sound production, and collection protocol are demonstrated. The sounds are generated by a drumstick at pre-defined positions and by known impact forces from the programmable 3D auto-drum machine. The generated percussion sounds are accompanied by the spatial excitation coordinates and the correspondent impact forces, allowing for large databases to be built, which are required by machine learning models. The recordings of the radiated sound by a microphone are analyzed using a pre-trained deep learning model, evaluating the consistency of the physical sample generation method. The results demonstrate the ability to perform regression and classification tasks when fine tuning the deep learning model with the gathered data. The produced databases can properly train machine learning models, aiding in the investigation of alternative and cost-effective materials and geometries with relevant sound characteristics and in the development of accurate vibroacoustic numerical models for studying percussion instruments sound synthesis.

The complex frequency domain assurance criterion is here applied for the comparison of a pristine to an altered state of a vibrating system. The criterion was originally proposed for the detection of defects in vibrating structures, while in later research studies it has been successfully used in musical acoustics. In this paper, we evaluate the differences in the vibrational behavior of finished and non-finished cymbals by adopting the proposed correlation criterion. Since idiophones are playable and produce sounds after any manufacturing process, the methodology presented correlates the vibrational state of a cymbal, at any stage of manufacturing, to a reference pristine cymbal. The evaluation of the cymbals is performed by the comparison of finished cymbals with semi-finished and blank 8-inch cymbals of the same material. The correlation criterion is applied to the vibrational measurements of blank, semi-finished, and finished B8 and B20 cymbals. Additionally, commercially available finished cymbals of the same material and geometrical characteristics are introduced in this correlation study. The measuring methodology and the vibration symmetry are discussed, and valuable results and conclusions are presented. The proposed methodology highlights the influence of the manufacturing processes of forming, hammering, and finishing on the vibrational behavior of cymbals, offering manufacturers and drummers a quantifiable criterion for evaluating cymbals’ vibroacoustic performance. Representative evaluations of blanks, semi-finished, and finished cymbals demonstrate the capability of the correlation criterion to monitor, identify, and visualize the vibrational state of any cymbal compared to a pristine reference. This enables the development of a novel methodology for both manufacturers and musicians.

This work describes an integrated method for the investigation of the vibrational characteristics of 3D printed tzouras top plates. The top plates vary in thickness, in tandem to the dimensions of a wooden instrument. The frequency response of the manufactured top plates is determined by modal measurements and the vibration modes are visualized using holographic imaging and further compared to finite element simulation results. The measurements reveal insights applicable to the manufacturing of the instrument by alternative and modern materials. Further analysis includes measuring the vibrational characteristics of a functional wooden tzouras. To gradually implement the transition from traditional to alternative materials, the detached wooden top plate of the instrument is also studied. A correlation criterion is used to compare the responses of the traditional instrument and the top plates for improving their vibroacoustic performance.