Sound Production Mechanisms Research Articles

Recent investigations using an artificial player for brass instruments

Artificial players show great interest for scientific studies on musical instruments: they allow sound production mechanisms to be reproduced, while making it possible to monitor several variables of the system that are usually difficult to measure on human players. In brass instruments, where the reed consists of the lips of the players, several systems have been developed over the years in research laboratories. In order to build artificial lips, one crucial element of the system, different solutions were proposed, such as latex tubes filled with water or rubber sheets. Although very realistic sounds can be obtained with some systems, one difficulty remains to build an apparatus which is relatively easy to control, stable, and repeatable. In this presentation, we will introduce the latest version of the brass artificial player developed in Yamaha and recently at LMA, which is based on a quite efficient, yet relatively simple, solution for the lips. The system then provides ease of use, stability and repeatability, while generating very realistic sounds. We will present some studies conducted with this new apparatus, and also demonstrate a portable version of it, that can trigger some ideas for other applications than research.

Measurement of the friction law between a wet finger and a glass oscillator: Application to the Cristal Baschet

The cristal Baschet is a musical instrument created during the 50's. The produced sound results from vibrations induced by friction between wet fingers and glass rods. Each glass rod is connected to an assembly of threaded shaft and mass, whose dynamic properties determine the frequency of self-oscillation. In this work, an experimental method is proposed to identify the friction law between a wet finger and the glass, with the aim of achieving more accurate modelling of the sound production mechanism. The normal and tangential forces between the finger and the glass rod are identified by solving an inverse problem, from in-situ measurements using accelerometers and a high speed camera. Experimental identification of the friction law therefore makes it possible to estimate its variability with parameters such as the quantity of water or the diversity of fingers.

Hands, Fingers, Strings, and Bows

In this article, I draw on public-facing sources and my violinistic experience to show how attention to performance technique illustrates three different relationships between performance and analysis. In the Largo from J.S. Bach’s Sonata No. 3 for Solo Violin (BWV 1005), multiple-stop chords, string-based affordances, and bowings in turn correspond with, contradict, and create new analytical perspectives. I first collate definitions of interpretation and technique as they relate to performance. Interpretation is non-instrument-specific and deals with decoding and expressing musical meaning; technique is instrument-specific and deals with the granular mechanics of sound production. A multiple-stop intensity model shows that changes in a violinist’s multiple-stop-based effort correspond with significant cadential markers. At the local level, the violinistic “feel” of each quadruple stop aligns with expressive aspects of harmony and form. Heinrich Schenker’s performance recommendations for the Largo’s cadences, by contrast, conflict with a violinist’s experience of how the cadences intersect with instrumental affordances. Although the two perspectives may be reconcilable, actual performances support the instrument-grounded perspective. Finally, I draw on basic bowing motions to create an analytical technique of bowing reduction. My reduction of the Largo reveals a recurring bowing-based motive, which in turn elucidates the source of a performative tension I have experienced when playing the movement. This final example reminds us that technique and interpretation—just like performance and analysis—are inevitably entangled.

Ultrafast sound production mechanism in one of the smallest vertebrates

Motion is the basis of nearly all animal behavior. Evolution has led to some extraordinary specializations of propulsion mechanisms among invertebrates, including the mandibles of the dracula ant and the claw of the pistol shrimp. In contrast, vertebrate skeletal movement is considered to be limited by the speed of muscle, saturating around 250 Hz. Here, we describe the unique propulsion mechanism by which Danionella cerebrum, a miniature cyprinid fish of only 12 mm length, produces high amplitude sounds exceeding 140 dB (re. 1 µPa, at a distance of one body length). Using a combination of high-speed video, micro-computed tomography (micro-CT), RNA profiling, and finite difference simulations, we found that D. cerebrum employ a unique sound production mechanism that involves a drumming cartilage, a specialized rib, and a dedicated muscle adapted for low fatigue. This apparatus accelerates the drumming cartilage at over 2,000 g, shooting it at the swim bladder to generate a rapid, loud pulse. These pulses are chained together to make calls with either bilaterally alternating or unilateral muscle contractions. D. cerebrum use this remarkable mechanism for acoustic communication with conspecifics.

Wing mechanics and acoustic communication of a new genus of sylvan katydid (Orthoptera: Tettigoniidae: Pseudophyllinae) from the Central Cordillera cloud forest of Colombia.

Stridulation is used by male katydids to produce sound via the rubbing together of their specialised forewings, either by sustained or interrupted sweeps of the file producing different tones and call structures. There are many species of Orthoptera that remain undescribed and their acoustic signals are unknown. This study aims to measure and quantify the mechanics of wing vibration, sound production and acoustic properties of the hearing system in a new genus of Pseudophyllinae with taxonomic descriptions of two new species. The calling behaviour and wing mechanics of males were measured using micro-scanning laser Doppler vibrometry, microscopy, and ultrasound sensitive equipment. The resonant properties of the acoustic pinnae of the ears were obtained via μ-CT scanning and 3D printed experimentation, and numerical modelling was used to validate the results. Analysis of sound recordings and wing vibrations revealed that the stridulatory areas of the right tegmen exhibit relatively narrow frequency responses and produce narrowband calls between 12 and 20 kHz. As in most Pseudophyllinae, only the right mirror is activated for sound production. The acoustic pinnae of all species were found to provide a broadband increased acoustic gain from ~40-120 kHz by up to 25 dB, peaking at almost 90 kHz which coincides with the echolocation frequency of sympatric bats. The new genus, named Satizabalus n. gen., is here derived as a new polytypic genus from the existing genus Gnathoclita, based on morphological and acoustic evidence from one described (S. sodalis n. comb.) and two new species (S. jorgevargasi n. sp. and S. hauca n. sp.). Unlike most Tettigoniidae, Satizabalus exhibits a particular form of sexual dimorphism whereby the heads and mandibles of the males are greatly enlarged compared to the females. We suggest that Satizabalus is related to the genus Trichotettix, also found in cloud forests in Colombia, and not to Gnathoclita.

Functional plasticity of the swim bladder as an acoustic organ for communication in a vocal fish.

Teleost fishes have evolved a number of sound-producing mechanisms, including vibrations of the swim bladder. In addition to sound production, the swim bladder also aids in sound reception. While the production and reception of sound by the swim bladder has been described separately in fishes, the extent to which it operates for both in a single species is unknown. Here, using morphological, electrophysiological and modelling approaches, we show that the swim bladder of male plainfin midshipman fish (Porichthys notatus) exhibits reproductive state-dependent changes in morphology and function for sound production and reception. Non-reproductive males possess rostral 'horn-like' swim bladder extensions that enhance low-frequency (less than 800 Hz) sound pressure sensitivity by decreasing the distance between the swim bladder and inner ear, thus enabling pressure-induced swim bladder vibrations to be transduced to the inner ear. By contrast, reproductive males display enlarged swim bladder sonic muscles that enable the production of advertisement calls but also alter swim bladder morphology and increase the swim bladder to inner ear distance, effectively reducing sound pressure sensitivity. Taken together, we show that the swim bladder exhibits a seasonal functional plasticity that allows it to effectively mediate both the production and reception of sound in a vocal teleost fish.

On the Alignment of Acoustic and Coupled Mechanic-Acoustic Eigenmodes in Phonation by Supraglottal Duct Variations.

Sound generation in human phonation and the underlying fluid-structure-acoustic interaction that describes the sound production mechanism are not fully understood. A previous experimental study, with a silicone made vocal fold model connected to a straight vocal tract pipe of fixed length, showed that vibroacoustic coupling can cause a deviation in the vocal fold vibration frequency. This occurred when the fundamental frequency of the vocal fold motion was close to the lowest acoustic resonance frequency of the pipe. What is not fully understood is how the vibroacoustic coupling is influenced by a varying vocal tract length. Presuming that this effect is a pure coupling of the acoustical effects, a numerical simulation model is established based on the computation of the mechanical-acoustic eigenvalue. With varying pipe lengths, the lowest acoustic resonance frequency was adjusted in the experiments and so in the simulation setup. In doing so, the evolution of the vocal folds' coupled eigenvalues and eigenmodes is investigated, which confirms the experimental findings. Finally, it was shown that for normal phonation conditions, the mechanical mode is the most efficient vibration pattern whenever the acoustic resonance of the pipe (lowest formant) is far away from the vocal folds' vibration frequency. Whenever the lowest formant is slightly lower than the mechanical vocal fold eigenfrequency, the coupled vocal fold motion pattern at the formant frequency dominates.

Bioacoustics supports genus identification in piranhasa).

In different teleost species, sound production can utilize specific coding schemes to avoid confusion between species during communication. Piranhas are vocal Neotropical fishes, and both Pygocentrus and Serrasalmus produce similar pulsed sounds using the same sound-producing mechanism. In this study, we analysed the sounds of three Pygocentrus and nine Serrasalmus species to determine whether sounds can be used to discriminate piranha species at both the species and genus levels. Our analysis of temporal and frequency data supports the idea that the sounds of Serrasalmus and Pygocentrus species are species specific, and that different acoustic features can be used to differentiate taxa at the genus level. Specifically, the sounds of Serrasalmus species are shorter, louder, and have a shorter pulse period (as determined after correction for standard length). This suggests that sounds can be used to support taxonomy at the genus level as well as the species level.

Two distinct mechanisms of tonal sound production in supersonic jet impingement

The interaction of high-speed jets with a perpendicular surface produces not only broadband sound, but “impingement tones,” that can be more than 30 dB above the broadband noise. It is well recognized that these tones are the result of an aeroacoustic resonance, driven by a feedback loop between the jet nozzle and the plate. However, the exact mechanism by which the tones are produced remains a topic of some dispute; some researchers locate the source within the core of the impinging jet, others in the wall jet generated after impingement with the plate. In this work, we demonstrate that both camps have correctly identified sources; there are two distinct mechanisms, with two distinct locations. The relative strength of these sources depends on the geometry of the problem, but we show that they can actually coexist at a single condition. Decomposition of high-speed schlieren data directly visualizes the location of these sources as a function of jet operating condition.

Species-specific larval acoustic behaviour of three stag beetles (Coleoptera: Lucanidae), with emphasis on their stridulatory organs and acoustic signals

Acoustic behaviour plays a significant role in insect communications, but is rarely reported in their immature stages. Larvae of Lucanidae bear paired stridulatory organs on their thoracic legs, which could produce sounds as communicational signals. However, the species-specific differences on stridulatory organs and acoustic signals are far from fully investigated. In this study, the larval acoustic behaviours of three lucanid species, Lucanus dybowski, Prosopocoilus confucius and P. girafa were recorded and compared for the first time. The sound producing mechanism was described in detail based on video recordings, morphological observations, and acoustic analyses. The larvae of all three species are able to produce sounds by scraping the plectrum on the metatrochanter against the pars stridens on the mesocoxa during disturbance. The sounds exhibit species-specific differences in terms of acoustic parameters: the larvae of L. dybowski produce short-duration (140–200 ms), single-pulse and low-frequency (∼210 Hz) sounds; P. confucius produce long-duration (500–800 ms), triple-pulse and low-frequency (∼280 Hz) sounds; P. girafa produce long-duration (500–560 ms), double-pulse and low-frequency (∼260 Hz) sounds. The amounts and arrangements of the teeth on stridulatory organs also exhibit differences on specific level. The acoustic signals and stridulatory organs were compared using principal component analysis.

First record of an atypical and non-stridulatory sound produced by the larvae of two species of Dichotomius (Coleoptera: Scarabaeidae) from Argentina

ABSTRACT The following study presents the first record of an atypical sound never reported before produced by the larvae of two species of dung beetles from Argentina, Dichotomius (Luederwaldtinia) carbonarius (Mannerheim 1829) and Dichotomius (Luederwaldtinia) nisus (Olivier 1789). This new sound is produced by the larvae in their three instars by shaking the third pair of legs inside the pupation chamber, which does not involve a stridulatory mechanism. Recorded sounds and video images of the larval behaviour are provided. The oscillograms, spectrograms and possible functions are analysed, and a new sound production mechanism is postulated.

Morphology and phylogenetic significance of a newly discovered sound production mechanism in Passandridae (Coleoptera: Cucujoidea)

Morphology and phylogenetic significance of a newly discovered sound production mechanism in Passandridae (Coleoptera: Cucujoidea)

Implicit and explicit schemes for energy-stable simulation of string vibrations with collisions: Refinement, analysis, and comparison

Collisions play an important role in the sound production mechanism of musical string instruments. Impactive contact modelling must therefore be incorporated in energy-stable time-stepping schemes for simulation and sound synthesis. Recently, explicit and linearly implicit schemes based on energy quadratisation have emerged as a means of numerical modelling of nonlinear string vibrations that avoids the need for iterative solvers, which significantly enhances the applicability to real-time sound synthesis. However when applied to modelling collisions, spurious oscillations and artefacts have been reported, which can be linked to the one-sided nature of the contact force. To investigate whether and how these limitations can be avoided, this paper proposes refined numerical scheme variants for both lumped and distributed contact configurations, and assesses their accuracy and efficiency. For reference, two nonlinearly implicit schemes are also included in the comparisons. Guaranteed correctness of the sign of the numerical contact force is proven for several of the scheme variants. Numerical experiments across three case studies indicate that each of the proposed schemes converges towards the exact solution, and that for sufficiently small time steps, explicit schemes generally perform well compared to implicit schemes.

Piano Soundboard Analysis at Radiated Sound

The piano is a complex musical instrument consisting of several components influencing vibration and sound production. By understanding the sound production mechanism virtual instruments can be created (physics-based sound synthesis) and the design and manufacturing of soundboards can be supported (virtual prototyping). Based on previous results published in the literature, a piano model was built and extended by a near field sound radiation model capable for physics-based sound synthesis. In this paper a simplified piano model is presented, including hammer strike and hysteretic felt models, coupled lossy string model and a 2D FEM based stiffened plate model for soundboard. This paper contains a parametric study where the soundboard parameters, such as its material characteristics and boundary conditions, are modified and their effect on the soundboard's modal behavior and the radiated sound is analyzed. Instead of using only musical (qualitative) descriptors, e.g. brightness or coloring, the piano sounds are characterized based on standard quantitative descriptors (e.g. harmonic ratio, spectral centroid). It is shown that these descriptors are determined by soundboard admittance, string characteristics and position on the soundboard; radiated sound from wooden soundboards can be characterized as harmonic for wide range of initial material descriptors; the string position is essential, and the perceived sound can differ significantly for different listening positions, even for the same harmonic decay pattern.

The dynamics behind diversity in suboscine songs.

Vocal behavior plays a crucial evolutionary role. In the case of birds, song is critically important in courtship, male-male competition and other key behaviors linked to reproduction. However, under natural conditions, a variety of avian species live in close proximity and share an 'acoustic landscape'. Therefore, they need to be able to differentiate their calls or songs from those of other species and also from those of other individuals of the same species. To do this efficiently, birds display a remarkable diversity of sounds. For example, in the case of vocal learners, such as oscine passerines (i.e. songbirds), complex sequences and subtle acoustic effects are produced through the generation of complex neuromuscular instructions driving the vocal organ, which is remarkably conserved across approximately 4000 oscine species. By contrast, the majority of the sister clade of oscines, the suboscine passerines, are thought not to be vocal learners. Despite this, different suboscine species can generate a rich variety of songs and quite subtle acoustic effects. In the last few years, different suboscine species have been shown to possess morphological adaptations that allow them to produce a diversity of acoustic characteristics. Here, we briefly review the mechanisms of sound production in birds, before considering three suboscine species in more detail. The examples discussed in this Review, integrating biological experiments and biomechanical modeling using non-linear dynamical systems, illustrate how a morphological adaptation can produce complex acoustic properties without the need for complex neuromuscular control.

Sound detection and production mechanisms in aquatic decapod and stomatopod crustaceans.

The sensory systems of crustaceans (aquatic decapods and stomatopods) have adapted to a diverse range of aquatic ecosystems. Sound production in aquatic crustaceans is more widespread than previously thought, and has been shown to play a major role in many of their life-history strategies; however, there are still many gaps in our understanding of their sound reception abilities. Crustaceans have three main sensory receptors for sound - the statocyst, superficial hair cells and chordotonal organs - which are all sensitive to the particle motion component of the sound field, rather than the pressure component. Our current understanding of these receptors is that they are sensitive to low-frequency sounds (<2000 Hz). There are a wide variety of sound-producing mechanisms employed by these animals, ranging from stridulation to implosive cavitation (see Glossary). These signals are used for a range of social behaviours, such as courtship, territorial defence and assessing 'resource guarding'. Furthermore, there are examples of sound signals that exceed their hearing range, highlighting a mismatch in our understanding of their hearing systems. This mismatch provides weight to the suggestion that another sound transmission channel - substrate-borne vibrations - might be at play, particularly because most crustaceans live on or near the seafloor. Finally, suggestions are made regarding potential future work that is needed to fill the substantial gaps in our understanding of how crustaceans hear and produce sound.

Acoustic Characterization for The Feeding Activities of Haliotis discus Hannai

In order to analyze the sound production mechanism and the acoustic characteristics of Haliotis discus hannai during feeding, this paper proposes a multi-source information fusion approach combining passive acoustics with videos. In the experiments, abalones with a shell length of 60 ± 2.7 mm were divided into two groups: Group A was fed with fresh macro algae Gracilaria lemaneiformis as food once each day; Group B was placed on a small amount of sand as impurities at the bottom of the tank. As control groups, Group C did not have abalone or food and Group D did not have abalones but food was added. The eating acoustic signals of abalone were mainly concentrated in the frequency range between 9.49 kHz and 44.36 kHz, wherein the peak frequency is 37.86 ± 2.55 kHz, with the maximum energy −66.43 ± 5.17 dBm/Hz. Each pulse sequence is with a duration of 119.12 ± 70.51 ms and consists of several sub-pulses. Nearly 70% of the pulse sequences consist of 1~2 sub-pulses and the duration of the pulse containing one sub-pulse is 42.62 ± 19.72 ms. The eating rate was kept at 0.61 ± 0.04 times/min at the beginning and was decreased significantly to 0.48 ± 0.08 times/min after 60 min. Note that the characteristic analysis of abalone acoustic signals during feeding are first reported in this manuscript to the best of our knowledge, and this paper also demonstrates that the sound of abalone is produced by scraping and grinding food with radula. Because the eating rate decreases with the reduction in the abalone’s level of hunger, the results may be used as an acoustic indicator of feeding strategy for the abalone aquaculture industry.

Main flow oriented vorticity noise experiments

Entropy inhomogeneities and vorticity spots induce so-called indirect combustion noise when passing through a choked nozzle; referred to as entropy noise and vorticity noise, respectively. We note that vorticity noise depends on the orientation of the vorticity; viz., oriented normal or parallel to the axial main flow. An experimental investigation of parallel component vorticity noise is presented. In the experiment a time- dependent swirling flow was induced by unsteady tangential injection in the pipe upstream of a choked convergent-divergent nozzle. As the resulting swirling flow passes through the nozzle, the axial stretching of the fluid caused an increase in rotation energy. The steady energy conservation in an isentropic flow implies a Mach number higher than unity at the throat and an associated reduction of density. Ergo, the critical mass-flow rate (for fixed reservoir pressure and temperature) decreases quadratically with increasing swirl intensity. The acoustic waves radiated downstream of the nozzle are a direct measure for this mass-flow modulation. Using a semi-empirical model, this sound production mechanism is demonstrated to indeed be quasi steady.

Underwater vocalizations of Trachemys scripta elegans and their differences among sex–age groups

The aim of this study was to identify underwater vocalizations in red-eared turtles (Trachemys scripta elegans) and assess differences between sexes and ages. We recorded the underwater vocalizations of the red-eared sliders and identified 12 call types through manual visual and aural inspection of the recordings. Similarity analysis verified that manual classification was relatively reliable. The call types of the turtle were described and displayed as spectrograms and waveforms. The turtles produced fewer high-frequency call types than low-frequency types in all recordings. Statistical analysis revealed significant differences in the frequencies and duration of the calls of red-eared turtles between different sexes and ages. Males vocalized pulse calls very frequently, whereas a high proportion of high-frequency call types was emitted by the female adult group. The male subadult group emitted higher frequencies of Type A, B, and C calls, which is in accordance with the phenomenon that vocal frequency is often inversely proportional to the turtle size. Some call types produced by red-eared turtles were above the frequency range of their known hearing range. This may have been a by-product of the sound production mechanism or it may have adaptive value in mitigating interference to communication from low-frequency noise common in natural waters in communication The behavioral implications of these vocalizations and whether turtles can hear such high sounds warrant further study.

Caterpillar sonic defences: mechanisms and diversity of mandible stridulation in silk and hawk moth (Bombycoidea) larvae

ABSTRACT Silk and hawk moth caterpillars produce a variety of defence sounds described as clicking, chirping, whistling, and vocalising. Such diversity provides opportunity to test hypotheses on the functions and evolution of insect defence sounds using comparative analyses. A key step to conducting comparative analyses is to categorise different phenotypes. Here, we describe mandible sounds of 20 species of late instar Bombycoidea caterpillars and establish objective criteria for differentiating between sound-producing mechanisms. First, we assess how the two mandibular mechanisms – clicking and chirping – differ from one another using two reference species: Antheraea polyphemus (clicker) and Saturnia pyri (chirper). In these references, clicks are produced by ridged and serrated mandibles and have short duration units with few pulses, whereas chirps are produced by scalloped mandibles and have longer duration units with more pulses. Second, we characterise acoustic and morphological traits of 18 additional species. These are categorised as clickers (13 species), chirpers (4 species), or other (1 species) using diagnostic features identified from the reference species. Third, these categorisations are tested using a predictive logistic regression model. The results of this study contribute to our understanding of acoustically mediated defences in caterpillars and provide necessary criteria for conducting further comparative studies.