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In single-reed instruments, the mouthpiece and reed have an essential effect on instrument playability, since they largely determine the range of lip force and blowing pressure required to produce notes. This paper quantitatively examines the effect of three different mouthpiece designs (Selmer S80, Concept, and Spirit) on the range of lip force and blowing pressure combinations in which tone can be produced on the alto saxophone for notes ranging from D3 to D5. Average lip force, blowing pressure, loudness, and tuning are investigated as functions of notes and for three different reed strengths. Characteristics such as lip-force/blowing-pressure playability area (total playability area, TPA) and correctly tuned playability area (CTPA) are determined for different reed strengths and note values, and change of tuning as a function of notes is investigated. Apparent differences were observed between mouthpieces of different designs and even between mouthpieces with extremely similar tip openings. The Spirit mouthpiece is louder but requires higher lip force and more adaptation of lip force and of blowing pressure over note ranges. The Concept, with a remarkably similar tip opening and facing length as the S80, allows for a smoother transition between the low and high registers of the instrument and has better tuning stability. The new parameters < TPA > and < CTPA > are introduced as summarizing indicators of mouthpiece characteristics, averaged over note range and reed strength range. Such parameters can be used to define mouthpiece playability objectively and can form important input for parameter-based design improvement or customization.

Knowing the precise tympanic membrane (TM) thickness variation is crucial in understanding the functional properties of the TM and has a significant effect on the accuracy of computational models. Using optical coherence tomography, we imaged five left and five right TMs of domestic New Zealand rabbits. From these data, ten thickness distribution maps were computed. Although inter-specimen variability is present, similar features could be observed in all samples: The rabbit TM is thickest around the umbo, with values of 150 32 µm. From the umbo towards the TM annulus, the thickness gradually decreases down to 38 7 µm around the midway location, but increases up to 54 19 µm at the TM annulus. The thickness values at the umbo are comparable to literature data for humans, but the rabbit TM is thinner at the TM annulus and in-between the umbo and annulus. Moreover, the rabbit TM thickness distribution is highly symmetrical, which is not the case for the human TM. The results improve our general understanding of TM structure in rabbits and may improve numerical models of TM dynamical behavior.

An otoendoscopic structured-light system based on fringe-projection profilometry is presented. Two standard rigid otoendoscopes are mounted onto each other and combined with a digital light projector and high-speed camera with respective frame rates of 120 and 210 Hz. Four phase-shifted sinusoidal fringe patterns are projected onto the object’s surface through the imaging channel of one endoscope with a 0° viewing angle, and the fringe patterns reflected by the object are recorded by the camera via the imaging channel of the other endoscope with a 30° viewing angle, resulting in a 3D shape measurement speed of 30 Hz in the current setup. Due to the angle between the projection and imaging axis, the projected patterns appear deformed by the object’s shape to the camera, enabling the reconstruction of its full-field surface height map. Geometric lens distortions in the optics of the projection and imaging channels were calibrated, resulting in a depth measurement precision between 10 and 30 µm and a lateral resolution of 10 to 25 µm. Otoendoscopic profilometry adds an extra dimension of depth to the standard 2D otoendoscopic image and can be used as a noninvasive technique to expand the qualitative depth perception of the physician with quantitative 3D data of the tympanic-membrane surface. Hence, the system holds the potential to provide objective diagnosis of tympanic-membrane and middle-ear disease. In future, the system will be optimized to allow real-time surface-shape visualization and handheld operation for use in a clinical setting.