Holografska interferometrija nudi mogućnosti analize oscilacija i vibracija različitih objekata - izmedju ostalog i muzičkih instrumenata. Tehnika usrednjavanja ili stroboskopska tehnika omogućavaju da se na telu instrumenta uoče tamne i svetle linije, koje odgovaraju tačkama u različitim stanjima oscilovanja. Takodje, koriste se i metode akustičke holografije. Na taj način je moguće videti različite prostorne modove oscilovanja muzičkog instrumenta.

Erik V. Jansson, Nils-Erik Molin, Henrik O. Saldner
On eigenmodes of the violin—Electronic holography and admittance measurements
The Journal of Acoustical Society of America, Vol. 95, (1994), p. 1100-1105

The present experimental investigation, using recently assembled advanced electro-optical equipment for vibration analysis of three violins, was conducted to seek answers to three questions. A general or global question: Which parts of the violin body are vibrating the most? And two questions related to tonal quality: Are basic low-frequency vibration modes of a musically superior instrument different from those of an inferior violin? Can some special vibration properties be found to support the ``bridge hill?'' Optically obtained vibration modes were recorded as well as frequency responses in the form of admittance measurements. The investigation showed that the vibration modes found earlier are representative both for the inferior violin and the musically superior instruments, although discrepancies can be seen, both in eigenmode shapes and admittance responses. The experimental results are also in quite good agreement with published results of the modal analysis of a violin. Further, the experimental results indicate that the transversal vibrations are mainly within the plates, but at low frequencies, the vibrations of the edges and of the ribs can be large and in-plane as well as transversal. At higher frequencies, the transversal vibration amplitudes are small at the plate edges and larger inside. The top plate tends to have the largest amplitude of vibrations. In the 2.5-kHz range the violin with the most clear ``bridge hill'' tends to have the largest vibrations of the plates.

Henrik O. Saldner
Phase-stepped television holographic technique for measuring phase and amplitude maps of small vibrations
APPLIED OPTICS Vol. 35, (1996), p. 3791-3798

Anna Runnemalm, Nils-Erik Molin
Air cavity modes in sound boxes recorded by TV holography (A)
The Journal of Acoustical Society of America, Vol. 105, (1999), p. 1125

Amplitude and phase distribution of air cavity modes in a rectangular box, in a guitar, and in a violin are measured using TV holography. The box and the top and back plates of the guitar and the violin are made transparent using 5-mm-thick and flat PMMA plates. Standing waves in the enclosed cavities are generated by a loudspeaker. Object laser light is sent through the cavities to a rigid white-painted steel block and reflected back again through the cavities to the optical unit of the TV holography interferometer. Laser light traveling through a sound pressure field will experience a phase delay, since an increased air pressure is accompanied by a higher air density as well as a higher index of refraction which in turn gives a slower speed of the laser light, which generates a phase delay compared to undisturbed air. This often small phase change is made visible by the highly sensitive phase-modulated TV holography technique. The optical system will be described and air cavity modes in a simple rectangular box, in a guitar, and in a violin will illustrate the presentation.

Anna Runnemalm, Nils-Erik Molin, Erik V. Jansson
On operating deflection shapes of the violin body including in-plane motions
The Journal of Acoustical Society of America, Vol. 107, (2000), p. 3452-3459

Earlier investigations have assumed only "out-of-plane" vibrations of the plates of the violin. The violin body can, however, be described as a thin-walled, double-arched shell structure and as such it may very well elongate in one direction as it contracts in another. Therefore, at least two orthogonal vibration components have to be included to describe the vibrations. The operating deflection shapes (ODSs) of a good, professionally made and carefully selected violin were therefore measured in several directions by TV holography to determine both "in-plane" and out-of-plane vibration components of the ODSs. The observations were limited to the frequency range 400–600 Hz, as this interval includes two most-prominent resonance peaks of bridge mobility and sound radiation as well as a third poorly radiating resonance. These three peaks clearly showed orthogonal vibration components in the ODSs. The vibration behavior of the violin body, sectioned in the bridge plane, was interpreted as the vibrations of an "elliptical tube" with nodal diameters. The number of nodal diameters increases from two to three in the selected frequency range. The TV holography measurements were supported by electrodynamical point measurements of bridge mobility, of air volume resonances, and by reciprocity, of radiation properties. Furthermore, a fourth mode, the air mode, A1, is involved indirectly in the sound radiation via influence on the body vibrations.

Nils-Erik Molin, Anders O Wahlin, Erik V. Jansson
Transient wave response of the violin body
The Journal of Acoustical Society of America, Vol. 88, (1990), p. 2479-2481

In this investigation, the dispersive, transient wave propagation field of a complete violin excited by a mechanically induced impulse at the top of the bridge is presented. By means of double pulsed holographic interferometry with a ruby laser as light source the propagating wave field is recorded. From presented interferograms, it is seen that initially the top plate acts mainly as a nonsymmetric dipole with centers at the two bridge feet. The back plate is strongly coupled to the motion of the top plate by the sound post and acts more like a monopole. Thus the position of the sound post is crucial to the performance of the instrument. The free edges at the f-holes are very early reached by the dispersive bending waves of high amplitude probably giving a significant contribution to the sound of the violin family instruments.

Lars H. Morset
An investigation of vibrational and acoustical properties of the violin using MLS and optical holography (A)
The Journal of Acoustical Society of America, Vol. 105, (1999), p. 1127

In this investigation a multi-channel MLS (maximum length sequence) measurement system is used for vibrational and acoustical measurements on the violin. MLS measurements are useful since both phase and magnitude can be measured with great accuracy. In these measurements, both the phase and magnitude influence of the transducers are corrected. Using this tool, the input admittance, the velocity at the feet of the bridge, and the sound pressure at the far field of the violin are measured simultaneously. These parameters give important information about the vibrational and acoustical properties of the violin. A more extensive investigation is also performed. The sound level pressure and phase are measured in several equally spaced positions in the far field of the violin situated in an anechoic chamber. Radiation patterns are found for each mode and the radiated power is calculated. Optical holography is then used to measure the vibrational pattern for the most important modes of the violin body. These acoustical and vibrational measurements are correlated to determine which modes are most important to the radiated sound power.

            Izgleda da je na polju akustike muzičkih instrumenata Erik V. Jansson (Department of Speech Communication and Music Acoustics, Royal Institute of Technology (KTH), P.O. Box 700 14, S-100 44 Stockholm, Sweden ) poseban autoritet. Na sajtu grupe za Govor, muziku i sluh http://www.speech.kth.se/music/acviguit4/index.html data je serija tekstova o Akustici za graditelje violina i gitara.

           Ako i ljudski glas shvatimo kao muzički instrument, onda je interesantna holografska analiza vibracija kože tokom pevanja. Prikazano u radu: