Dipartimento di Fisica

Visiting some museums, it may happen to stop in front of showcases with ancient musical instruments inside and to wonder what the sound emitted by these instruments was like.
Musical instruments are a peculiar kind of Cultural Heritage, because in a single object there are two types of cultural property: a material one consisting of the object itself and an abstract one, consisting of the sound emitted by the instrument. Museums often tend to promote the conservation of the first one losing the second one, especially for woodwind instruments. In this way, however, the musical instrument is deprived of part of its meaning: the reason they were created. Therefore, the main goal of this research is to give voice to these
instruments again. Starting from previous studies, focused on the use of Computed Tomography (CT) analysis to observe the state of conservation of different types of musical instruments [1, 2], and referring to indications provided by the previous MUSICES project [3], the aim of that project is to improve a protocol for the analysis of woodwind instruments, using Computed Tomography, in order to create copies,whose sound is comparable to that of the originals, thanks to the use of Selective Laser Sintering (SLS) 3D printers.
CT is a physic technique based on the interaction between X-ray beam and matter of which the sample is composed. Differently from Radiography, the object analysed rotates around its axis and for each position occupied, the detector acquired the transmitted X-ray beam. The CT, in this way, allows the placement in space of the constituent elements of the artwork, providing a three-dimensional interpretation of the results [4]. Therefore, thanks to CT analysis, it is possible to study the state of conservation, to observe and measure internal structure, fractures, cracks, defects, previous restoration work [5].
For the creation of the copies of the woodwind instruments, 3D printers will be used at Selective Laser Sintering (SLS) of Nylon-12 powders. Since the material of the copies is different from the material of the originals, a question naturally arises: how is it possible that the sounds of the two musical instruments, the original and the replica, are the same?
Technically there should be no differences, as, in this type of wind instruments, the sound largely depends on the internal geometry. The sound emitted derives from the vibration of the air column introduced by the musician and not from the vibration of the instrument. A part of the research will be dedicated to verifying what has been stated. Acoustic impedance analyses will be carried out and the sound spectra emitted by the different musical instruments will be compared. Moreover, thanks to the presence of an expert musician, musical scales and reference tunes, played first with the original instrument and then with the replica, will be
compared.
To have a good protocol of analysis and creation of copies of ancient instruments that cannot be played, it is also necessary to:
- perform tomography of the instruments through metrological calibration with appropriate tools, as ball-bars, to further reduce the dimensional differences between sample and replica
- evaluate the influence of the CT setup geometry on the accuracy of the measurements
- standardize the creation of meshes for subsequent printing, eventually finding a objective way to discriminate the wood profile of the tomography from the air
- normalize the finishing procedures of the copies through instrument surface analysis.
Will it be possible to play an ancient Egyptian flute again? I hope yes.

References
[1] Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with
Materials and Atoms. Vol. 336, Oct 2014, p. 63. Festa et al.
[2] Journal of Cultural Heritage. Vol. 27, Oct 2017, p.S78. Den Bulcke et al.
[3] Germanisches National Museum, https://www.gnm.de/en/research/research-
projects/musices/
[4] M. Nervo, Il progetto neu-ART : studi e applicazioni ; Neutron and X-ray tomography and
imaging for cultural heritage, Editris, 2013.
[5] X-ray Computed Tomography Analysis of Historical Woodwind Instruments of the Late
Eighteenth Century”; F. Tansella, L. Vigorelli, G. Ricchiardi, A. Re, L. Bonizzoni, S. Grassini,
M. Staropoli, A. Lo Giudice, Journal of Imaging 8(10), 260 (2022)