Return of the MessiahReturn of the Messiah

ISMA 2017ISMA 2017

Modal Analysis and Bridge Admittance ModelingModal Analysis and Bridge Admittance Modeling

Chris Chafe, Esteban Maestre, Augusto Sarti, Antonio Chris Chafe, Esteban Maestre, Augusto Sarti, Antonio Canclini, Gary Scavone, Julius Smith, Fabio AntonacciCanclini, Gary Scavone, Julius Smith, Fabio Antonacci

toward playing the (modeled) Messiah

(this presentation)

Phase 1: model instrument body modes and “fix” the crack

(next)

Phase 2: incorporate waveguide strings and a bow model with simplified thermal friction and hair dynamics

(and then)

Phase 3: performance rendering from gesture capture

(result – an open string strum)

Phase 1: model instrument body modes and “fix” the crack

click here

the crack

In 1775 Paolo Stradivari contracted to sell the 10 remaining instruments from his father's workshop to Count Cozio di Salabue, one of the most important collectors in history; and although Paolo died before the transaction was concluded, Salabue acquired the instruments. Salabue, who noted the existence of a hairline crack, kept the 'Messiah' until 1827, when he sold it to Luigi Tarisio, a fascinating character who, from small beginnings, built up an important business dealing in violins. However, Tarisio could not bear to part with this instrument. Instead, he made it a favorite topic of conversation, and intrigued dealers on his visits to Paris with accounts of this marvelous 'Salabue' violin, as it was then called, taking care, however, never to bring it with him. One day Tarisio was discoursing to Vuillaume on the merits of this unknown and marvelous instrument, when the violinist Delphin Alard, who was present, exclaimed: 'Then your violin is like the Messiah: one always expects him but he never appears' ('Ah, ça, votre violon est donc comme le Messie; on l'attend toujours, et il ne parait jamais'). Thus the violin was baptized with the name by which it is still known.

the crack

Tarisio never parted with the violin and not until his death in 1854 had anyone outside Italy seen it. In 1855, Vuillaume was able to acquire it, and it remained with him, also until his death. Vuillaume guarded the 'Messiah' jealously, keeping it in a glass case and allowing no one to examine it. However, he did allow it to be shown at the 1872 Exhibition of Instruments in the South Kensington Museum, and this was its first appearance in England. After Vuillaume's death in 1875, the violin became the property of his two daughters and then of his son-in-law, the violinist Alard. After Alard's death in 1888, his heirs sold the 'Messiah' in 1890 to W.E. Hill and Sons on behalf of a Mr. R. Crawford of Edinburgh for 2,600 British pounds, at that time the largest sum ever paid for a violin.

fix the crack

(need a second similar instrument, one that’s not cracked)

Loen, J. S. Fingerprints under the varnish: Comparing thickness graduations of the "Messiah" violin to the golden age Strads. CASJ, Vol. 4, No. 6, p. 14-16. Nov. 2002

Cremonese / Messiah

Cremonese Messiah Cremonese Messiah

horizontal and vertical violin bridge admittance and radiativitymeasurement using a calibrated impact hammer, laser dopplervibrometer (ldv) and microphones

identical measurementsof

detuned Cremonese

at pitch Cremonese

detuned Messiah

(to infer Messiah at pitch)

detuned Cremonese detuned Messiah

at pitch Cremonese

bridge admittanceradiativity(horizontal direction, raw and smoothed)

compare smoothed measurements of – detuned Cremonese (blue)– at pitch Cremonese (red)

compare smoothed measurements of – detuned Messiah (blue)– detuned Cremonese (red)

admitance and reflectance are modeled with filters

methods are detailed in:

admittance models

(excited by white noise for comparison)

detuned Messiahat pitch Cremonese

click here

mode identification for matchingdetuned Cremonese (blue)at pitch Cremonese (red)– mode numbering is per model –

– matches are in black –

mode matching and mappingmode peak correspondences

frequency ratio amplitude ratio

bandwidth (at -3dB) ratio

frequency-dependent ratios of at pitch / detunedderived from matched modes

at pitch Messiah (red)inferred from detuned Messiah (blue)using frequency-dependent ratiosderived from Cremonese models

Plucked strings are obtained by using one-dimensional admittance and reflectance with approximately 50 modes.

One-dimensional digital waveguides simulate the transversal motion of coupled open strings, including recursive low-pass filters to simulate losses. Ideal plucks are recreated by string velocity intialization.

Strum comparison across 3 different violins (models):

detuned models

mapped models

at pitch Cremonese

detuned models

Cremonese: detuned, at pitch, mapped

2

1

3

click here

1 Cremonese

2 Messiah

3

click here

2

1 Messiah

3 Messiah

click here

1

2 Cremonese

3 Messiah

click here

Next stage: bridge admittance and radiativity in 2 directions

International team

(Cremona September, 2016)Canclini, Maestre, Sarti, et al.

(CCRMA June, 2017)Chafe, Smith

(ISMA / McGill June, 2017) Antonacci, Maestre, Scavone