Refer to the section Graduations - top plate for all the information necessary to asses and graduate the plates.
Graduation patterns
a) bulls eye - thicker in the center in the for of a circle
b) spine - thicker along the centerline
For our violin, we will choose the most common bulls eye pattern. This is also the pattern Stradivari used, which is obvious from the average thicknesses in his back plates.
Thicknesses
In Fig. 1 you see the averages for 48 Stradivari back plates. You can distinctly see the bulls eye pattern used here with the thickest part right in the center of the plate. Again, these figures could be a little thicker. A good rule here is that the thickest part should be twice the thickness in the bouts.
Graduating
Rest the back on soft material to prevent dents.
Use a small thumb plane and start removing wood.
Keep checking the M5 frequency and the weight of the plate.
Create a table for your measurements, like the one below, to mark your progress.
Similar rules as of the front plate applies to M1 and M2 frequencies. M2 is a little bit under half of the M5. M1 half of the M2. M2 and M1 is dismissed there, because it can be hard to find on back plate. But the lower the M5, the more they can be heard. I had no problems to find and measure them as long as the M5 is under 440 Hz, but you got to know, what you are looking for. Back plate often tends to accentuate some strange high frequencies and some semimode vibrations. Some makers fine tune their plates to equal the M2 on back and front plate. Some fine tune M5 and M2 into exact octave. Some sources say that you should watch the M2 frequency and keep it above 160 Hz, or the violin sound will resemble viola. It seems M2 influences the timbre of your instrument.
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El método al que hace referencia el comentario pertenece a Isaak Vigdorchik (1929–1987), un lutier ruso-estadounidense que dedicó gran parte de su vida a estudiar acústica de los instrumentos clásicos. Su teoría está detallada en su libro de 1982 titulado "The Acoustical Systems of Violins of Stradivarius and Other Cremona Makers" (Los sistemas acústicos de los violines de Stradivarius y otros fabricantes de Cremona).
A diferencia del método geométrico de grosores (como el patrón de "ojo de buey" o "espina dorsal" mencionado en el texto de la página web) o la afinación general de los modos M1, M2 y M5 de la placa libre, Vigdorchik propuso un sistema mucho más localizado y musical.
Aquí detallo los principios fundamentales de su método de graduación:
1. El concepto de "Notas en la Madera"Vigdorchik poseía un oído absoluto y, al examinar instrumentos clásicos, llegó a la hipótesis de que los grandes maestros de Cremona afinaban sus tapas (delantera y trasera) de modo que resonaran en las 12 notas de la escala musical occidental. En lugar de pensar en el grosor en milímetros, pensaba en el tono musical de cada sector de la madera.
2. Graduación por Franjas o Zonas (Strip Tuning)El núcleo de su sistema de graduación acústica requiere dividir las placas del violín en una especie de mapa topográfico compuesto por franjas, zonas o bandas longitudinales y diagonales. El lutier no rebaja la madera siguiendo un grosor predeterminado, sino que trabaja cada zona de forma individual hasta que alcanza una nota específica.
3. La técnica de afinación por golpeteo (Tap Tones localizados)El proceso de graduación se lleva a cabo de la siguiente manera:Se sujeta la placa de forma que no se ahoguen las vibraciones.Se da un ligero golpeteo (tap) en una franja específica de la madera.Se escucha la frecuencia o tono que emite esa sección concreta.Con un pequeño cepillo curvo o un raspador (scraper), se va retirando madera gradualmente de los puntos altos de esa misma franja. Al quitar masa, el tono o frecuencia de esa área baja.El objetivo es raspar hasta que toda la franja emita un tono perfectamente uniforme y afinado a la frecuencia objetivo de esa zona (por ejemplo, emparejar toda una franja para que resuene exactamente a 198 Hz).
4. Relación armónica entre las placasUna vez que todas las franjas de la tapa superior están afinadas en sus tonos específicos, el proceso se repite en la tapa trasera (la cual, por lo general, se afina en frecuencias ligeramente distintas a las de la tapa superior, manteniendo intervalos específicos). Vigdorchik sostenía que al afinar las placas como un sistema de notas musicales exactas, al ensamblar el violín, toda la caja de resonancia vibraría de forma simpática y armónica, logrando el timbre y la proyección característicos de los instrumentos de Stradivarius.
En resumen, mientras que los métodos modernos a menudo utilizan un generador de tonos y polvo de té para ver las figuras nodales de los modos (Chladni), el método de Vigdorchik es micro-acústico: requiere raspar la placa zona por zona guiándose exclusivamente por el tono localizado que emite la madera al ser golpeada, hasta conformar un mosaico afinado de frecuencias en toda la superficie. - 2026-08-01 18:27:23
The method referred to in the comment belongs to Isaak Vigdorchik (1929–1987), a Russian-American luthier who dedicated much of his life to studying the acoustics of classical instruments. His theory is detailed in his 1982 book titled "The Acoustical Systems of Violins of Stradivarius and Other Cremona Makers."
Unlike the geometric thickness methods (such as the "bullseye" or "spine" patterns mentioned on the webpage) or the general tuning of the M1, M2, and M5 free plate modes, Vigdorchik proposed a much more localized and musical system.
Here are the fundamental principles of his graduation method:
1. The Concept of "Notes in the Wood"
Vigdorchik possessed absolute pitch (perfect pitch) and, upon examining classical instruments, hypothesized that the great Cremonese masters tuned their plates (top and back) so that they resonated at the 12 notes of the Western musical scale. Instead of thinking about thickness in millimeters, he focused on the musical pitch of each specific sector of the wood.
2. Strip Tuning (Graduation by Zones)
The core of his acoustic graduation system requires dividing the violin plates into a sort of topographical map made up of longitudinal and diagonal strips, zones, or bands. The luthier does not thin the wood following a predetermined thickness map, but rather works each zone individually until it reaches a specific note.
3. Localized Tap Tuning Technique
The graduation process is carried out as follows:
The plate is held in a way that does not dampen its vibrations.
A light tap is given to a specific strip of the wood.
The luthier listens to the frequency or pitch emitted by that specific section.
Using a small curved plane or a scraper, wood is gradually removed from the high points of that same strip. As mass is removed, the pitch or frequency of that area drops.
The goal is to scrape until the entire strip emits a perfectly uniform tone, tuned to the target frequency for that zone (for example, matching an entire strip so it resonates at exactly 198 Hz).
4. Harmonic Relationship Between the Plates
Once all the strips on the top plate are tuned to their specific pitches, the process is repeated on the back plate (which is usually tuned to slightly different frequencies than the top plate, while maintaining specific musical intervals). Vigdorchik maintained that by tuning the plates as a system of exact musical notes, the entire soundbox would vibrate sympathetically and harmonically once the violin was assembled, achieving the tone and projection characteristic of Stradivarius instruments.
In summary, while modern methods often use a tone generator and tea leaves or glitter to visualize the nodal figures of the modes (Chladni patterns), Vigdorchik's method is micro-acoustic: it requires scraping the plate zone by zone, guided exclusively by the localized pitch emitted by the wood when tapped, until a tuned mosaic of frequencies is formed across the entire surface. - 2026-08-01 18:25:20
if possible Please provide information about the method of graduation of violin plates according to the method of Mr. Isaac Wikdorchik. Thank you. - 2024-09-29 17:05:17
Those graduations are likely to come from one of my average graduations charts. Anders Buen, Oslo Norway. - 2023-02-11 21:15:58
