A Hidden Gem - What is a Violin Bass Bar?
The Bass-bar* on a violin is 'hopefully' never seen by the violinist unless they are a luthier, as it is fixed to the underside of the Top-Plate of the violin. (A small section of the bass bar can sometimes be seen through the 'f hole' on the bass side of the instrument). It's shape and size are important to both the acoustics and structure of the instrument, as it has two key roles:
i) It adds to the strength of the top plate, working alongside the Soundpost in helping to accommodate the down-pressure created by the strings on the Bridge above.
ii) It helps spread the vibrations across the Top-Plate, improving the sound and projection of the violin.
To achieve this dual role, it must be thick enough to be strong, but thin enough to resonate freely, so the design, position and quality of wood are all important factors. It is a long carved, rectangular piece of wood that runs from the foot of the neck, lengthwise in the same direction as the strings, under the bass-side foot of the Bridge, and on towards the lower end of the violin (nearer the tailpiece). It is thicker in the middle, allowing it to help strengthen the top plate and thinner at the ends to maximise its ability to transmit soundwaves (vibrations) easily.
Whilst the Bass Bar might be 'out of sight' and you rarely hear it spoken of, it really is a 'hidden gem' in the instrument, fulfilling an important role that fundamentally enables your violin to play at its best.
* Below, Fig 1 shows an example of a Bass Bar still in position on a violin that has been dissembled for repair. It clearly illustrates how it is thinner at the ends and thicker near the middle.
For more information about the workings and parts of a violin, what they do and what difference they make to the violin's playability and sound, see our post "What are the parts of a violin and what difference does it make?"
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