How a violin’s f-holes influence its sound

How a violin’s f-holes are shaped can influence the instrument’s lowest notes.

MIT scientists, along with a Boston-based violin maker, analyzed how air moves through a violin’s f-shaped holes and through the round, half-moon and C-shaped sound holes of violin ancestors from the 10th to 16th centuries. Air accelerates more quickly through the long, narrow f-shaped holes than through round holes, allowing violins to put out more powerful sounds at lower frequencies. The finding, published online February 11 in the Proceedings of the Royal Society A, suggests that the shape of the violin’s holes may have evolved to create slight gains in acoustic power.

Based on calculations of airflow and experiments, the team found that an instrument with f-shaped holes should have twice the acoustic power of one with circular holes. That corresponds to about a three-decibel difference —easily distinguishable by the human ear, which can pick up on 0.5 to 1 decibel changes.

Even slight differences in f-hole length appear to affect the acoustic power of the instrument. The calculations could explain why Amati violins, which have shorter f-holes and less reverberating power, are preferred in small chamber ensembles while Guarneri violins, with longer f-holes and more resonating power, are favored in larger ensembles and concert halls, the scientists say.

They note that this analysis looked at the influence of f-hole shape on the violin’s lowest notes, which is only a small part of the violin’s overall acoustics.