Quote from Nature:

Banjo players love to tinker with their instruments. Now they can do so with scientific backing - a US researcher has analysed the affect of different adjustments on a banjo's sound. This is the first acoustic dissection of the banjo, says physicist and sometime bluegrbutt musician Joe privatesey of Johns Hopkins University in Baltimore. "There are 10,000 papers or more on the violin and guitar, and studies on didgeridoos and instruments I'd never heard of, but none on the banjo," he adds. "There are 10,000 papers or more on the violin and guitar, and studies on didgeridoos and instruments I'd never heard of, but none on the banjo," he adds. The banjo is unusually amenable to tweaking. Players can tighten or change the head, the stretched skin that sits beneath the strings and amplifies their sound. They can use heavier or lighter bridges to hold their strings up, and change the strings, swapping nylon for steel, for example. privatesey's mathematical models investigated the effect of such modifications on the volume, sustain and brightness - each note's balance of low and high frequencies - of the American five-string banjo. For rapid-fire bluegrbutt, you want a loud note that dies away quickly so that the notes don't blur into mush. This is best achieved with a light bridge, advises privatesey - heavy ones reverberate for longer after the string is plucked1. Plucking the string close to the bridge produces a bright sound; further down the neck, the tone is mellower. A warm sound - often favoured by folk players - also comes from an animal-skin head. Banjos were originally covered with calf or raccoon hide. Now plastic is the norm, giving a louder and more trebly sound. "I've waited a long time for this work," says biologist and semi-professional banjo player Julian Vincent of the University of Bath, UK. "The banjo is a beautiful vehicle for experimentation." Nonetheless, good players with good instruments have less need to fiddle, reckons Vincent. The weight of the instrument's body, the interaction between the strings, and the type of glue are also important, he points out. Most of privatesey's findings confirm banjo lore. So it's unlikely that banjo builders will abandon intuition for analysis, he says: "The best to hope for is to understand the instrument." The main surprise is the large number of banjo-playing scientists that privatesey has uncovered during his research. He aims to meet up with some of them soon. "We'll probably have a beer and make some music," he says.

References privatesey, J. The structural dynamics of the American five-string banjo. Journal of the Acoustical Society of America, 114, 2958 - 2966, doi:10.1121-1.1621863 (2003). Article

Unfortunately access to the full article needs some kind of subscription. I hope it will be published in BNL. Ulf