He also worked out how easy hammer-ons and pull-offs are, depending on the height of the guitar strings above the finger board.įinally, he confirmed the equation for string bends experimentally, measuring the frequency of the sound produced for strings bent through different angles on a guitar.ĭr Grimes says: ‘I took one of my oldest guitars down to the engineering lab at Dublin City University to one of the people I knew there and explained that I wanted to strip it down to do this experiment. He found that the properties of the strings had a big effect on the change in pitch – in particular the Young’s modulus (a measure of how much the string stretches under force) and how thick the strings are. In spare time at his previous position at Dublin City University and now at Oxford University, he worked out the physics behind the instinctive playing of the best guitarists.ĭr Grimes derived equations describing how string bending, vibrato and whammy bars change the pitch of a note. I wanted to understand what it was about these guitar techniques that allows you to manipulate pitch.’ĭr Grimes is a postdoctoral researcher in Oxford University’s Department of Oncology, and normally spends his time working on mathematical models of oxygen distribution in order to improve radiotherapy in the treatment of cancer.īut he is also a keen guitarist, and has been a session musician and member of a band in Dublin in the past. On a guitar, you can bend the strings to get the notes in between.

‘On a piano, you’ve got the 12 chromatic notes in a scale. ‘Very good guitarists will manipulate the strings to make the instrument sing,’ explains Dr Grimes. Now guitarist and physicist Dr David Robert Grimes has described the physics underlying these techniques in the journal PLOS ONE.

String bends, tapping, vibrato and whammy bars are all techniques that add to the distinctiveness of a lead guitarist’s sound, whether it’s Clapton, Hendrix, or BB King.

Good Thinking by David Robert Grimes