Abstract: An electric guitar has an electromagnetic resonating unit (3) which is arranged to resonate the strings (2) of the guitar, either individually or together. The resonance of each string is picked up by a pick-up unit (4), and the frequency of resonation of the string is detected and compared with a desired value. A tension adjusting unit (5) adjusts the tension in each string (2) until the frequency of resonance of the string correponds to the desired frequency, in order to tune the guitar to a desired tuning pattern. A control panel (6) on the body (1) of the guitar displays optional tuning patterns which may be selected by a user. Automatic tuning of the guitar may be achieved, without requiring the strings to be plucked manually.