As temperatures in Britain head towards record heights, the same phenomenon which has caused the railway tracks to behave like cooked spaghetti, has forced me to comment on the use of electronic tuners and other aids to tuning.

These devices are fine for getting a guitar in tune with itself, for solo playing or studio work. However, if you join in a session, the guitar must be tuned to the instrument(s) which cannot be tuned; mainly fixed-reed instruments such as harmonicas and melodeons, and wind instruments such as flutes or tin whistles.

Where you are playing with such instruments, the drill is to tune to the natural frequency of the offending squeeze box, often D. Once the D string is tuned to that instrument, I generally tune using harmonics which are easier to hear in noisy pubs:

6th (E) string 5th fret harmonic to 5th (A) string 7th fret harmonic
5th (A) string 5th fret harmonic to 4th (D) string 7th fret harmonic
4th (D) string 5th fret harmonic to 3rd (G) string 7th fret harmonic
6th (E) string 5th fret harmonic to open 1st (E) string
2nd (B) string 5th fret harmonic to 1st (E) string 7th fret harmonic
Finally, 3rd (G) string 4th fret (not harmonic) to open 2nd (B) string, as a check

The other night, with the temperature recorded behind the bar as 84 degrees Fahrenheit (even with several fans blowing there, which meant the rest of the pub must have been a lot hotter), a lot of instruments definitely didn't sound their usual selves. In such cases, you will have to do it by ear, rather than with tuners.