First, identify one string from one note to tune. Most notes except the very lowest ones will have two or three strings per note. My little piano only has two in the this octave, but it's more common to have three. Press the key, see which hammer moves, then trace the string up to its corresponding pin.
After selecting the string to tune first, mute the other string(s) in the set for that note. Wedge a rubber mute between the string to be muted and the soundboard or the next string over.
Tune the unmuted string using the electronic tuner. Silence the room; any extraneous note, even a motor, will be picked up by the electronic tuner. With one hand on the lever, one finger on the key, and one eye on the electronic tuner, strike a key firmly. Move the lever very, very slightly while striking the key firmly over and over. Turn the pin clockwise to raise the pitch, counter-clockwise to lower it. (Righty tighty, lefty loosey!) I want the needle on the tuner to be as close to the middle as possible.
Tune the other strings in the note; this is tuning the unisons. Remove the mute from one of the other strings in the set for that note. Put aside the electronic tuner, and use your ear to match the untuned string to the string you just tuned. Repeat for the third string, if necessary; unmute all three, so that the third string matches the first two. Why no electronic tuner? Because hearing the match is more accurate than trying to adjust that pesky bouncing needle tuner.
Repeat Tuning the Temperament steps for entire middle octave.
Important considerations about this process:
- Minimal pin movement is important; too much wiggling can loosen the pin so that it will not hold. Loose pins need professional repair. Do not overwork the pin! It's also possible to break a string. It can happen if over-tightened, but even professionals break a string on occasion. It is a common repair, but beyond this tutorial. There are books on piano repair, or call a pro.
- It's difficult to get the needle dead on. I usually err a little to the sharp if in doubt, as my piano usually goes flat. Alternatively, the Korg can play the tone for you, and you can match by ear.
- A professional tuner will tune the upper octaves increasingly sharp and lower octaves increasingly flat. This is known as stretching the octaves, a sound more pleasing to the ear than tuning to equal temperament, which would ideally follow a pure mathematical progression. This is because error is introduced by the physical differences between strings (e.g., the fat lower strings react differently to being struck than the thin, short, upper strings.) The best stretch is a judgement call determined by a professional tuner's experience. If we were to tune the entire piano with a simple chromatic tuner the result would be poor. The more we tune by ear, the closer we can approximate what a professional does.
