What a way to start a controversy among tuners. Ask this question at a piano tuner’s convention and step back and watch the fireworks.
The reason that this is a heated topic is because both sides have strong opinions, and both sides are right. Both aural and electronic tuners have the potential to produce perfect tunings.
An aural tuner will use their ears to listen to the beats produced by intervals at the piano, and tune those intervals so that they have the desired relationship of beat speeds between intervals.
(Click Here to watch my video lesson on Beats.)
While a good electronic tuner will also use their ears, they also use an electronic tuning device, sometimes called an ETD, to help them decide where a note should be tuned.
Aural tuners constantly listen to each interval on the piano many times and are always trying to find the right compromise between intervals so the piano as a whole sounds the best it can sound.
One reason for this compromise is due to inharmonicity. Inharmonicity describes the fact that higher partials or overtones in a string are sharper than ideal. This means higher notes must be tuned sharper than the mathematical ideal, and lower notes must be tuned flatter than the mathematical ideal, if the octaves are going to sound good. The result is what tuners call a “stretched” octave, and also results in a piano that has the treble notes sharp from ideal, and the bass notes flat from ideal. And this amount of “stretch” is different for different pianos!
This is why a guitar tuner will cost $35, and an ETD will start at $400!
An ETD will “approximate” the stretch curve by first listening to four to six notes on the piano. (Some listen “on the fly” to each note but then are changing the stretch curve for notes that have already been tuned. If the tuner has the discipline to go over the piano many times, these ETD’s can produce a much more precise tuning than the rest.)
The result is that the ETD is always “approximating” the actual stretch curve that is best for the piano in question.
So, to answer to the question in the title, we need to understand that aural tuners are at different levels of ability, and ETD’s give approximations of the ideal stretch curve.
See the diagram below to understand how aural and ETD tuners can achieve varying levels of precision.
In this diagram, the precision of the aural and ETD tuner is shown by circles. The ideal tuning is the bull’s eye. It should be noted that the ETD has a more consistent precision, while there is some variability to the aural tuner’s precision, depending on ambient noise, mood, etc.
The ETD’s accuracy, or centre of precision, is shown “off centre”, to illustrate its approximation characteristics.
The left target shows the precision of a beginning or intermediate tuner. The ETD circle is much smaller and the relationship of the circles illustrates that the ETD is more likely to produce a tuning that is better than that of the aural tuner.
The right target shows the precision of an expert aural tuner. The circle is much smaller than that of the ETD and the result is that the expert aural tuner’s accuracy is more likely to be better than that of the ETD.
It should be noted that with this model, there is always the possibility that the beginning or intermediate tuner will have a higher precision than the ETD on a case by case basis, and the ETD could have a higher precision than the expert aural tuner, on a case by case basis, it is just not as likely.
When looking at this question using this target model, the answer to the above question is not so easy to conclude. There are tendencies toward one, given certain circumstances that deal mainly with the precision of the particular aural tuner in question.
In the end, the tuner has to tune many pianos if they are to have a successful business, so they have to be happy with the choice they make; aural or ETD. Also, it has to fit with their own personality and aptitude, and they and their customers have to be satisfied with the result.
