SECTION II
TEMPERAMENT DESIGN
Meantone and well-tempering gradually evolved into the modern Equal Temperament, and just as with the earlier system, there was a proliferation of methods and schools, with a very conservative rate of progress.
The Yamaha or Japanese style adopted by the Sydney Conservatorium was developed in a research setting, unconstricted by loyalties and traditions. The academics who developed it looked at as many traditions as they could and developed the method using the best practices as the basis.
The Design of the temperament has these goals: Accuracy, Stability and Speed. They are inter-related. As an example, if a piano can be completely tuned in less than an hour, starting with the temperament in the middle and tuning to the top and then from the temperament towards the low end, then it can be expected to be stable.
This is because the iron-frame and cabinet take some time to react to the change in stress. The bass strings are positioned at an angle, with the lower part of the strings more towards the middle of the piano than the top part. Putting extra tension on the bass end can make the top end increase in tension by way of a see-saw effect centred aroung the middle.
  • A temperament obviously encompasses an octave. Any more than one octave introduces uncertainty, unnecessary retuning within the procedure,
  • On many pianos, the tenor strings change from plain-wire to copper-wound in the low tenor, and a large number make this change at F33, with E being the last copper-wound string. Copper-wound strings have a lower inharmonicity, and including a wound string in the temperament complicates tuning tht temperament.