A few ‘mini-targets’ are also mapped for using in the LC spreadsheet tuning calculation. These ‘mini-targets’ are notes D4 & E4, and D3 & E3.
Mapping and being able to include those mini targets for calculating the tuning is beneficial because it allows us to adjust the depth of the tuning curve in both the prime and sub prime octaves, and balancing the prime 5ths (A3/E4 & D4/A4), and the prime 4ths (A3/D4 & E4/A4).
This is also very useful in the sub prime octave where so many different scaling issues occur. Being able to tweak the sub prime tuning curve in the sub prime octave allow for very accurate mapping and establishment of the location of A2, D3 and E3.
One curve doesn’t fit all pianos. One might think that all we really need to know is where the A targets go, and the computer can easily fill in the blanks between the A’s. But that is not the case for all pianos. Sometimes the tweaks are very slight, but other times they can be quite significant – both in the prime and subprime octave. It just depends on the piano – the piano’s scaling in these two octaves.
Even if the overall prime octave width is perfect, the scaling contained within that octave will often result in a pair of ‘uneven’ or ‘unbalanced’ prime 5ths (A3/E4 & D4/A4) which means the prime 5ths are different widths. The prime 4ths will expose this unbalance.
Since the prime 4ths beat a little faster than the prime 5ths, this prime 5ths unevenness will more easily be heard in one of the prime 4ths (A3/D4 & E4/A4) beating a little faster than the other.
But once the 5ths are balanced, the 4ths clean up as well.
Mapping these mini-targets and incorporating their mapped values, into the LC spreadsheet, is a great tool for creating a very nice sounding prime octave tuning with the LC spreadsheet..
No other tuning system has this ability.