The Main “A” Targets and the Mini-Targets
The ‘A’ targets are the ‘main’ targets and include every A on the piano – including A0 and A7.
The ‘mini’ targets are the D’s and E’s in the 3rd and 4th octaves.
The LC spreadsheet uses the locations of target notes to create the tuning. LC requires the ‘main’ target notes be entered.
The ‘mini’ targets are used to refine the ‘shape’ of the the curve within the prime and sub prime octaves.
Prime Octave Mini Targets: Even though the width of the prime octave’s may be perfect, the piano’s scaling within that octave often results in ‘unbalanced’ pair of prime 5ths (A3/E4 & D4/A4).
This can be easily determined by simply tuning tuning A3, D4, E4, and A4 to the FAC tuning or whatever other tuning (template) being used and then measuring the prime 5ths. If the widths of those prime 5ths are different, they will be beating unevenly and therefore need to be balanced for the most harmonious outcome. And unbalanced pair of prime 5ths, can often more easily be heard in the resultant prime 4ths (A3/D4 & E4/A4). Since the prime 4ths beat faster than the prime 5ths, the unbalance is easier to hear. The resultant prime 4ths really expose the unbalance.
Here is where the ‘mini’ targets are used. Once the location of the mid point in that prime octave has been determined, the LC spreadsheet will use those ‘mini’ target correct balanced location when it creates the tuning.
Establishing the mini target locations is done during mapping of the prime octave. Templates are used for this.
Being able to tailor the shape of the curve within the prime octave allows us to more accurately fit the curve of the tuning to the scaling of the piano.
Mini Targets within the Sub-prime Octave:
In the Sub-Prime octave the mini targets of D3 and E3 are not used for ‘balancing’ the sub-prime 5ths. Due to all the scaling issues that occur within that A2-A3 range, the mini targets in this area are used for adjusting the shape of the curve to accurately fit the scaling in that sub-prime octave.
In this are of the piano the pair of sub prime 5ths (A2/E3 and D3/A3) are rarely the same size. Due to the stretching lower that starts in this A3/A2 range, the lower sub prime 5th will generally be less narrow than the upper sub prime 5th.
Using the mini targets in the sub prime will again allow for more accurate ‘shaping’ of the tuning curve in this area. And as in the prime octave, once the settings for D3 and E3 are known, they are then incorporated into the tuning that will be created by the LC Spreadsheet.
As an example, sometimes a piano’s D3 is a wound bichord and E3 is a plain wire trichord. Using these sub-prime as well as the prime octave mini targets really allow for a much better fitting tuning that will be created by the LC spreadsheet.
Being able to map both main and mini targets in both the prime and sub-prime octaves, gives us the capability to create a super custom midrange tuning for any piano.
Of course there are exceptions, but they are rare. But I must mention one here as an aside. A few years ago I was visiting another tuner/technician in England who owned a 3 Bridge Steinway Model A. I believe the break going from plain wire trichords to the top note on that little tenor bridge wth it’s wound trichords was between C#3 and D3? Is that right? I think it is. I think C#3 was the top note on that little tenor bridge and it was a wound trichord. Terrible terrible terrible scale as anyone knows who’s tuned one knows.
But since our mini targets are D3 and E3, the issue with the transition going from D3 to C#3 didn’t get picked up in the mapping. And of course A2 was on the bass bridge on that piano.
But as soon as he started tuning and got to that C#3, that C#3 didn’t wok with anything above it! It was really awful. The C#3/C#4 octave was bad, the C#3/G#3 5th was terrible, the C#3/E#3 3rd was terrible too! Nothing worked.
We eventually used our ears as well as some technical information to get a bearable compromise in there, but it took some fairly thoughtful compromising. What made me happy was that we were able to make it work OK and only changed 4 notes or so: A#2, B2, C3 and C#3 I think they were. We didn’t want to change any more than we absolutely had to. The rest of the tuning above that break sounded great and we didn’t want to change any of that part.
So just make sure to check things in this area. I’m sure there is not a tuning system alive that could have covered that break out of the can. Aural only tuning included! I too, doubt there is another system out there that could have made it sound as OK as we did by only moving 4 notes either.
These kind of things are great learning experiences. I had one of these 3 Bridge Steinway A’s in a church of mine when I was in Kansas City and I never could get it to sound good. It’s just a terrible scale. Steinway’s worst.