The A4 Numbers
The “A4 numbers” are the locations of the 2nd, 4th, and 8th partials of A4 when A4 is tuned to A440 (1st Partial).
Robert Conrad, Registered Piano Tuner/Technician, Tucson, AZ
The “A4 numbers” are the locations of the 2nd, 4th, and 8th partials of A4 when A4 is tuned to A440 (1st Partial).
There are a number of ways, when using an AccuTuner, to tune to non standard pitch. PCC is one of the easiest and most versatile. When PCC is used for tuning to non standard pitch, make note of the PCC adjustment so it can be reversed when the tuning is finished.
Using a sequence is a great way to quickly tune and make aural checks before committing to the complete tuning. (Contains button pressing video).
All computerized tunings have partial changes and those partial changes may contain an error. Correcting these errors can improve the sound of the tuning. This procedure will show how to correct the three FAC partial changes when using an AccuTuner SAT IV. But before correcting the partial changes, consider lowering the tenor partial change from…
This Partial Change Correction (PCC) feature is relatively new to the SAT IV’s programming. So if your SAT doesn’t seem to be responding to the STO + MSR command it’s program may need to be updated. Being able to correct partial changes is unique to the AccuTuner. An FAC tuning has fewer partial changes (3) than any other tuning system, and yet it is the only device capable of correcting them. (Contains button pressing video).
This post is part of a series on working with an FAC tuning. There are a number of tweaks that can be done to further fit an FAC tuning to the piano, before changing the F number.
Programming a custom over pull is so easy it’s not worth making a video of it. The custom over pull is ‘activated’ just like the regular pitch raise feature, but instead of rolling off onto the BlueShift, after MSR stops the lights, roll off onto the Green Shift. Rolling off on to the GREEN shift activates he Custom Over Pull and uses the amounts stored on Page 123.
Even though the width of the prime octave’s may be perfect, the piano’s scaling within that octave often results in a pair of ‘unbalanced’ prime 5ths: (A3/E4 & D4/A4)
DOB allows us to easily stretch or contract a template or tuning stored in the SAT.
The ‘4th A4 Number’ is the width of the prime’s 2:1 after it has been tuned as a pure 4:2. Knowing this 4th A4 number from the very beginning lets me know immediately what I’m going to be dealing with on that particular piano.
Balancing the prime 5ths involves tweaking the shape of the prime octave ‘curve’ by slightly raising or lowering the mid point of the prime octave curve, while leaving A3 and A4 unmoved. Since using D#4 is not practical to be used as a mapping note, D4 and E4 are used instead. D#4 can easily be placed between the settings of D4 and E4. Being able to apply this tweak to the tuning is a unique feature of this system of mapping with templates and then using the LC Spreadsheet to create the tuning.
The prime 5ths are used to determine the best prime octave width for the particular piano being mapped and eventually tuned. When the widths of the prime 5ths are added together, when that total is -3.0, the prime octave width is about right.
For years and years, I have used the triple octave location for A7. It’s not a bad spot either. But since March 2020, I’ve begun tuning A7 higher than that. I’ve started using the triple octave +5th as a starting point for my A7 location.
Once the location for A2 is known, mapping A1 is very straightforward. A good location for A1 is as a 6:3 octave (from A1), 3.0 cents wide.
Mapping A0 can be done any number of ways. It can be mapped however you like, but just like A1, once you have it where you want it, it’s location must be measured using it’s 4th partial, since the LC Spreadsheet uses the 4th partials for A0 – A4.
When talking or writing a lot about tuning, descriptive shortcuts are inevitable. Referring to the A3/A4 octave as the “Prime” octave came about as one of those shortcuts. Soon after that, the term ‘Sub-Prime’ was used to describe or identify the octave below the prime octave. The A2-A3 octave.
The new Sanderson Accu-Tuner Max “980” has 980 pages of memory – more than double the number of available pages of the standard SAT IV.
Tweaking the treble stretch in an FAC tuning is a great way to ‘customize’ a tuning.
For those without Accu-Tuners, or for those with older Accu-Tuners without the Piano Librarian software, the download package may still be of interest. In addition to the tuning files in the .sat format, the download package also contains the templates in the Excel Spreadsheet format, for opening with Excel or any other spreadsheet program.
There are a number of different ‘types’ of vertical pianos, just like there are a number of different sized grand pianos. Knowing the type of piano helps me get a better idea as to what might be involved in servicing it.
Different situations, different pianists, and different pianos require different maintenance schedules.
It’s impossible to talk about pianos, piano tuning, and piano care without talking about humidity.
To make them easily available, these download tunings are in both .SAT and Excel file formats. Also included is a Header Sheet in Excel form, which contains the piano mfg, and model, and the settings for each ‘A’ on the tuning.