Float Tunings Instead of Pitch
From the beginning, when Al Sanderson began measuring stretch numbers (inharmonicity) on pianos and creating a tuning based on that measurement (F Stretch Tuning) or those measurements (FAC), it’s been noticed that those measurements change. Back in the old ‘F Stretch tuning’ days, we might measure an F stretch number of 5.5 in the spring time, and then in the fall, on that same piano, measuring in exactly the same way, we may get a measurement of 6.0, or 6.3 or 4.9. The same thing happens with FAC tunings. We’ve all noticed that FAC numbers change from one tuning of the piano to the next tuning of that same piano. Everything else is equal, routines, everything. So why do we get different measurements on the same pianos?
Many have tried to answer that question and maybe some of them may even have the right answer, or at least think they do. I’m not really sure if I care at this point, the why of it. All I care about it how this will effect my tuning of that piano from one tuning to the next, and still have the piano end up at as close to exactly A440 as possible.
Let say, instead of creating a new FAC tuning each time, a memory tuning is used. Let’s say the FAC tuning from last time is stored in your SAT IV on page 250.
How can that tuning be used and be sure A4 will be @ exactly A440?
Or lets say your SAT IV’s memory if filled with memory tunings. Let say, there’s a tuning for a Yamaha C2 you like and want to use on every Yamaha C2 you come across, and it’s important to have each and every tuning as close to exactly A440 as possible. How can that be done, easily, quickly, and accurately?
Float the tuning not the pitch:
With a memory tuning, when the AccuTuner is tuning A4, the AccuTuner is listening to the 4th Partial. So, when A4 is tuned to A440 (tuned to the fundamental) we need to know where that piano’s 4th partial is so we can raise or lower the memory tuning to compensate for any difference between the memory tuning you want to use, and the piano being tuned.
Lets say we have a Yamaha C2 to tune and the memory tuning we want to use is on Page 375.
First, tune A4 to A440 using the fundamental (A4 @ 0.0). Once A4 is tuned as accurately as possible, set the SAT to listen to A4’s 4th partial (A6 @ 0.0). Now play A4 and use the cents buttons to stop the lights. Let’s say when the lights are stopped the display shows (A6 @ 9.0)
When A4 is tuned to A440, on this piano, the 4th partial is 9.0 c. sharp. That’s all we need to know. For this piano to be @ A440, the setting for A4 must be 9.0 c.
Now look at the setting for A4 on the memory tuning for this Yamaha C2 on Page 375. Lets say A4 on the memory tuning is 8.3 c. That’s a .7 c. difference.
If we just use the memory tuning with no correction, the piano will end up .7 c. flat (at the 4th partial). I know that’s not much, but since it’s so easy to fix, why not take a few seconds to fix it? It’s so easy.
To lower the tuning by .7 c., step up to C8 on the memory tuning and subtract .7 c. from the setting of C8 (if C8’s setting is 40, change that to 39.3). Now press (and hold) STO/Stretch and then press RST/MSR and then release both buttons. You will see the words ‘Partial Correction’ show up briefly in the display. That’s all there is to it.
Now step the SAT IV down to A4 and it should say 9.0 c. The memory tuning has just been lowered by .7 c., and using the newly adjusted memory tuning will now result in the piano being tuned to A440.
The stretch in the piano may be different from the memory tuning, but at least A4 will be @ A440.
This can be used for leaving pianos flat as well. The amount of the ‘Partial Correction’ can be +/- 200 c. For leaving pianos flat by 30 or 40 or 50 or 100 c. or even 200 c. flat, it’s not necessary to tune A4 and measure where it’s 4th P is. Just go to C8 and subtract the amount you want to leave the piano flat from the setting on C8. I.e. if the setting on C8 is 40 and you want to leave the piano 50 c. flat, subtract 50 c. from C8’s 40 and you’ll have -10 c. in the display. Press Sto/Stretch and RST/MSR and release and that’s it. Now that the tuning has been altered, the regular pitch raising feature can be used as normal.
Be aware that the tuning in your SAT IV was just raised of lowered, will stay that way in your SAT IV! It will not go back to it’s original A4 when the SAT is turned off. The tuning has been altered and will stay that way until you alter it again. If you want to put it back to where it was, just go back to C8 and add 50 c. to C8’s setting, press Sto/Stretch and RST/MSR.
However, that’s not all bad, because if memory tunings are being used often, they can be ‘floated’ this way, up or down as needed, and have every piano end up @ A440, or to the desired pitch.
If tuning to A442 is requested, just raise C8 by 8 c., press STO/STRETCH and RST/MSR and the piano will end up @ A442. The Pitch Raise Calculator will work as usual, and after the 8 c. pitch correction, the piano will end up @ A442.
Speaking of pitch raising and being a stickler for pitch, I’ve found the above routine useful when dealing with seasonal changes on pianos we tune.
Measuring A4’s 4th partial in March, and then again in September may result in 2 different numbers on the same piano. The differences between the two may not be much, but for the piano to end up @ A440, that difference needs to be corrected when using a memory tuning. Using the C8 Partial Correction feature is a really good way to do it.
This post has been about how to make sure the pianos end up @ A440 when using memory tunings. FAC tunings will often not put A4 exactly @ A440. So before measuring FAC numbers, tune A4 and measure where it’s 4th P is located so it can be checked against the FAC tuning after the FAC tuning has been stored to a page of memory. If a correction is needed, the Partial Correction is a great way to go.
I have many custom tunings for my customers’ pianos. Custom tunings I want to use again. I find using this routine can make the pitch corrections slightly easier and more accurate. Sometimes if the piano is a little sharp, A4’s 4th P will also be a little sharper than the A4 on the custom tuning. So I fix it, and the pitch correction for the piano is just slightly more mild, a little easier and more accurate. And of course the tuning ends up at A440.