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 B2/C3 to G#2/A2.

A complete 2-Ooctave Temperament range (A2-A4) with all notes using the same partials (the 4th) and no partial changes is important for accurate aural checks in the temperament.   This procedure will lower the FAC’s tenor partial change from B2/C3 to G#2/A2.

Accurate aural checks are important for making sure the stretch in the midrange is a good fit for the piano.

This procedure will also give some guidelines for the width of the  A2/A4 4:1 (double) octave, and how DOB can be used to expand or contract the A2/A4 4:1’s width.

This procedure uses a 7-note ‘sequence’ programed into the SAT IV.   Using a programmed sequence keeps the technician from having to scroll up and down thru the notes to get to the next note in the tuning sequence.   If the tuning sequence is stored into the SAT, advancing to the next tuning note in the sequence is simply a matter of pressing the note up button.

This sequence speeds up the tuning of the 7 reference notes (A4, A3, D4, E4, D3, E3 and A2).  This makes finding the best width for the pianos midrange faster and easier.  This procedure will describe how to use a ‘sequence’.

The treble stretch is addressed as well and will give a guideline for the amount of DOB to use in the treble.

Before measuring the FAC numbers, tune A4 to A440 (A4 @ 0.0).   Then set the SAT to (A6 @ 0.0) play A4 and stop the lights with the cents buttons.   That is the setting for A4. Make note of this A4 setting, it will be needed later!

1. Measure and Store FAC as usual using .8 A Multiplier Default.

 2. Lower the tenor partial change to G#2/A2.
Once the tenor partial change has been lowered, it is easy to see the width of the A2/A4 double octave.

3. Using the Partial Change Corrector (PCC), correct the two treble partial changes.

Start with B5/C6 and then do B4/C5.

4.  After the two treble partial change corrections have been made, look at the setting for A4, and compare it to the setting you made not of earlier that you know is the right setting for A4.

Using PCC on the partial changes above A4 effects the locations of all the notes below the partial changes – including A4.

5. Correcting A4

Go to C8 and add or subtract that difference to the setting of C8 and press STR + MSR.

For instance:   If the original setting for A4 is 9.0, but after the partial change corrections have been made, A4 is 11.0, the difference between the two A settings is 2.0 c.
Subtract the 2.0 c. difference from C8 and press STR + MSR.   (If C8 is 36 c., lower it by 2.0 c. so that C8 is now 34 c.)   This will lower the whole tuning by 2.0 c. and put A4 back to 9.0 c.

All these PCC changes are stored onto the page in the SAT. If you turn the SAT off and then on again, and then go back to that page, the tuning will be exactly as you left it, will all the partial changes corrected.

At this point, if you want to save this tuning onto a different page in your SAT, use the Copy and Paste buttons to copy it to a different page. (The Copy and Paste feature only works in the lower memory of the SAT IV’s pages 1 – 122.)

6. If you want to add a name to this tuning, here are the instruction from the SAT IV Instruction Manual:

With a page of memory selected, hold down the DISPLAY key until the cursor starts to blink under the
first character. The NOTE up button will move the cursor to the right, NOTE down will move the cursor to
the left. The CENTS up button will move up the character sets, CENTS down button moves down the
character set. The PAGE button will move in jumps from lower case alphabet to upper case alphabet, to
the special characters. Once the desired character is displayed use the NOTE button to move to the
next location to select a character. Once the desired information is in the header, the SHIFT button will
store the new header information.


The rest of these tweaks will NOT be stored with the tuning and must be done ‘on the fly’.

Working with the A2-A4 midrange to find a good fit for the piano.

Since the FAC’s default partial change location has been moved from B2/C3 to G#2/A2, there is now a complete Two-Octave temperament range with all notes using the same partials.

{In this tenor area, even if the partial change has been moved and corrected, sometimes it needs to be moved lower.   This has to do with the ‘reliability’ of the partials on the bass strings.   When trying to find a smooth sounding tuning in this area, the parallel is finding a smooth ‘set of numbers’ for this area.

Whatever partial is used, a smooth set of numbers is the goal.

On well scaled pianos – pianos with a well designed and well made set of wound strings, the 3rd, 4th, or 6th partials can probably be used without any problem.

But on the shorter scales, with their poorer scaling, poorly designed and/or poorly made wound strings, partial selection can can make a big difference.

On those pianos, the partials on each string can be quite different from their adjacent notes.   And the higher the partial the more ‘different’ they can be.   This is why using a ‘lower’ partial can be and often is more ‘reliable’ than using one of the higher partials for tuning.  

When a tuning uses a smooth set of numbers and a lower partial, even though the higher upper partials may jump around a lot, they will not cause anywhere near the problems created when trying to use a smooth set of numbers and one of the higher partials for tuning.   

Sometimes the higher partials are so inconsistent that the lower partials end up being all over the place as well.   This can make aural checks confusing and inconsistent.   Sometimes the scaling or the wound strings are so bad that when using the 6th partials and a smooth set of numbers around A2, the 3rds, 6th, 10ths, 5ths, octaves, sound awful.   But when the 4th partials were used to tune this same area on this same piano during the same tuning session, the 3rds, 6ths, 10ths, 5ths will sound much better. 

Just be aware if your system uses partials higher than the 4th for bass tuning.  At least FAC tunings only have one partial change in the bass area: either B2/C3 the default, or G#2/A2 if you moved it.   

After lowering and correcting the tenor partial change, if you still hear issues on down into that 2nd octave, unreliable 6th partials is the probably cause.  Don’t be afraid to move the partial change even lower, maybe down to E2/F2?   This won’t be necessary on every piano of course, but if you’re listening and paying attention, one of these days you’ll come upon a piano that will need this type of special attention.   But now you know what you can do to make it work.

You’ll have to create your own little tuning curve and store it into the SAT with all those notes using the 4th partials.   It’s not as difficult as it sounds.   Most of the time, technicians end up tuning the bass aurally, and that’s fine, but now that you know what’s going on down there, you have another option to compliment your aural skills.

7. A2:

Look at the setting for A2 now on the FAC tuning.

This is taken from Al Sanderson’s ‘Instructions for Direct Interval Tuning of the Two-Octave Temperament’:

“Step 2. Tune A2 from A3 as a 3-6 octave 1 cent wide. Check the A2-A4 double octave, and if it is more
than 4 cents wide, divide the excess by three and narrow both octaves by this amount. (E.g., if double
octave is 5.5 cents wide, 5.5-4 is 1.5, divide by 3, and narrow both octaves .5 cent.)”

So if A2 it is lower than -4.0, A2 may need to be raised.   DOB can be used for this.
At A2, .1 DOB will move A2 by .4 c.

8. Before going any further, tune A2 and A4 and see how the double octave sounds.

You might like it where it is.  Use the midrange sequence and tune the rest of the reference notes: A4, A3, D4, E4, D3, E3, and A2 to the tweaked FAC tuning.
Listen to see if the tuning  sounds like a good fit for the piano.

Here are a few guidelines: 
My average A2 setting is generally around -2.7 c. to  – 3.0 c.   But that’s not an absolute by any means.   That’s just my average.

I have had to place A2 much lower @ -5.8 c.   But that was an exception.   I’ve also placed A2 @ -1.9 c. as well.   A2’s location depends on the piano, just like all the rest.

But try a A2-A4 4:1 width of between -2.5 and -3.0 c. and work from there.

Lean on the A2/E3 5th and the highest 4th (E4/A4). Try to find a good combination for those intervals, and then check the rest of the intervals created by the reference notes.

With a little experimenting, experience and listening, a good width for the midrange section (A2-A4) can be found.   Some pianos make it easier than others, but you should soon be able to find a nice compromise fit for the piano.

9.  Make a note of the DOB setting – and the setting for A2 – you think fits this midrange area the best.

10. Check the tenor partial change again.

Now that the midrange has been more finely adjusted, check the tenor partial change again.
If another PCC correction is needed at this point, it should be minimal.   After pressing STO + MSR, the DOB will still be in the SAT, and the settings for both A2 and G#2 will be right where you want them.    The PCC works even with a DOB setting being used!

The tweaks for the lower half of the piano are now all done.

At this point, I’d suggest keeping it simple and use a single DOB for the lower half – the same DOB used for the midrange will probably work fine  for the A0 – A2 range.

Before veering off too far on your own, tune 50 or so pianos using this procedure first.

Only after using it on a number of different pianos, will you have a good idea as to how this sounds compared to your previous methods.   Once you have done tis a few times, it will go quickly, and you’ll hear the improvement in your work.

I’ve given you some guidelines here that will get you started, but as you gain some experience and speed, now that you have this new knowledge, go ahead and try different things and do your own listening.   That’s the fun part anyway.
I enjoy making the decisions, deciding what I think sounds good, and how to get there.    The actual SAT button pushing will soon become 2nd nature.  It’s the listening that takes time.

11. Write down midrange DOB setting!

Make all the measurements, all the aural checks, and make all the decisions before doing the tuning.

Now that all the partial change corrections and the resetting of A4 is done and stored with the tuning onto a page of memory, the only other written notes that need to be taken are the DOB settings for both the Bass (A0-A4) and the Treble (A#4-C8).    Those DOB settings will often be different.  Make sure to change them above/below A4 so the correct one is used for the bass and the correct one is used for the treble.


Finding a good DOB setting for the Treble:

Treble tuning is a lot more subjective than we might think.   But for this exercise a fairly safe and good sounding setting for A6 will be about 1.5 – 2.0 higher than the setting on A4.   This results in an A4/A6 double octave about 1.5 – 2.0 c. wide..

Sometimes A6 may need to be a little higher or lower, but this is a good starting width for that double octave on many pianos.

For example:   If A4 on the tuning is 9.0 c., and A6 is is 9.8,  some DOB is needed to move A6 from 9.8 up to around 10.6.

Each .1 DOB will raise A6 by .4 c..      10.6 – 9.8 =  .8 c.   A DOB amount of .2 is needed to raise A6 up to 10.6 c.

After deciding on a DOB for the treble (A6), tune A5 and then D5 and E5.   First listen to the D5/A5 5th.   If it needs a little more stretch, add another .1 DOB and re-tune A5 and D5 and give it another listen.

The upper 5th in that octave will let you know fairly easily and quickly if A5 is sharp enough.  Then listen to the lower 5th (A4/E5).  It will hopefully confirm. But if you think either of those 5ths need to be a little cleaner add another bit of DOB and retune.

(Just be aware that .1 DOB adjusts A5 by .2 whereas each .1 DOB adjusts A6 by .4 c.   The goal is to use a single DOB setting for the treble by finding a good sounding compromise for both A5 and A6 using a single DOB setting.   So as you adjust the DOB @ A5, keep an eye on what is being done at the A6 position.)

Once happy with A5, tune A6, D6, and E6 using the same DOB amount as when tuning A5!!

Now that there are no partial change errors – since you corrected them earlier, you should be able to find a good DOB setting that will sound nice for both A5 and A6.

Now you’re ready to tune the piano.

All the partial changes are correct, no errors there, A4 is correct and the tuning will end up @ A440, the Midrange will be a good fit and the treble stretch is a good fit for the piano.

Since your DOB settings are written down, make sure to use the right DOB when tuning the Bass, and remember to change it @ A4 to the Treble DOB setting.

DOB settings can’t be stored to the tuning but the PCC adjustments are.      If this piano is one you tune often, all you will really need to keep track of is where the tuning is in your SAT (Naming will help with that) and the DOB settings you use for the bass and the treble.    This is something you will only need to do once on each piano.

I’ll put in a pitch here for suggesting you look into getting set up for using the Inventronics Piano Manager Software and your PC.  Since the standard SAT IV has 400 pages, and the SAT IV “980” has 980 pages, it might be handy for you to start using, if you aren’t already, the Piano Manager Software with your SAT.   With it, you can store these pianos to the upper memory.   Doing so will allow you to store hundreds of your favorite customers pianos in your SAT.  With Piano Manager, tunings can be named, arranged, headers can be printed, and backups can be made.   There are lots of things Piano Manager can be used for that can make this type of upper level tuning work more repeatable.