Lowering the FAC Tenor Partial Change: The “Why”
Wherever there is a partial change, there is potential for an error at that partial change.
For a smoother tuning in the A2-A4 range for tuning a 2-Octave Temperament, all the notes within that range should use the same partial. This eliminates any possibility of a partial change error in that A2-A4 range.
Most tuning systems have at least one partial change below A4. Some systems have 2 or even 3! In order for aural checks to be accurate, errors at the partial changes need to be corrected.
An FAC tuning has one partial change in the A2-A4 range. The tenor partial change in an FAC tuning is between B2 and C3. An FAC tuning uses the 4th partials from C3 to B4.
In order to get a full Two Octave Temperament range using the same 4th partials, all that is needed is to lower it’s B2/C3 partial change down to G#2/A2.
Once we’ve lowered the tenor partial change location from B2/C3 down to G#2/A2, there will be a complete 2-Octave range of notes from A2-A4 all using their 4th partials.
This improves the reliability and accuracy of our aural checks because they will be free of any issues caused by different partials being used and/or a partial change error.
It is up to the technician to know where the partial changes are in whatever system being used, and how to fix them when they cause their noticeable ‘hiccups’ in the tuning.
When using an AccuTuner to do an FAC tuning, its easy to move the tenor partial change a few notes lower.
Another advantage to lowering the tenor partial change is, that on all but the longer scale pianos, lowering the partial change down to G#2/A2 places the tenor partial change onto the bass bridge.
This is an advantage on the ’26 bass’ grands whose lowest note on the long bridge is B2 and the highest note on the bass bridge is A#2.
Here is what we are doing in graph form:
First of all, here is an FAC tuning with the 3 partial changes circled in red.
The partial change we are going to lower is of course the one in the tenor (B2/C3).
(Click on graph to enlarge.)
Here’s how it will look when done:
(The vertical lines in these graphs are the ‘C’s.)
(Click on graph to enlarge.)
Here are a few blowups’ of what’s done when lowering the partial change:
(Click on graph to enlarge.)
This next graph is a 10 – 9 – 8 FAC tuning but with the .8 multiplier default. Instead of A2 @-4.5, the .8 multiplier puts A2 @ -3.7 c.
Here is a video on how to lower the tenor partial change:
Bob, The piano sounds beautiful! I did some recording of it tonight. Suzanne
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Hi Bob. . . Yamaha sounds fantastic! Great Job! Thanks so much, Carol & Wayne
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Bob, my piano sounds much better! I'm impressed with your ear and your knowledge.
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dear bob, just wanting to tell you, piano sounded great. yours is the best tuning I’ve had in years. let’s set up another time for some more magic.
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Bob, I just wanted to tell you how wonderful the tuning job was, I never heard the piano sound better, either I am getting older and cannot hear or you are getting better, I think it is the latter. You...
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. . . the piano sounds great!
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Thank you, Bob, for the fabulous job you did with our piano. It sounds wonderful! Regards, Meryl Wade
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Hi Bob. Thank you so much for the exceptional job you did tuning my husband’s old piano back on February 13th. He was thrilled and it sounds just gorgeous now! Best, Janet Mabon
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Thank you so much, Robert, for the wonderful job you did tuning my very old upright grand piano. Stopped playing long enough to write this review. You worked a miracle and what a thrill to hear those rich bass sounds...
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Just a note regarding my Schimmell grand piano. It sounds fantastic and bell like with very pure tone just like when I bought it. I played it quite a bit this weekend and as you noted one hears every note....
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Good morning Bob…….Thank you for sending the excellent report. It is well written, thorough and….well, perfect! You have mucho expertise when it comes to pianos…..we were lucky to have such a person….
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My Hamilton console piano had not been tuned for over 6 years and moved from humid South Carolina to dry Tucson. So I called a friend, who plays the contemporary music at our church, and he immediately recommended Bob Conrad....
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Bob, your class at the Convention was amazing. Now I have a thirst for more. I am interested in your tunings for my SATIV.
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Bob is a great tuner. He has tuned not only my studio piano but those of my my voice and piano students. He’s more than just a tuner, he’s a fine technician as well. He’s a fine musician too, possessing...
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Bob did the best job possible tuning my piano which I had neglected for five years I am ashamed to admit. Thanks Bob it sounds awesome....
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