@Jason KanterThanks for posting this. There are some similarities in the process I've come to use, and I have already added some of your ideas.
First, some thoughts on the 3-part tuning itself, which I've been using for about 3 months.
-It's
far and away better than the old 2-part tuning function, designed for poorly scaled pianos. I would hardly ever use that because it only helped a fraction of the time, and even that was hard to predict. And the user didn't have as much control.
-I have interested in trying a Perfect 12th-based tuning style for a couple years now, and Tunelab finally supports it with the 3-part function. Now that I'm several dozen tunings in, I have found it better to use a single-octave style for the bass, as 3:1 tends to make it much too compressed. I use 10:5 as a default for grands and 6:3 for uprights, but I always try a couple options before tuning a piano I haven't done before (more on that below). But in the midrange and treble, I really like how well a 3:1 tuning blends the registers on almost all pianos. To my ears it yields very balanced sound, whereas the original TL tunings based on 6:3 / 4:1 (or similar) would often sound to me more compartmentalized. Think of the conductor from Disney's Fantasia, "Here's the bass, bold yet smooth. Here's the tenor, it's sweet and even. There's a bit of a break between them, but we don't talk about that. And now here's the treble, it's where we hear the Railsback curve go up like thiiiis."
-My wishlist for Tunelab would be to support the selection of where the midrange ends as well as where it starts, along with choosing two different interval types, and a percentage balance between them, for each of the three sections.
Something like this: (I'm imagining a medium-sized American upright, where one interval type in each section isn't quite right. I haven't actually tried this particular style, but you get the idea)
Bass: 8:2 / 6:3 @ 60/40%
Midrange: 4:2 / 3:1 @ 50/50%, from E3 to C5
Treble: 4:1 / 3:1 @ 50/50%
(FWIW, Verituner was doing this 15 years ago. But when my VT100 box died I couldn't afford to replace it, and started using Tunelab in the meantime. I like many things about both of them.)
Jason, your protocol brings me to questions I've had and maybe you or someone here can answer
-Where is the sweet spot for the number and selection of Inharmonicity measurements?
I have been doing A0-A6 for a while, but I'm not satisfied that's the best thing. I like limiting the number of measurements, and using A's (TL measures C's by default, I think, but somehow I feel less like a dumb American by using A's, and it gives my one more mostly usable note to sample). However A0 and A6 can be unreliable notes to measure, depending on how the string or hammer responds. So occasionally I will delete the IH constants on one or both of them, or even change them entirely to a value I think will put the extremes of the piano roughly where I want them, depending on where A1 or A5 are. When A0 is much more than 0.800 it seems to shoot down into the basement unnecessarily, and A6 seems to need to be at somewhere between 3.5 and 6.0. For context, I like to avoid extreme offsets, like C8 higher than +45c (or lower than +30c), and A0 at P6 much lower than -20c to -22c. If TL gives me something outside of that, it tells me that either a better interval choice might be available, or that there's no way the last few notes will sound good anyway, and it might be just as well to have more reasonable string tension across those octaves.
So, lately I've been experimenting with other arrangements of sample notes, such as C1, A1, F2, C3, A3, F4, C5, A5, F6 (or substitute E's, but I'm Jazz guy, so I like Fmajor). This satisfies my irrational need for a musical arrangement of sample notes, and is a middle ground between sampling 7 notes (A's only), and 12+ notes (C and F# in octaves 1-6, plus stringing breaks). Also it seems the lowest sample note is "low enough", C3 is right over the tenor break on a lot of grands, and F6 is high enough to have a significant effect on the high treble but is low enough to be a reliable sample note. I prefer to sample the same notes on all pianos, or as many as possible, because I find it very informative to compare this information and try to synthesize it with what I am hearing.
Other questions I have include, "how close to the break do need to measure to get a usable interpetation of the IH jump" and "how accurate does a pitch raise really need to be." Those are probably best done another time.
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Gavin McGraw, RPT
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Original Message:
Sent: 12-07-2019 17:06
From: Jason Kanter
Subject: TuneLab's 3-Part Tuning (rave)
I started using TuneLab when it had 97 in its name. There's a new update, available now on some but not all platforms, but I'm a beta tester and it's just a sneeze away from being here, and I'm pretty excited about it.
Until this upgrade, TuneLab essentially worked like this:
- Take measurements of the piano, by default all the Cs from C1 to C6.
- Choose a curve by specifying the bass interval and the treble interval, defaulting to 6:3 in the bass and 4:1 in the treble. Of course there's a lot more, but that was the basis for the math.
The new version makes dramatic improvements in both the measurement process and the curve.
Before, the measuring process followed exactly the predetermined targets - C1, C2, C3 etc. Now, with "auto all", you can play any note, Tunelab recognizes it and goes there, and you can measure. This means you can easily measure the notes just above and below the tenor break, which are often different from piano to piano. And there is always a jump in the inharmonicity constant at the point where the plain wire strings begin. Now you can measure that jump and include it in your tuning calculation, instead of being smoothed out between the Cs.
This works hand-in-hand with the other major leap forward, which is called "3-part tuning." Before, the definition of your tuning was based on the bass interval, measured from A0 upward, and the treble interval, measured from C8 downward. Inbetween, the two ratios morphed into each other because math. However, there was no way to directly control anything about the relationships in the middle of the keyboard. (Well, you could force a curve to meet certain targets, but that's a different conversation.) Now, there is 3-part Tuning, which uses the same bass and treble setting PLUS a third "middle interval" setting, so you could for example set D3-A4 to be 3:1, thereby taking control of the center of the tuning and working outward, and using the better measurements of jumps in inharmonicity, and I'm telling you these tunings are good and they handle the break beautifully, especially when you set the middle 3:1 interval to start with the first plain-wire strings.
I find I'm spending twice as much time in overpull and half the time in fine tuning, overpull putting it so close.
So here's how it works. (You have to have a version that includes "3-part tuning" in the tuning curve settings.):
Prepare TuneLab's default settings:
- In the tuning curve window, set as default: 3-part tuning, with Bass Interval 8:2, Middle Interval 3:1 (D3-A4), and Treble Interval 3:1. (The Middle Interval is a setting that you will change each tuning to match the lowest plain-wire strings of that piano.)
- Auto note switching: auto all.
- Edit Measure Sequence: set A0, six Cs, and six F#s. (This tapestry gives you the overall shape of the curve)
At the piano:
- Play every note to get a mental preview.
- Look at the string pattern, and make mental note of breaks where you can expect jumps in inharmonicity. Especially note tenor wound strings.
- Start TuneLab, start a new tuning, and see Tunelab set at A0.
- MEASURE INHARMONICITY. Touch the ruler, see "measuring", play A0 loud. Save+ and play A0 soft. Save and repeat with C1, and then F#1, and so on up to F#6.
- MAKE ADDITIONAL MEASUREMENTS: Now be guided by the structure of the piano. Auto-all is very useful here. Measure:
* the highest monochord
* the first bichord
* the top two notes of the bass bridge
* the bottom two notes of the tenor bridge
* the top two wound strings
* the first two plain-wire strings
* at least one note on either side of the treble strut
(What if the piano is 100 cents or more flat? Will these inharmonicity constants change after the pitch raise? Should we raise the pitch first? - The answer to such questions is, don't worry about this until after the pitch correction. At that point, measure one or two of the already-measured strings, and compare to the earlier reading, and decide whether to completely remeasure. The difference is likely to be vanishingly small.)
6. SET THE "MIDDLE INTERVAL" OF THE TUNING CURVE.
- Touch the curve icon to see the curve. Verify Bass interval: 8:2, Middle interval: 3:1 (D3-A4), Treble interval: 3:1.
- Change the Middle interval to start on the lowest of the plain wire strings of this piano. (This 3:1 throughout the plain wire then slowly morphs into 8:2 in the lowest bass, and the changes in inharmonicity are beautifully handled by the additional measurements. After your tuning, play chromatic 10ths through the break and notice how clean the transition is.)
- To change the Middle Interval, touch the wrench icon and select Modify 3-part tuning, and make the appropriate changes.
7. PREP for OVERPULL.
- No matter how close to pitch the piano is, use overpull always, and use it slowly and carefully, because it will give you an amazingly precise first pass.
- Touch Settings and Overpull. Based on this piano, input settings for "bass bridge goes up to", "wound strings go up to", and "treble struts". Make sure the pre-measure is set to C,E,G,C,E,G. Click Start to begin pre-measuring.
- (Pre-measuring needs to be done all at once. There's no way to go back and fix one of the measurements when the doorbell rang. Try to ensure quiet.)
- Play all the notes as requested by the screen, finishing at C8. The display will now go to A0.
8. TUNE FROM A0 to C8.
- Do this very carefully, as these tuning targets are calculated based on very good information. Tune unisons as you go. (It may be helpful to change auto note switching to auto up or auto both, if you notice that TuneLab is jumping octaves from where it should be.)
9. STOP USING OVERPULL.
- When you reach C8, be sure to touch the red stop sign to stop using overpull.
10. FINE TUNE.
- At this point, assess the tuning and proceed accordingly. If it's close, I generally strip mute the center section of the piano and check the temperament octave, then tweaking as I test chromatically all the octaves and double octaves, twelfths, tenths, sixths, fifths, fourths, thirds. When those are right, I pull the strip and retune all the midrange unisons.
- Then I move to the treble, fine tuning as needed. I finish with the bass, using TuneLab down to A1.
11. TUNE THE BOTTOM OCTAVE.
- If there's sostenuto, use it for this, otherwise the sustain pedal will work fine:
- Play, with the left hand A2-E3-A3 and right hand E4-A4-E5, have those notes in the air and tune A1.
- Move down a semitone: play G#2-D#3-G#3-D#4-G#4-D#5 and tune G#1.
- Repeat down to A0.
12. Show off the tuning. Play triple octaves, arpeggios, some Bach or Chopin or Gershwin or the Tiger Rag. Collect the check, pack up your tools, and get the customer's agreement to have it tuned again in the foreseeable future.
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Jason Kanter
Lake Serene, WA
425-830-1561
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