Tuning styles in depth explanation please!

Abraham Lee

I'm coming from regularly using Verituner and I've really liked the built-in 3 tuning/stretch styles it has for you to choose depending on the scale of the piano, "Clean", "Average", and "Expanded", for smaller, typical, and large pianos, respectively. Obviously, the tuning style algorithm in pianoscope is going to be (likely) different from how Verituner does it, but I would love to understand pianoscope's way of doing it better in order to get similar results, and maybe I already can, but just don't realize it. I have no intention of arguing the merits of any particular tuning style, but just want better understanding. I can't imagine I'm the only one.

So, in Verituner, its tuning styles are basically a point cloud of pitch/interval/beats/weight values. For example, the "Average" style is defined like this:

A0 6:3 0.33 100%
A2 6:3 0.24 100%
A3-4 4:2 0.32 100%
F5 2:1 0.30 100%
A6 4:1 0.50 100%
C8 4:1 0.00 100%

I've been studying the documentation (link to the section here) to try to understand pianoscope's inputs and method better, but I just don't get it well enough how the inputs play together to create a comparable tuning style like Verituner. For example, why can't I make an interval weight 0%? Does the minimum value of 1% basically do the same? Do I have to go through ALL the intervals and "zero-out" all the ones I don't want it to intentionally consider? What about the "Maximum Pitch"? Why is that fixed and not user changeable?

Anyone have some insight? While the documentation is well-written (well done, Frank), I still don't understand how to really make it bend to my will like I can do so easily in Verituner. Very grateful for any advice on the matter.

Frank Illenberger

Abraham Lee The main idea of the tuning curves in pianoscope is that there are no rigid regions in which tuning intervals are matched. Pianoscope looks at how strong the partials of a tuning interval are in a certain note range and weights them accordingly. (If you look at the deviation curves, you will see that the color saturation of the line for a tuning intervals denotes its strength). These intrinsic weights are multiplied with the weights set in the tuning style. The main benefit of this is that you get smooth transitions between matching zones which results in very nice tuning curves.
Another aspect is that with pianoscope, you as a technician don't need to decide which tuning intervals to pick for an individual instrument. With Verituner, depending on the instrument size you will need to pick different tuning styles. This is not the case with pianoscope. Its algorithm for example automatically reduces the weight on higher order intervals (like 10:5, 9:3) for smaller instruments. So out of the box, the default tuning styles are very adaptive and you rarely need to manually adjust individual weights. If you choose to do so, the best way to get a feeling for what they are achieving is to go to the deviation curves, switch them to show beat rates, activate the intervals you are interested in (by swiping you can show multiple intervals at the same time, like twelfths and octaves) play with the weights and immediately see which intervals will result in which beat rates.

Abraham Lee

@Frank Illenberger any thoughts? The more I look at what pianoscope is accounting for, the more I feel like there are too many variables/weights to feel like I know I'm getting what I want.

Any chance you could explain the "maximum pitch", how it's chosen or set?

[deleted]

Frank Illenberger Frank, I 'converted' someone from 'Balanced' to '12ths' and he had been using 'Balanced' the whole time. His conclusion on both grands and uprights was that the pianos consistently sound cleaner and more beat-less with '12ths' and I think you may want to reconsider this in your next updates.

Abraham Lee

Frank Illenberger very interesting. Thank you for explaining further. That helps somewhat, but I think I have to study it and the app more.

May I ask, how did you come up with the weights for each of the built-in tuning styles?

Frank Illenberger

Abraham Lee The weights are calculated in such a way that they result in the beat rates desired by the respective tuning style. Pianoscope's approach differs from that of an aural tuner, as it not only optimizes for a few selected tuning intervals, but performs millions of tests that could not be done by hand.
If you want to play with this weights, it is good to start from an existing tuning style and if you are not content with the beat rates of a given tuning interval in the deviation curves, you can raise or lower the respective weight.

Abraham Lee

Thanks for more explanation, Frank. Still in the process of analyzing each of the built-in styles and the respective interval weights. I'm really enjoying being able to try out tunings, then listen to intervals and their partials to see what the effect would be and see their beat rates. Very cool!

One thing I'd like to recommend, if I could, is some kind of "revert style to last used" button, so that I can play around with things and then undo them without messing up what I might have chosen to actually tune with last time. Does that make sense? Or, maybe an "Apply Tuning" button somewhere so that I don't accidentally change it, when I don't want to save it, just play around? I'm not sure which option would be better.

One final question(s), if I may. I've already brought up the "Maximum Pitch" before, as it applies to the note range with which an interval weight is applicable. That's great. I'm wondering if you could shed some light on how that note is/was chosen? Is it calculated with each piano? Is it hard-coded (for example, is the 3:1 twelfth interval max always G#4), since I noticed that all the built-in styles show identical max pitches for the respective interval? And it looks like the highest pitch of all the intervals is only C5, with the 2:1 octave. What kind of interval does pianoscope shoot for above this pitch?

Sorry, I know I said final question above, ha ha, but I have one more. In the tuning curve menu, there's an options to use "absolute weights", but it doesn't seem to do anything, or at least not that I have noticed. What's going on with that?

Thanks so much!

Frank Illenberger

Abraham Lee

There already is a revert function like the one you suggested. To revert the edits you have made to a style, go back to the styles list and swipe left on the name of the selected style. A red button titled Discard Changes will appear. https://www.pianoscope.app/manual/en/pianoscope.html#_saving_and_discarding_changes

There is no maximum pitch for a tuning interval in pianoscope. The weight of the tuning intervals slowly tapers off, as indicated by the color saturation of the deviation curves. It goes asymptotically to zero but never actually reaches zero. The absolute weight value of a tuning interval does not play a role, only its relation to the weights of other intervals. So even though the weight of 2:1 is low in the high treble, the weights of the higher partial intervals are far lower.

The absolute / relative weight switch is for the same purpose. If you want to compare weights between intervals, make sure to set it to relative. If you want the highest possible color contrast inside each interval curve, choose absolute.

https://www.pianoscope.app/manual/en/pianoscope.html#_relative_absolute_weights

Abraham Lee

Frank Illenberger Per the "Discard Changes" button, sometimes I don't recall which built-in style I chose last when I'm toggling through the options. Maybe all that's needed is some indicator like an asterisk or text below the name that says "Last Used" would help to know which one I chose. That, or have a button that will revert all changes/choices to whatever was chosen last time I hit "Done" in the tuning curve area. I think that would be very helpful for folks like me who are playing with the tuning styles and go too far down the rabbit hole lol.

Abraham Lee

Ok, that's making more sense. Thank you for the clarification of the interface and controls. I'll keep playing with sliders to understand what they're doing better.

Abraham Lee

@Frank Illenberger , I think I'm really starting to understand the Tuning Styles area. So, thanks for all your help!

As I'm playing around with this, I think it would be really, REALLY helpful if the Max Pitch value were editable as I do feel a bit constrained by this.

So, with the weighting, would you say that this is more like a bell-curve weighting for each interval that builds gradually to the Max value and then decays gradually? I feel that some more explanation about how your algorithm is constructed would really make this part of your software much more valuable than just saying "Oh, just trust me and use one of the built-in tuning styles because they're great!" Maybe just me. I really want to understand so I know how to adjust it when I don't feel like I'm getting the results I want. Because right now, I feel like I'm shooting in the dark, randomly selecting one style over another without understanding why.

And with the "intrinsic weights" you mentioned, are those weights based on the actual audible intensities of each partial?

Frank Illenberger

Abraham Lee

As I'm playing around with this, I think it would be really, REALLY helpful if the Max Pitch value were editable as I do feel a bit constrained by this.

I had this request before. I might add this feature in a future version.

So, with the weighting, would you say that this is more like a bell-curve weighting for each interval that builds gradually to the Max value and then decays gradually? I feel that some more explanation about how your algorithm is constructed would really make this part of your software much more valuable than just saying "Oh, just trust me and use one of the built-in tuning styles because they're great!" Maybe just me. I really want to understand so I know how to adjust it when I don't feel like I'm getting the results I want. Because right now, I feel like I'm shooting in the dark, randomly selecting one style over another without understanding why.

The intrinsic weights are built from an average from measurements of typical pianos and are not based on an individual instrument's measurements. Their shape is not exactly bell-curved but similar. I don't want to disclose specific algorithmic details as I consider this a secret sauce.

Abraham Lee

Frank Illenberger Oh! I though the intrinsic weights were based on the piano I'm working on in front of me. Good to know. Why aren't they based on the current piano like the inharmonicity measurements?

Frank Illenberger

Abraham Lee The colours you are seeing are the actual intensities from the piano in front of you. But for weighting in the tuning, pianoscope uses averages from typical pianos. In version 1, pianoscope also used the actual intensities for the tuning curve calculation, but it turned out to produce inferior curves which were also too dependent on microphone characteristics.

Abraham Lee

Frank Illenberger So, in the interval plots, the color intensity IS from the piano I'm tuning, but the weights I can adjust for the various intervals to customize the tuning have an underlying intrinsic weight based on an average of typical pianos that modifies it for the algorithm. Is this to help counter the effects of the (likely) device's inferior microphone capabilities?