Topic: 'Cents or ratio' option in the temperament display needs improvement

If 'Cents or ratio' is selected as the notation for the value of the tuning of each tone, Pianoteq shows an interval ratio whenever the tuning of a note matches an integer ratio (just) interval closely enough. This would be quite useful if only the implementation were better. As is, PIanoteq typically shows many randomly complex, nonsensical ratios, so that Cents notation has to be chosen instead. For example, in the Pianoteq factory preset, the baroque well temperament Werckmeister III has, in addition to two notes with cent values, 256/243, 32/27, 1024/729, 128/81, and 16/9. So far so good - these are all Pythagorean (3-limit) ratios that the tuning is based on. But then there are these monsters: 783/625, 1044/625, and 2349/1250. These are ratios of 29. The 29th harmonic has nothing whatsoever to do with this tuning, nor are those ratios relevant to the perception of the intervals, at least in this temperament. For instance, the interval that is shown as 1044/625 is 888.2 cents. That's a Major Sixth, a slightly tempered version of 5/3 (884.4 cents).

I propose the following improvement to make the Cents/ratio display useful and musically relevant:

a setting for the prime limit of the ratio that Pianoteq shows (ie. the largest prime allowed as a factor in the ratio).

A similar setting is used in other tuning software, such as Universal tuning Editor (UTE).

Re: 'Cents or ratio' option in the temperament display needs improvement

Wow...no one seems to care about our 'microtonal' demands. I second that, some improvement must be done regarding Pianoteq's 'cents or ratio' view, at least, in order to do some justice to modern western music theorists.

Indeed, for some strange reason, Pianoteq's Werckmeister III scale preset includes 10 rationals, whereas (unless other sources report differently) there should be a total of 8 pythagoreans and no more 'just intonation' ratios on top of those 8, since 4 intervals are supposed to be 1/4comma-flat 'fifths', distributed across the dodecatonic octave-period (4 irrational intervals out of 12, with those 4 requiring logarithmic values, necessarily).

I disagree with the emphatic statements claiming that the 29th harmonic has nothing to do with anything in this case. It has at least something to do in some degree, otherwise no algorithm would have ever found any useful 29-limit approximation close to anything of interest here.

However, you made the point. Assuming the comma 'fraction' be pythagorean's rather than syntonic's (due to the 696.1c 'fifth' being displayed in the same preset), then the resulting 'major sixth' irrational interval should be measuring ≈ 888.27c, rather than being described by 1044/625 (≈ 888.23c).

The latter (Pianoteq's rational approximation, as we see) is quite spot-on in terms of 'difference' (≈ 0.04c), despite making no sense, because 1044/625 misinforms the user right away about the intended historical temperament. As a consequence too, the .1 rounding makes that interval 888.2c instead of 888.3c. Same goes for last step interval (2349/1250), which is displayed as 1092.1c when clicking on 'cents', while certainly it can't be an integer, but an irrational interval to be more fairly rounded at 1092.2c.

Funny enough, that 1044/625 value I was unable to find with tools other than Pianoteq. Checked Yacavone xen-calc, ScaleWorkshop (versions 1 & 2, they use different approximation algorithms) and Untwelve javascript interval calculator. For example, a more 'docile' 29-limit ratio, namely, the semi-convergent 87/52, appears in there, though it exceeds the expected ≈ 888.27c irrational 'major sixth' a little bit (by ≈ 2.73c).

All in all, there is quicker common result, that is, the convergent 11-limit ratio of 147/88 (≈ 888.29c) which is a better approximation (≈ 0.02c 'difference'). As a finer result after that, Untwelve outputs 1034/619, a 619-limit ratio (whose numbers kind catch 1044/625). But that's some heinous, out-of-the-question high prime.

I have no idea where does that 1044/625 (29-limit) come from, but I read that the 29th harmonic is used as a maximum prime-limit in the Scala / ScaleWorkshop v2 'approximate by ratios' function, for computational reasons. Maybe Modartt can tell what's happening on their own front, whether this be related or not?

What else? I think the request of improvement is fine, but, considering also that there might already be better software for scale design and analysis, we need to posit it better, understanding where the best trade-off lies for the sake of both ends (you know, maybe it's not a very easy feature to be implemented as it might look, or maybe it is too time-consuming, down the schedules, etc).

Definitely what has been said about Pianoteq's Werckmeister III preset inaccuracy is worth to note, and leaving as it is is not the best idea. Anyway I would like to add the following: setting largest prime alone without any minimum prime-limit as well (something which ScaleWorkshop v1 allows instead) makes no sense in my opinion. A further improvement of your request, then, would be to allow both min & max prime-limit to be set.

Even more, one could enlist a specific prime-subgroup (for example, 2.3.11), also limiting the results to cut more or less monstrosities eventually arising from exponential ratios. Only in this case the 'temperament view' section would become something more of a scale design nature, rather than a circle graph with more simple ratio display. And monzo notation also might come in handy depending on cases but then again we would get back to square one...too much progress is of no use.

It would be nice if a bit more users were joining discussions like this. Other than that, thanks for your suggestion. Hopefully gets heard. The approximation behavior never bothered me really, but now that I've seen what it does, actually, it does a little bit.

Re: 'Cents or ratio' option in the temperament display needs improvement

martinoduma wrote:

It would be nice if a bit more users were joining discussions like this.

It's always of interest to some - but a bit niche perhaps for most users to wonder too much about I guess. But I would like to see these kinds of discussions so happy to jump in with some support and hopefully a useful thing or two to add...

martinoduma wrote:

A further improvement of your request, then, would be to allow both min & max prime-limit to be set.

Even more, one could enlist a specific prime-subgroup (for example, 2.3.11)

Mostly I support making anything better - so would say nothing new regarding the requests/ideas expressed here.. I think there's very good food for thought, and wish to add my thanks to you both.


Happily I'd join in more too however my use-cases regarding temperament are often outside of concerns about getting things to align to historical figures (personally I don't mind ugly fractions - had not considered the interface might limit certain things I didn't experience a personal desire for - but was not all that aware that these might not stand well within some other use-cases). So definitely - if possible it would be something I'd like to support being extended/improved.

Absolutely I love creating my own variants of period temperaments and newly create micro-tunings for specific pieces - but mostly I work on completing this by ear (and may take months.. allowing things to sit.. then return a number of times before deciding on exact things, per piece, which is possibly outside of the realm of informed discussions about temperaments btw), rather than via mathematical devices. I still wish to know at least enough about the topic that it stays interesting (it is indeed fascinating how so many temperaments were the result of seeking a mathematical theory, or some kind of perfect truth etc. and also fascinating, at least to me, that I can love some, dislike other temperaments - and for such different reasons, for different music etc.. and even for sure, for different pianos esp. the historical collection).

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