On Jul 1, 2021, at 0:56, philfrei via <philfrei@...> wrote:

I've been reading about the "Railsback curve". Is there a way to implement this on a DX7?

For those not familiar, this refers to deviations to the mathematically pure 2:1 ratio for octaves that are often implemented by piano tuners. I'm curious about this, in part because of intonation issues when playing my oboe along with recorded DX7 parts. The higher notes of the DX7 sound progressively flatter compared to what I'm naturally playing on my acoustic instrument. I've been working to adjust my acoustic instrument's pitch to accommodate, but from what I've recently been reading about "subjective octaves" (that for orchestral instruments, they may in fact have a stretch-octave curve similar to the piano's Railsback curve), I'd like to experiment with having the DX7 accommodate my acoustic instrument, instead.

Reference links:

On Jul 2, 2021, at 0:34, philfrei via <philfrei@...> wrote:

Thanks. I found the Microtuning section in my DX7S manual. This is interesting, and looks like it could accomplish the task, albeit one would have to calculate and enter values for each note. My only hesitation is that perhaps the "fine" tuning could benefit from being slightly finer for a smoother fit to the Railsback curve.

When I bring up A3, my display reads as follows:

>Micro tune< A3

f: A3 + 0?? 5802

We are in "fine tuning" mode, designated by the "f". Clicking the data entry +1/ON button changes the second line to the following:

f: A3 + 1 ? 5803

If, from the same starting point, but in "coarse tuning" mode, designated by "c", the same action (incrementing the value by one) results in the following second line displays:

c: A#3 + 0 ? 5888
c: B3 + 0?? 5973
c: C4 + 0?? 6058

I am curious about the right-most number. The coarse appears to vary the right-most integer by 85 (but sometimes 86), and the fine appears to transition over the intervening increments. I can see that this matches the 1.17 cents approximation that you referred to. I'm guessing the large integer is the index column of a data table that encodes frequency.

I've not found a source equation or chart yet for the Railsback values. I've read estimates of 10 to 20 cents perceived stretching occurs even for the middle octaves, even thought the Railsback adjustment made there is smaller. I suspect that the adjustments made by piano tuners, which are less in the middle registers and more in the outer registers, reflects a compromise that derives from common use of those frequency ranges. Around middle C, we are more likely to use "close-voiced" chords, and in that context, beating between the notes might be more annoying, whereas at the extremes, where open-voicings are used (octaves, or at the least fifth), the "stretch" could be the more discomfiting factor.

On Jul 3, 2021, at 0:54, philfrei via <philfrei@...> wrote:

I did a search for the CP 80 manual, and am only finding it behind paywalls (average cost around $16) or from sites that are attempting to give me trojans. Yamaha's only CP series manual, if I did the search correctly at their site is for CP 88 (or a supplement with additional voices that came out later). Searches on the words "pitch" "intonation" "tuning" didn't show what I was hoping to find.

If the chart is a true Railsback implementation, I'd seriously consider purchasing it. But I can't tell from the info you gave if that is indeed what it is. You mention a pitch range (-23 to +35 cents). This suggests to me that the setting is used for coding temperaments. For the "Railsback curve" stretch, each octave, working outward from Middle C, would have more deviation than the previous, and so, the desired amount of deviation would lie outside the range.

The nice thing about the DX7 series performance intonation settings is that as the stretch accumulates, it is possible to make use of the "coarse" control, if needed.

On Jul 3, 2021, at 3:27, Nicole Massey <nyyki@...> wrote:

Anyone know if there are microtunings out there on the web for standard things like stretch tunings and the different mean tone options?

Sent from my HAL 9000 in transit to Jupiter


-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of philfrei via groups.io
Sent: Friday, July 02, 2021 10:54 AM
To: [email protected]; danforcz@...
Subject: Re: [YamahaDX] Intonation on DX7

I did a search for the CP 80 manual, and am only finding it behind paywalls (average cost around $16) or from sites that are attempting to give me trojans. Yamaha's only CP series manual, if I did the search correctly at their site is for CP 88 (or a supplement with additional voices that came out later). Searches on the words "pitch" "intonation" "tuning" didn't show what I was hoping to find.

If the chart is a true Railsback implementation, I'd seriously consider purchasing it. But I can't tell from the info you gave if that is indeed what it is. You mention a pitch range (-23 to +35 cents). This suggests to me that the setting is used for coding temperaments. For the "Railsback curve" stretch, each octave, working outward from Middle C, would have more deviation than the previous, and so, the desired amount of deviation would lie outside the range.

The nice thing about the DX7 series performance intonation settings is that as the stretch accumulates, it is possible to make use of the "coarse" control, if needed.

On Jul 4, 2021, at 2:26, Eb Myatt via <eb.myatt@...> wrote:

On Jun 30, 2021, at 11:56 AM, philfrei via <philfrei@...> wrote:

I've been reading about the "Railsback curve". Is there a way to implement this on a DX7?

For those not familiar, this refers to deviations to the mathematically pure 2:1 ratio for octaves that are often implemented by piano tuners. I'm curious about this, in part because of intonation issues when playing my oboe along with recorded DX7 parts. The higher notes of the DX7 sound progressively flatter compared to what I'm naturally playing on my acoustic instrument. I've been working to adjust my acoustic instrument's pitch to accommodate, but from what I've recently been reading about "subjective octaves" (that for orchestral instruments, they may in fact have a stretch-octave curve similar to the piano's Railsback curve), I'd like to experiment with having the DX7 accommodate my acoustic instrument, instead.

On Jul 2, 2021, at 4:51 PM, LarryS <vision1@...> wrote:

I have a chart in a piano tuning book that shows stretch tuning.

Well, maybe I do. ?It's buried somewhere.

L.

Hello?All,

FWIW, I just found some tables that I did decades ago regarding alternate tunings on the DX11.

One limitation of this is that these tunings apply?uniformly in all octaves i.e. they are not?“fractional” tunings.?

I suppose that you could layer different octaves to make a?“polyphonic” voice … not sure if this approach would work on the DX7s though. Please find attached two such examples.

Greetings,

E?

<Equal.rtf><Werckmeister.rtf>

On Aug 20, 2021, at 3:51, philfrei via <philfrei@...> wrote:

Hi - I just spent some time reviewing the replies on this thread. I was a bit scared of the link Danial Forro posted in July 2, as it "felt" like with all the ads and links and such it could be a source of malware. I may have hit a malware warning on my first try, I can't recall now.

But the download from this link did download a PDF with Railsback numbers.
Here is a screen shot of the table.

<RailsbackYamaha.png>

<RailsbackYamaha.png>

On Aug 20, 2021, at 3:26, philfrei via <philfrei@...> wrote:

Thanks for the nudge. I was personally emailed a file with settings that contain pitch adjustments for every note, and the equation that generated the numbers. It looks quite interesting, and was developed by the person who contacted me. I assume that the individual reads this list and I'd like to encourage them to share the chart and equation with the full group.

The bottom line, though, is that I don't know yet if there exists a chart on the Railsback effect produced by Yamaha engineers in any of their manuals. I've been a bit more focused on learning whether or not there is an industry-level standard practice on the issue than in testing how it sounds. So far, from the various people who are closer to studio recording tech than I, there doesn't seem to be much use or awareness of these pitch adjustments, which kind of surprises me. Maybe it is related to the ability of an acoustic musician to make adjustments on the fly, as I learned to do when playing the oboe in the studio.

So, unfortunately, the task of testing how it actually sounds got back-burnered. A related project, more front and center a the moment, is a pilot test I have going for an experiment on whether timbre affects the perceived pitch of notes. I'm collecting data from a handful of people, and need to find a good data-analysis person to ensure that what I'm collecting via the test is suitable for quantifying/modeling. (I'm more a composer/programmer than a scientist.)

I haven't used my DX7S in the studio much lately and figuring out the logistics of inputting and using the data is a bit nervous-making (due to unfamiliarity), though probably doable. I've been doing more with an FM synth I programmed using Java that can produce equivalent voices to those I developed on the DX7. When I get a chance, the plan is to work the Railsback Curve data into the functions that convert MIDI pitches to Hz and vice versa, and see how it sounds. If I get this working, I'll post links to a something that compares the two intonations back-to-back. But it could be another month or more.

>From: Eb Myatt
>Date: Thu, 19 Aug 2021 02:19:50 PDT

>Good Morning Phil,
>
>We haven't received any feedback from you since you last posted. So, did you manage to resolve the >"Railsback" tuning issue that you discussed? Please let us know if you have the table for the DX7s >or any other Yamaha synth ?
>
>Best Regards,
>E?

Am 20.08.2021 um 09:56 schrieb Daniel Forró via <danforcz@...>:

I have found in my archive another table sent to me by George Chakiris, it uses only small differences. I attached it.

The basic question is how stretch tuning will sound with FM generated electronic piano sound, which is far from the real acoustic piano sound, and if it has any reason to use is. I don’t think it can help to improve sound.

There was interesting discussion many years ago in microtonal composers circles about the relation between timbre and microtonal tunings. I think the person behind the research is a microtonal music composer William Sethares. Try to start here:

Daniel Forro

<DX7II stretch tuning.jpeg>