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Intonation Problems - Equal Temperament

Posted: 21:28, 16 August 2017
by tommy1212
Having just purchased a new Roland FA-08 at retail, with high expectations for enjoying its capabilities and quality, I was surprised and disappointed to find what I consider to be a significant defect in the instrument's equal temperament intonation. This issue could affect the entire acoustic piano category, and perhaps extend to other tone categories as well.

In playing a major scale from C6 to C7, using the Full Grand 1 tone, I perceived (initially by ear) pitches which were inconsistent with a normal equal tempered scale.

To verify whether this discovery was accurate, I tested two other identical FA-08 instruments, which were floor demonstration models at the same retailer. Both exhibited the identical intonation symptoms as my new instrument.

In testing one of the two demo FA-08s, a chromatic digital turner smartphone app was used, which displayed the anticipated pitch deviations. Thereafter, I tested my instrument using a Korg ToneWorks rack mounted chromatic tuner.

The Korg tuner not only verified the C6 to C7 hypothesis, but pitch inconsistencies were also found elsewhere on the keyboard.

In equal temperament, when an instrument is calibrated to A4 = 440 Hz (i.e., the A above middle C), the pitch of the perfect octave above it, A5, should be 880 Hz. The Hertz frequencies associated with each equal tempered pitch is precise, when the instrument is properly tuned.

So far, I have found no Internet references to intonation problems associated with the FA-08. Roland's U. S. support representative says no such incidents have been reported since the product's release in 2014.

My instrument is using 2.0 firmware. A factory reset has been initiated several times to reduce the possibility that the problem is a firmware related anomaly.

I'd be grateful to hear any possible remedies or constructive suggestions on how to address what is for me a troubling issue.

Thank you.

Re: Intonation Problems - Equal Temperament

Posted: 21:33, 16 August 2017
by bennyseven
Is it Full Grand 1 only?

Re: Intonation Problems - Equal Temperament

Posted: 23:01, 16 August 2017
by tommy1212
Unfortunately, I don't think so. The intonation issue appears to propagate at least to the other initial acoustic piano preset tones as well, and perhaps deeper. I have focused on Full Grand 1 as a starting point to be certain, before raising the issue to Roland and the FA-08 user community. The other initial ac.piano presets (from 0002 Full Grand 2 to 0008 Rock Grand) seems to be confirm the same behavior, but with variables owing probably to the overtone characteristics of the particular sample.

Testing primarily the C6 to C7 major scale, the general pattern (according to the Korg tuner display) is a 5 to 20 cent sharpening of most scale degrees. The Korg readout is in increments of 5 cents each. A digital multimeter with a Hertz setting would probably provide a preferable numeric measurement.

Thanks for your interest.

Re: Intonation Problems - Equal Temperament

Posted: 00:58, 17 August 2017
by Paul99
I don't have a tuner so I cannot check, but here is something strange I found out:take 0001 Full Gand 1 and hit the F6 key and let it loose immediately. Now do the same with G6. Hear something different? Without the use of the sustain pedal, F6 disappears when you let loose of the key. But G6 keeps somehow sounding when you loose the key as if you kept the sustain pedal pushed. All the upwards notes above G6 do the same. I turned off the reverb, but that would not be the cause because the reverb sounds the same over all notes and not only above F6.
I checked other pianos: from 00001 Full Grand until 0099 Deep Grand all have the same problem. From 0001 128voicePno onward it is correct working.

Could this be something that came with the v2?

Re: Intonation Problems - Equal Temperament

Posted: 02:23, 17 August 2017
by tommy1212
Yes Paul99, you're right. Thanks for testing that register of the keyboard for defects. At least with those presets, you presently can't play staccato on G6 (and to a somewhat lesser extent A6 also). Even after the depressed key is released, the sample continues to resonate when it should be instantaneously dampened.

Having spent so much time in this range of the keyboard, I too had identified the G6/A6 flaw, but didn't mention it to keep the focus on the intonation issue, which to me is bedrock for any fixed pitch instrument.

I upgraded to 2.0 firmware just after purchasing the FA-08. So, I can't tell whether the G6/A6 unwanted ringing issue was present in the prior firmware version, or indeed whether 2.0 actually created it.

These are basic production quality control issues which have somehow been bypassed or ignored, very likely because users are either not noticing, or at least aren't complaining. If sales continue unabated, there is no incentive for Roland to fix these demonstrable problems.

Re: Intonation Problems - Equal Temperament

Posted: 04:39, 17 August 2017
by stevel
It is possible that the piano is tuned in "Stretch Tuning".

On real pianos, they are not perfectly in tune either.

What a great piano tuner does is not tune the octave above a string to the octave below - thus A 880 is not tuned to A 440.

Instead, a piano tuner tunes the upper A to the OVERTONE of A 440.

Mathematically speaking, the overtone of A 400 should be A 880.

However, in real life, the thickness of the string produces an area where there is no vibration that is essentially subtracted from the string's length. Shorter string = higher pitch.

So the 880 is more like 880.03 on the real piano.

Every single piano is different, and every single overtone is different, and since many pianos use different string sizes, the numbers are all over the place.

The piano tuner at our university uses a device that "listens to" the overtone content of each string (and it actually can store every piano at every place he tunes so he can recall them each time he tunes!).

You can easily see they're not perfectly in tune with the fundamental.

Ordinarily we use the general term "Harmonic" for an overtone but really that word should only be used when the numbers are pure - that's what "Harmonic Overtones" are - 110 - 220 - 440 - 880 - 1760 - etc.

But most musical instruments have a natural amount of "inharmonicity" to them - in the case of the piano it's due to mass/diameter of the string and the nodes and anti-nodes. What this means is each overtone gets slightly sharp.

So if they tune A below middle C, they tune the octave A to the OVERTONE of that note, which is a little sharp, so that A is a little sharp - this makes the octave a little bit bigger, or "stretched".

Now, they don't start at the bottom of the piano and keep working up, because ultimately it would be way too sharp at the top.

So what they do is, they tune the center octave (the range most people play in) and stretch outward from the middle to the ends - so the lower notes are a bit flat and the higher notes are a bit high.

This practice makes a piano sound "in tune with itself" and is an important skill and craft in piano tuning.

A piano in perfect 12tet won't sound quite right and will be a bit sterile compared to the real thing - a problem synthesized/sampled keyboards have had to learn to deal with.

Your result of it being sharp in the C6 to C7 octave follows stretch tuning principles pretty well.

Try a lower octave and see if they're low (not sure if you're using C4 as middle C or C3).

This video explains Stretch Tuning pretty well:

https://www.youtube.com/watch?v=ufTTArPLlZo

Re: Intonation Problems - Equal Temperament

Posted: 12:58, 17 August 2017
by Skijumptoes
Yeah piano tuning truly is an art, i tried it myself using some software and the right tools, and it's ridiculously complicated, and as you say, some compromises have to be made. In fact, it's only when you start tuning a piano that you sometimes question whether it should be classed as a string instrument, cause you spend so much damn time looking at the strings resonating! :)

Whether Roland have put 'realistic' tuning errors/compromises into the supernatural engine, who knows?! I rarely spend much time in the C6-C7 range so it's not something i would notice if it was out of tune. But i've had no tuning issues.

Very interesting to read your findings though, tommy. May have to try it out myself later and see what i get.

Re: Intonation Problems - Equal Temperament

Posted: 00:04, 18 August 2017
by piaknowguy
Tommy,

I would like to hear an example of how this issue affects your music. Could you post a recording?

Re: Intonation Problems - Equal Temperament

Posted: 03:05, 18 August 2017
by gg22
Regarding F6/G6 - that's completely normal, that's how a real piano behaves.


https://music.stackexchange.com/questio ... ower-notes

Which makes me think the "issue" with temperament is not an issue as well.