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I believe what Roy describes as "unison settling" has more to do with Newton's third law. The effect I mentioned earlier is different. It proceeds from the premise that the unison is tuned clean and stable. Yet, when each string in the unison is plucked, there is an aurally detectable difference in pitch, albeit ever so slight. A basis for the theory as to the cause was mentioned earlier.

After reading the Doctor's explanation of his theory, I am a bit confused. What Mark is saying seems slightly different, but makes better sense. Look forward to further info on it.

Bob, I believe also that the tuning pin can be introduced in the tonal result. as soon as the tip leaves the tuning pin, that one is free to vibrate. it could be changing the structure of the sound.

(it is in fact)

Thanks, Isaac. Interconnectivity opens up a plethora of possibilities. Will think on that one...

Thanks, Isaac. I must have missed your edits. If I understand you correctly, I think you and I are describing the same effect.

Certainly Bob, , in the end it is also seen on an ETD display , as a tew 10ths or cts, and more than that sometimes,

I suggest that the first reason why it is so much unsuspected, is that generally the piano tuners never pluck the strings in they unison.
Also, plucking a string with the 2 others open may give a very differnt pitch that if a felt mute is used to mute them.
SO probably we are fully in the effect Mr Weinreich tried to describe.
I also believe that due to instability of the pitch of piano strings, it may have been difficult at the time of the tests, to have the help from a tuner that knows the effect and how he uses it.
More often it is noticed but considered not important, un unison being 2-3 strings.
Rarely tuners make the analysis of which string is used as a "ballast" (?) to color the strong coupling 2 others. it may be the central one, or any other even if instructions may exists as stated in the above post from 2006, to tune an "open" unison between the first 2 strings, and another open one for the 2 last (a common way to have a nice sparkle I find here)

THe hypothesis is simply that the strings have a natural attirance to that unbalance, and that they will land there anyway after the piano plays a little.
SO better master the process from the start.
ALso noticed is the shape the most naturally obtained when using a stripmute, where the first central string gives the pitch and the 2 others maintain it (by being tuned high) , while providing a strong trunk for the unison (I even see that 2 external coupled string as a "barrier" that will avoid the drift of the central string too much.
Those sort of things are difficult to test and to proove, but whenever you find old tunings with clean unisons check the "shape" it will be that one ("smiley" shape, as say Alfredo)

It happens that, beginning with such a shape I finally wish to have more power for the attack, I then "close" one of the external strings. The perfect 3 strings is unstable, I do not know a real reason (probably because they are all exited in the same orientation, while they cannot physically vibrate all the 3 in the same up-down process - there is an obligation of "phase opposition" but that may relate to the Newton law as well

Best regards

Hi Chris,

Your steps are interesting from a theoretical point of view. However, as a practical consideration, one can go straight to step 2, without the need to prove or disprove this particular theory.

You see, if there is a pitch change, Double String Open Unison (DSOU) tuning will minimize it and preserve a high precision interval, like a pure triple octave for example. (I prefer giving a different name to this technique than just "shimming", which can also identify the process of correcting a unison, and not actually tuning from the beginning with this technique.)

If there is no change, the DSOU technique does no harm, and there are still other benefits, like no need for a strip mute, no string stretching due to strip mute insertion and removal, ease of tuning for birdcage, beat matching for speed, etc, to be had.

I find many tuners tune at very high levels without the need to understand why things are happening; they go straight to your step 2. Their technique can be so natural after years of practice, that the analytical process is happening at a subconscious level. (Read "Blink" by Malcolm Gladwell.)

My interest in understanding these concepts is so I can teach other people how to tune naturally in a shorter time; I believe an analytical understanding of a process can facilitate natural knowledge faster than just practicing, providing it is not done too much. (Paralysis by analysis) I have had to "let go", at times, of the need for understanding in the past in order to get results sooner. Not easy for an engineer. But in the long run, it helped; the understanding came later. (That would be your step 2, then 1.)

I am curious. Are you a piano technician? If so, do you find you are more analytical or natural in your approach?

Lets keep in mind that when we pluck a string at a point different from exactly the point where the hammer strikes the string, a different harmonic balance will be created. That pesky seventh partial can be very tricky.

Plucking creates a different harmonic balance from hitting with a hammer.

yes that play a role on the spectra, but the height difference stay audible. pluck the string at different location, the fundamental perceived stay the same.

plucking particularly in high treble, make us hear directly the iH, when compared with the hammer hit pitch.
But when all 3 strings are plucked, it is enough to pluck on the same line more or less.

some ear training is necessary to listen to the tone in an analytic way, that mean not simply chasing for beats.
In the end that is the prompt sound which is shortened or lenghtened . the crash tone of the hammer is coloured when stabilisation is fast enough.

The easiest part to understand, said the beginner tuners, then the hard part is to be able work the string at the wanted level of precision and have it stay in place, and it can take around 2 years with adequate environment and teatching.

Yes.

Mark, I can't be sure, but I think this is yet another example of a thread discussion that's gotten derailed.

Best of Luck,
Chris S.

If you are a professional, the rules of the board are that you should state your affiliation in a signature to your messages. See the notice to professionals in the Piano area.

Oops,

My bad. Should be all fixed now.

Thank you Mark. This method was a lifesaver for me tuning an older English piano called a Eavestaff mini-piano. This very short piano has the action and strings mounted in the back of the piano, but the double-ended tuning pins go though the pinblock and protrude at the front of the piano below the keybed where they are tuned. It is impossible to manipulate mutes and tune at the same time without physically moving around the piano for every change. Because this piano has only two string for every note from middle C to the top F, the Double Unison Technique worked wonders for the second pass of a pitch raise without having to get up from the sitting on the floor position! (The first pass I just listened through the beating unisons to the target string.)

Cool. Had you heard about this technique before, or did you just try it out based on my explanation of how to use it?

Mark, I tuned this piano only the week before your post. I had thought of something similar some years ago as a method to set temperament intervals but never pursued it until the necessity of this piano. Your post was coincidental and most timely in that it legitimatise what I did, in a sense, because how I tuned the treble octaves was identical to your description. (This little piano has single strings below middle C so the temperament is set there.)

Hi Roy,

Yes, I was.

Although after contacting Professor Weinrich he set me straight. After tuning a single string to a specific pitch, and then adding the two other strings to produce a clean and pure unison, there is a phenomenon that occurs, described by Professor Weinrich, which states:

The final pitch of the three stringed unison will:
1) remain the same,
2) go up, or
3) go down.

There is no way to know which it will be.

At first I thought like most people, that it would go down, but then when I tried to demonstrate this to others, sometimes it would go down, but other times it would not change, or would go up, putting a wrench into my hypothesis, and leave others thinking I was a crackpot, and me; scratching my head.

Contacting Professor Weinrich helped me to understand why my demonstrations were failing.

No matter why you think this is happening, many advanced tuners recognize that something is going on here. Some try to predict the drop, and tune their first string slightly sharp. But if the effect results in a rise, the final unison will be even more out.

The only way to eliminate (or reduce) this effect, is to tune two strings first, find the desired pitch of the double string unison, and then bring in the third. The final pitch doesn't change because the double string has already been affected by the Weinrich effect. I find the pitch much more consistent, and the quality of my treble much better than it used to be.

If you are working on producing consistent triple octaves, or consistent pure 12ths in the treble, or any other consistent SBI in the treble, you have to tune with double string unisons. There's no other way, except going over the notes multiple times. The double string unison technique gets the note there precisely, and it stays there, if stability is good of course. It is much faster than constantly tweaking the notes that have drifted. I just did a concert tuning with consistent triple octaves, in 60 minutes.

If you have not reached this level of precision yet, it is not worth the effort.

Please post any questions if you have them.

I spend most of my free time producing free video lessons for beginners. If there is a demand for this level of video lesson, I will make one. Let me know.

you also can have your couple between leftand right string, or something balanced between 2 couples opposed around the center string.

More experiments would be interesting on the predictability of the final pitch, but one may take in account that the pitch of "open unison" (tone wise) stabilize after it have been heard and noticed by the brain, in my opinion.

Mr Weinreich did not have at hand a tuner that could use different "shapes" of unison. Many do not do that consciously, while some use one approach only. One of the most respected tuners here told me "sometime there, sometime elsewhere, no rule" Each string is treated individually and in its relation to others, knowing from the start we cannot force them to stay going all 3 together in the same direction, as this is not natural , as an effect.

When using and ETD and trying to quiet the display it is easy to overpass the good spot just for a better display. while it may be useful with only 2 strings, when a 3d is added the display get really useless in my opinion.

Uh, ... yea. Some pianos require a little tweaking of the unisons and some octaves, ... some don't. There is a great danger of over-thinking this. For me, the KISS principle applies.

Thanks for the comment David. Are you saying professor Weinrich is over thinking this phenomenon?

This tweaking thing really gets to me. If I spend a lot of time setting pitch and stability and then it drifts, this causes a great deal of frustration for me. With double string unisons, I have greatly alleviated this stress. I feel more like a professional now that the pitch stays where I put it.

As an aside, I put together a list of reasons for open unison tuning and a list of reasons for double string tuning. Open unison had three reasons; better stability, faster because no mute strip needed, and forcing the tuner to tune clean unisons because they will be used to tune other SBI's like 12ths and 22nds.

Double string tuning had 11 reasons. I won't list them because they refer to other techniques I use with the DS method that won't make sense if I post them here.

It just made me understand a bit why more tuners don't use open unisons. But with DS, I think it would be harder to dismiss if people really knew and understood all 11 reasons.

When tuning without mutes you are obliged to interfere with the power output. this can be helpful and you are possibly helped not to "close the tone" too much.