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This is an interesting paper:
http://www.dei.unipd.it/~avanzini/downloads/paper/avanzini_jasa12_authorcopy.pdf.
It explains and quantifies the pitch glide effect (frequency decay) due to tension reduction during string relaxation. This is a very complex nonlinear effect which contributes to the piano tone. But it also affect tuning. Pitch and partial composition is different at each instant of time and depends on key velocity. Aural tuning takes into account this behaviour by searching the best compromise. I have tried by Ultra Tune and while tuning was good after a few seconds decay initial tuning was bad. So, what is the best compromise when using automatic tuners ? And partials composition is an averaged value over the decay time, the initial or the final value ?
Thanks
Regards
Angelo

Angelo:

For aural tuning I would think that any such "frequency decay" would be hard to detect (largely self correcting) because all notes would be decaying. "Searching [for] the best compromise" does come into play when aural tuning, but for other reasons.

Thank you for the paper.

That is the main point, I always say that tuning with ETD make the tuner tune later, hence a different pitch appreciation than when tuning aurally.

The answer is that one need to know aural tuning to efficiently use an ETD.

The tone is probably "sustained" when tuning unison by "pushing the envelope" (coupling in higher partial range) that fight the pitch lowering of one string only. Difficult to be sure, as there are other effects , added mass by coupling at bridge location more or less fast energy absorption.

I never find a study conducted with concert tuners tuning the instruments all the samples provided in the studies I have seen where at best mediocre. (certainly the major brands have such data)

It remains to be seen if the effect on pitch (known for well over a century) is anywhere near what is audible and/or measurable in a piano.

The increased tension during a test blow which tends to drop the pitch of a non stable note seems an indirect consequence of this nonlinear string effect.

Kees

The fact that tuners have been doing great work for as long as there have been pianos without getting in knots over the phenomenon is testimony that the effect is negligible.

As far as I know tuners strike the string very hard to equalize the tension along the string itself. But tuning should be performed after the fast frequency decay. And this is what happens usually with electronic tuners since you need time to adapt the string tension on the basis of the visual feedback. And also aural tuners require time to count beats. This means that perfect tuning cannot be obtained immediatly after strike and also unisons are not perfect initially since tension is not the same in the three strings. But this contributes to the richness of the piano sound. Two notes will never sound exactly the same, even with an elite player.
So, the effect is certainly present and unavoidable. The frequency decay is surely significant and easily detectable by a good electronic tuner. But the transient phase is much complex and our brain considers it as an essential component of the piano signature.
Regards
Angelo

so may be the decay is not the good term.

the projection of tone signs the good coupling.

tuning late in time allow to manipulate a little the attack but it can be taken in account sooner hopefully (if the tuner does not bang brutally on the keys).



the display of the ETD, , the way it "replace" the ear of the tuner is where most evolving can be done in my opinion.

when a good tuner is tuning aurally while looking at an ETD at some point he have to decide to follow his ears or the ETD, it is too tiring and time consuming to double check .

the ETD propose his own logic, (based on what is generally admitted as "tuning theory"). That is acceptable to the tuner. but the result in the end is too often deceiving, despite evenness or other qualities, the acoustic of the instrument is not taken in account enough IMO.

high quality unison save the object somehow, but the pleasure to play a piano tuned by a very good tuner is not as with ETD tunings.

having an ETD allow to work consistency, then it is an excellent tool to learn to tune aurally.

the difference between ETD and aural is small, I even wonder if it can be visualized.

may be because the human listening and its curve is not taken in account when programming ETD's , then octaves types are used despite what the instrument is really creating, then sometime references are took with pitches we don't care for.

Most tuners just take things like this in stride and worry about life's bigger problems like, will the lady be able to find her checkbook, and did I close the car windows before this storm started?

sure !

Acappello, I often see the effect on a specific partial which the ETD targets and it is not always even across the keyboard and rarely shares similarities across brands and types of pianos. RCT handles the issue partly by having a short delay after the attack before its starts listening on samples. The two things I do to mimick this are to wait a bit on the ETD when tuning and to adjust the spinner sensitivity accordingly. The lower sensativity seems to filter out the central part of the shift and lets you concentrate on the less variable part of the tone. I liken it to a form of averaging which is probably what the human ear does when faced with the same thing.