It can be, my sentiment is that we maintain the pitch high , pushing the tone toward the partials, when tuning the 2 other strings to avoid that.
If unisons are tuned dull then the sound is less clear.

Not less long but allowing less dynamics in my opinion, which is the same thing in the end.


That play with the phase came from Japan

Sorry for what youy wrote RXD, I certainly dont remùind having disclosed any personal exchange, if I did it was not volontarely (I am very attentive to that usually, so your remark bothers me)

When I talk of something said by someone I say who (cite the source) and I don't use things that are in the personal circle usually.


If an unison is tuned pure, it is nicely sounding, the same if it is "perfectly tuned"

I am of the opinion that unisons should be tuned as pure as possible. I believe that the color and "life" to the sound of a piano have more to do with the temperament and voicing of the hammers. That is one reason why I get bored with the sound of a piano tuned in ET. You might try experimenting with different temperaments. I personally like the EBVT3. It really opens up the sound of the piano. Different keys will have different personalities. You just might be surprised at what you hear.

Alas, I've just tuned a piano on Saturday, but will only return to it in March with a re-glued damper head (the owners are out for a few weeks).

But in my (limited) experience, the M3, M10 and M17 with a common lower note have very similar beat rates. (If anything, I seem to find that they increase slightly, but that might be my limited tuning skill.)

So, I presume that your test for a flat unison looks as follows:
1) Use the test unison as the top note of a M10.
2) Compare the beat rate of this M10 with that of a M3 and M17 using the same lower note, i.e. check whether the test unison slots neatly half-way into the double octave.
3) If the M3 and M17 both beat faster than the M10, the test unison has slipped flat.

Am I on the right track?

Yes.

If you compare intervals like that using a single string (by muting out the rest) against more than one string and the beat rates change, you know the unison is off.

Beat rates cannot be precisely evaluated , they ony can be compared, and they wave in speed, so a global listening is better than being too picky on them.

Comparaison between single strings and unison beat rates is even more uneasy. But it is easy to compare the tone and the consonance in the matched partials at large just activity and spectra enrichment is enough, hopefuly. (once an octave is tuned the FBI are tested in case of doubt, usualy consonance is enough to keep consistence in my opinion)

I forget to say, I find difficult to listen and analyse other tuners unisons (deconstruct them) First I must be in front of the piano (recordings give an idea of the shape of the envelope but can be misleading) , second the main thing I notice is how much attack is allowed, which is he only parameter that can be adressed in the end.

Some of my colleagues exactly think the same, saying "I prefer a bit more of attack" for instance (more percussion).

Then , when one is practically constructing tone he obviously use all means availeable, as the sound return from the room, and a deconstruction of the spectra.

A tuner that does not create tone is just missing the point, but, I agree that at some point unisons are simple and so evident any remaining problem is due to voicing (old strings, soundboard tiredness ,etc;)

The instrument the place and the pianist/music dictates what kind of tone is expected.

A light regulation tweak may be enough to change the emphasis on the attack or on the sustain.

In "Pianomania" the tuners is a little exagerating, asking what kind of tone projection Pierre Laurent Aymard wish ? an intimate enclosed tone or a full projecting tone, He said that so to show what a tuner can eventually do, I am not sure it is a question having so much importance for the pianist before a concert.
But PL Aymard rightly send the ball back to the sender bu answering "both" ! (and I give him right in that case)

Anyway, a high level professional pianist can play on all kind of pianos, and will adapt his playing so to be in phase with the instrument. ATworst even uneveness of tone is adresses, after a few rehearseal moments , the mental map is engraved.

Any remaining problem is then asked for correction (and this is really rare unless in recording studios, that the pianist ask for some voicing or a few notes corrections, most of the time he does not even meet the tuner, unless that last is asked to stay so sometime a post it, but concert grands are kept at concert level so they can be choosed before the concert)

the range of "tone opening" among tuners is in my opinion quite large. but the process occur between fundamental and the remaining spectra.