Temperament and inharmonicity may be separate phenomena, but they certainly come into play with each other. Your octave from 440 to 880 may actually be from 440 to, say, 881, due to inharmonicity, so every interval in between is affected. By ear, you are tuning so that the relationships between intervals are correct, that is, so that there is the proper relationship between the way that the intervals sound. If an ETD only deals with the pitch numbers, it may be correct by the numbers, but the relationships won't be right.
I don't even bother much with counting beats exactly when I tune. I'm not good at judging fractions of a second, and the beats vary from piano to piano. The temperament on a cheap spinet is not the same as that on a concert grand. But it's no big deal to get the intervals correct on both of them. (It's usually easier on the concert grand, though!)

I won't jump in the middle of the ETD vs Aural debate. I've had tuners that use an ETD (Accutuner) and tuners that do it by ear only. I will say that I have been most pleased/satisfied with tunings done by aural-only tuners.

I would also point out, fwiw, that in Germany I have not met a tech that uses an ETD. They are all of the old school over here I guess.

But I'd also note that technology/design improvements in ETD in recent years has been pretty impressive. I'm talking about the Verituner specifically. It will not, imho, replace aural checks/tweaking but it has a lot of potential to save the tuner's ears for where they are really needed. And that's why I think that this particular ETD is gaining acceptance on this side of the pond. Several highly regarded technicians in the BENELUX have started to use it and spread the word. Whether their enthusiasm will sway their conservative, hide-bound colleagues to the east remains to be seen.

It will be interesting to see if Verituner's competitors can come up a design that will take ETDs to the next level.

JP

Just what am I supposed to be saving my ears for, if not for tuning?

If you don't tune by ear, you aren't getting practice listening.

As far as I am concerned, saving my ears means leaving when the sound is too loud. If it were too loud when I'm tuning by ear, it would be too loud if I were tuning with and ETD.

(I've got two shows tomorrow before the play-offs of my bocce league, where my team went from dead last in the first half to tied for first in the second half. Maybe the play-offs are important, but not as important as the shows, and I don't need to save my ears for them. )

If you take the double negative here literally, this is true. If what Norbert means is that no concert tuners on any of the world's major stages use machines, that is absolutely false. There are many tuners regularly tuning for major pianists on the world's major stages absolutely using the Reyburn cyber tuner and the accutuner. I don't know any using the verituner, but it wouldn't surprise me. I don't know what the percentages are, but a concert tuner using a machine is not an annomaly.

Jim Coleman and Virgil Smith had a contest at a PTG convention a few years ago. Jim,tuning electronically, beat Virgil, tuning aurally. The next year Virgil won. The pianos were voted on by several tuners and pianists. Jim is also an excelent aural tuner and teacher as is Virgil.

Keith:

At least in Europe it's apparently a total no-no.

Perhaps over here it's different.

It's not a battle for me.

I don't even tune myself.

But I can tell when the tuning is good and - holds!

norbert

I dont think the relationship between machine, and aural tuning staying in tune, is relevant. Hammer technique, pin setting, and string rendering, are what keeps a piano tuned. If those cant be done solidly it wont matter what you use for temperment and octaves , unisons and so on.