BTW are there just two - Rainer and I - who think the low E flat of Monica's grand out of tune?
Monica has said she doesn't think her Eb sounds out of tune, and I therefore believe that it almost certainly isn't.
In fact, if I listen to the recording while mentally trying to block out the RH chords and the LH off-beat E flats, focusing only on the LH low notes, the intervals of fourths and fifths in the sequence of alternating A flats and E flats sounds perfectly OK, including the low Eb. But if instead I focus more on the RH and the chord harmony, there is a slight sense of the low Eb not quite fitting with the remainder of chord in which it appears, even though there is no obvious reason to suspect the intonation of the higher chord notes.
So we have a mystery. The low Eb is both in tune and out of tune at the same time! The solution? Well, I think it could be related to the fact that piano tuners generally apply stretch
to compensate for inharmonicity
. This means octaves are tuned slightly wide of pure, to make them sound more in tune. But this can cause problems (as it evidently has here) with very big intervals of more than 2 octaves. The chord which is causing the problem here has a 3 octave separation between the low Eb and the Eb in the RH chord. One would expect, at that sort of distance, the intonation discrepancy from cumulative stretch to become noticeable.
Does this make sense?