Weird detuning

[Mark Graham]

I tuned a Mason & Hamlin A grand last Thursday for a longtime customer who
is an excellent pianist. There was a call on the answering machine Friday
that something was wrong with the tuning. I went this morning (Monday) and
found he wasn't kidding. Four notes in the middle were painfully out. On
two of them, one string was fine, one string was grossly flat, and one
string was grossly sharp. One other had the center string grossly flat and
the other two OK. The fourth had one severely sharp string, two others
flat.

The piano is less than 20 years old and well-maintained. The house is
humidified now and air-conditioned in the summer. The plate, bridges,
soundboard, and pinblock all seem fine. I did not test the pins with a
torque wrench, but they felt good and normally tight. The piano tuned up
well. As with most M&H's this section of the piano has one string of each
unison strung singly with a loop around the hitch pin, but I could find
no correlation between that and the way the strings detuned, meaning, I
don't think things slipped around the hitch pins.

The detuning was so bad it could not have been mere carelessness on my
part. The man played it the day I tuned it and it was fine. His
grandchildren and his son were there at different times Thursday and
Friday. His son (grown) is also a good pianist, and told his father it was
out of tune, and lo and behold. The grandkids played it, but didn't abuse
it, and I don't see how this could have happened even if kids did bang on
it.

Frankly, if evidence supported it, I would say someone deliberately
detuned four notes. After all, some strings were severely sharp, more than
50 cents. But there is no tuning lever in the house, nor does the son have
one. The customer said he assumed I had put new strings on and had not
told him. But he said he ruled that out, because I hadn't charged him for
the work, and (gentle dig at me) he knew that was out of the question.

What on earth is going on? I will, of course, monitor the piano, and if it
happens again I know the man will contact me right away. But all I can
come up with is

A) a very strange burglar
B) magnetic anomalies in the earth's crust or core
C) alien intervention
or D) supernatural interference in my life, either simply to annoy me,
or to make me realize that I really have no control over the universe.

I find none of these satisfying, and some of them irritating. The customer
seems quite sane and normal, but I've watched enough Hitchcock movies to
know that you can never REALLY TELL.

Help me. My own sanity is at stake here.
Mark Graham
Baldwin-Wallace Conservatory of Music