It is with some trepidation I'd like to introduce myself to such an
experienced and knowledgeable group as this, but I'll try nonetheless,
as there's a pressing question I'd like to put out to the group.

To start at the beginning, I was born within walking distance of the
Brentford Musical Museum, and have fond memories of visits there in the
1970s with my grandparents.  I may be imagining it when I remember my
grandfather saying that while player pianos may be cheap to buy, they
were impossible or expensive to restore.

Fast-forward to 2008, and I found myself on sabbatical in the USA,
after 14 years working with wind tunnels at the University of Surrey.
The sabbatical transitioned to full-time life in Colorado, and purchase
of a house, whose over-wide hallway begged the purchase of a piano.
A search of Craigslist turned up a $200 player piano, which for $210
(for two sets of piano movers) later, made it into our house. It took
two teams of movers since the first had to abandon it in the garage, it
being heavier than they expected.

Another $50 later (a bargain!) it was tuned, after 30 years of neglect,
the tuner estimated.  It's in need of regulation, a few notes don't
sound, and the bellows barely hold five seconds of vacuum when plugged
off, but it can play a tune, and it hasn't been wrecked by previous
restoration.

It turns out, once I found out what I'd bought, the heaviness was to
be expected -- the piano is a Farrand Cecillian, with the Bush & Lane
3-row cast metal unit-valve stack, which alone is apparently a 2-person
lift.  It's been re-tubed in the past, in clear plastic (vinyl?)
tubing, but is otherwise untouched.  I'm looking forward to a careful
and gentle restoration, once all the other jobs-around-the-house are
done.  Controversially, I may consider testing some "modern" materials
(RTV, neoprene, etc.) but only if totally reversible, and on the basis
that the unit-valve construction is amenable to "trialling" materials
on individual valves.

My pressing question is unconnected to the player piano; it is a
fascinating problem at work, concerning what might be a giant organ
pipe, which may be of interest to the group.  My company has been
engaged to solve the problem of a building complex, which in a wind of
sufficient strength, from a particular quadrant, whistles extremely
loudly, with extremely clear tones.  I have established that the tones
shift with temperature, to the correct degree as to be expected by the
change in the speed-of-sound, and so I'm confident(?!) the tone is
aero-acoustic, not mechanical.

At low wind speeds, for a typical temperature, a 787 Hz tone is evident
in spectra, though perhaps not audible.  At sufficient wind speeds, loud
tones are present at 636 Hz and 477 Hz, sometimes separately, sometimes
together, perhaps dependent of precise speed or direction, but that's
not yet proved.  The sound reverberates between the parallel glazed
faces of two buildings, approximately 95 feet apart.  A 318 Hz tone has
also occasionally been observed in spectra, and many other lesser
intermittent peaks have been seen.

The values 633:477:318 show a clear 4:3:2 ratio, and 787:636 is almost
5:4.  I was greatly excited to find a slot 108 mm deep all up one
corner of the building, where there would be substantial airflow --
perfect, as a quarter-wave tube, to produce 787 Hz.  There are no
obvious, credible, necked cavities to act as Helmholtz resonators.

My questions are: (1) could such a slot sound sub-harmonics, such as
the 636 Hz and 477 Hz observed?  I believe a stopped pipe should only
produce odd harmonics; (2) How can a fourth and third harmonic exist
in isolation, with no sign at all of the implied fundamental?  I'm
aware of the use of "resultant tones" to simulate extremely low notes,
but I don't think the building was designed to be an organ!  All my
searches for "missing fundamental" have led in the wrong direction --
the suggestion of a low note by generating just its harmonics, not the
accidental generation of harmonics absent a fundamental.

I do hope these questions are not entirely out-of-place on this list;
perhaps I've been looking at the problem too hard and think it's more
interesting and relevant than it is?

Again, I feel privileged to belong to a list written and read by such
interesting and knowledgeable people,

Yours humbly,

Tom Lawton