In a message Canadian Guy writes:

> If you are musical, you will recognize that the common machine speeds are
> those of the human voice pitches.... as opposed to working around high
> speed electric or gas motors that need to be geared down to working tool
> speeds, and whose high speed gearing adds another aggressive noise.   The
> high pitched whine makes you tense and you weary sooner.

I can remember it clearly, even though it was a dozen years ago, when my
children were still little.  I was coming up the subway stairs (the same ones
I would come up after the World Trade Center collapse) at 86th and Lexington.
 There were guys in those beige denim overalls cutting out the sidewalk
around the subway ventilation grates - the steel grates had rusted, popping
up and creating a trip hazard, and these guys were using gas concrete saws to
cut around them, before they lifted the old grates out.

I watched them work, and I saw - or rather heard - that it formed a sort of
urban symphony, the repeated, random, intermittent rising and falling whine
of the saw as the operator dipped in and then dipped out of the concrete.  As
a contrapunto, I heard for the first time (just like the echos in the
snowbound canyons of a New York blizzard) the waxing and waning of the
traffic - a roar when the light turned green, rising to wind tunnel
proportions as the bulk of the traffic went through, tailing off in an adagio
and diminishing to a sort of quiet idle when the light turned red.  Then
there was the minor movement, the crosstown traffic on the east-west street,
which repeated the rhythm of the major movement, but piccolo.

I pass that corner every few days; the concrete and steel is old now and
stained, but I always hear the music.       Best,  Christopher