…in which I will relate sound to frequency to pitch to note
(B-Mus, U Texas, 1972)
One Tuesday morning, taking a break on my sunny deck, I sat listening to the sounds that emanate from or descend upon Diamond St. Valley (new name). These are sounds that most of us hear, but don’t always identify, recognize, or really care about. Suddenly, I realized that these are mostly a form of music.
What follows is neither a music nor physics lesson, only an attempt to appreciate sounds that we hear, and give them some relation—physics, frequency and to music, pitch. I’ve been surrounded by music all my life, but never had really related it to the “noises” all around us. Most of us don’t have a piano or other musical instrument, but likely you may find here in your surroundings a relation to the sounds you hear.
I quickly realized that most of the sounds we hear relate basically to electrical voltages with frequencies with which you are no doubt familiar: 110 volts and its multiple, 220 v. Lets try to relate frequency to music and to all those other sounds. Those of us who have ever been at a piano have heard of ”middle C”. This note is pitched slightly below the “A” at 440 cps (cycles per second). Obviously. 220 and 110 are even fractions of these–also known as “octaves”– eight “white” (piano scale) notes below.
[Please excuse my use of piano as a reference—guitars, violins, and trumpets don’t quite have the necessary layout that a keyboard does.]
While tumbling in my mind these relatable numbers, I received the Ahah! moment. I realized the source of the hums that we hear from nearly all electrical implements are quite close to these frequencies—and can be related to musical notes or keys on a piano. Right in the center of the piano is
“middle C”, and we can relate most of our pitches to this—two keynotes down is B flat. The most common sound of electrical engines is “B flat” or about 110 cps. Listen to your refrigerator or other steadily-running appliance hum. (Not a computer, which varies.)
Now that the relationships are established, we can hear the Diamond Valley sounds much more in context.
It’s Tuesday and the loudest hum is that from the engine that powers those large sweeping brushes that clean our streets. It roars to D above middle C, then calms way down several notes while resting.
Suddenly there’s an overpowering siren starting low in pitch rising to a high B flat then descending. “THIS IS A TEST…” I forgot, It’s Tuesday noon.
OK, time to listen carefully and selectively: Jet planes: jets and accelerating engines hum up and down the scale but vary also in volume. Approaching jets are about “D” on the piano, approaching us increasing in pitch to about “F”, then fading. Remember those TV demos that show a car approaching with horn blaring, then lowering in pitch as it passes? The approaching sound vibrations are reaching us faster as the source nears, then fades downscale.
Then there’s prop planes, car & truck engines and horns, buses, dogs (large & small), J-Church’s ding-a-ling bells, carpenters’ and roofers’ saws, hammering, loud voices, chain saws, traffic hums on 280 and San Jose, birds (ravens, hawks, hummers, robins, pigeons, etc.), kids, dog barks (their fixed pitches vary with size), the wind in the trees, most human voices (which are in the middle range of about 2 octaves).
You can sometimes hear the CalTrain whistle at the Bayview stop. When breezes are from the east and all else is pretty quiet, listen very carefully for the “D” toot of the Bay Bridge foghorn—about every 20 seconds.
Without realizing it, we are accustomed to these sounds, largely because either they are infrequent, or they are in the lower ranges of sound–we are accustomed to the hum of the city—at least in Glen Park.
What is annoying are those that get our attention — pavement breakers, shouts, bangs, thunderclaps, and nearly all high pitches: brakes, shrieks, squeals of school kids (well, some), whistles, sirens.
Fortunately, there are some things that we seem to have largely avoided here in Diamond Valley– horn-blowing, loud radios, hot-rodders, gunshots, raucous shouting.
A few musicians have picked up on the sounds of the city—mostly our horns (like Chevrolet’s C#,E,G,A), but also other sounds and whistles. There’s Muni, which has a hard time finding an attention-getting horn–loud, recognizable, but not blasting.
Remember, it’s all in the pitch and volume.