Capturing the Magic of Time

The graceful motion of a swinging weight on a string has fascinated people since ancient times. While there were scattered attempts throughout the millennia to make the novelty of a pendulum do something useful, until around 1600, when Galileo described the physics of a pendulum, there was no meaningful way to put the pendulum to work. But, after Galileo pulled back nature’s curtain, the pendulum became the engine of the wind-up clock and the dictator of time in music.

Putting the Pendulum to Work

During the Renaissance pendulums were used to do various tasks including as a sort of kinetic battery to energize pumps to lift water out of coal and tin mines. But the major application of the pendulum during the Baroque period was the mechanical clock. The pendulum clock (think of a Grandfather Clock) was the world’s time keeper for three centuries. During the 1930s physicists discovered that time could be accounted for by the vibration of a crystal under electrical pressure. That discovery began the inexorable hike to digital time keeping.

The motion of a pendulum is described by its “period”. That’s the amount of time between the two maximum arc points of the pendulum. For musicians the “period” is the time between the clicks of the metronome. Or, more commonly described as “Beats Per Minute”. Or just BPM.

E pur si muove

Galileo was among the first philosophers (we call them physicists and mathematicians today) to assert that the laws of nature were mathematical. The famous quote attributed to him “Yet it still moves”, became a credo for scientific thinkers. It was their way of saying to the all-powerful church, “Think what you want and require others to follow. But the reality of nature does not yield to church dogma.” The Inquisition condemned Galileo for “vehement suspicion of heresy" because he asserted that the Earth revolves around the Sun. More than three centuries after the Inquisition made its decision, Pope John Paul II acknowledged that the Inquisition had been wrong.

Galileo ‘s breakthrough understanding of the motion of a pendulum produced one of the most famous, and useful, formulas in basic science:

T = 2π √L/g

Time (the period or BPM) = 2 x 3.14159 x square root of the Length of the String (L) divided by the acceleration of gravity (g). On earth, g is roughly equal to 32.17 feet per second.

Galileo’s insight was that the period of the pendulum is defined by gravity and the length of the string used in a pendulum. Long strings make for slow time and tempo. Short strings make for fast time and tempo. A pendulum always takes the same amount of time to complete its swing.

Gravity matters… a lot. On Earth the value of the constant “g” is roughly 32 feet per second. So, if you set up a pendulum on your next trip to Mars, where the value of “g” is 38% lower than it is on Earth, you’ll find that the same weight and string length will produce a BPM that’s 38% slower than your Earth-bound pendulum.

Although Galileo stripped away the magic of a pendulum’s motion, harnessing the period of a pendulum to become the metronome took a very long time. About two hundred years.

But first, a little bit about Galileo’s dad……. Galileo’s father was Vicenzo Galileo. The senior Galileo played the lute and made important discoveries about the physical nature of vibrating strings as related to pitch and tension. Vicenzo Galileo is regarded as one of the thinkers who created the music of the Baroque period. He is certainly one of the creators of music theory. Indeed, he and a few other intellectual titans of the age really did invent modern opera. In their minds, they were recreating Greek drama in the way it was performed in Athens during Classical times.

Birth of the Music Metronome

Back to the metronome…..The first functional metronome designed for musicians was created in 1815. Johann Nepomuk Maelzel of Germany is widely accepted as inventor. The details of Maelzel’s success are available at this link. https://guarnerihall.org/a-brief-history-of-the-mechanical-metronome/

Maelzel was a prolific inventor and friend of Ludwig Von Beethoven. He designed the ear trumpets that Beethoven used to help overcome his encroaching deafness. Beethoven was so keen on Maelzel’s metronome that he began to put numerical tempo markings on his compositions. Then he reviewed many of Mozart’s compositions and put suggested tempo markings on those. Ultimately Beethoven abandoned the effort because he recognized that on any given day he might play a piece faster or slower. The only “correct” tempo is the one that an artist decides upon in the moment. The “correct” tempo is defined by artistic goals, limits of skill and what engages the audience. Choosing the correct tempo for a composition is one of the many reasons that conductors of symphony orchestras are so vital to the success of performances of complex music.

Tempos are a very different matter in Celtic music. Constraints on tempo are greater because jigs, reels, hornpipes, barn dances, slides, slip jigs, strathspeys, ridees and polkas are all dance music. Feet rule! These forms make up the bulk of all session music and recordings of Celtic music. Because these forms are grounded in the experience of dance, the range of tempo options is relatively narrow. A jig may work beautifully at 90 bpm. But, dancers cannot move their feet fast enough to keep up with a jig played at 120 bpm. Leaving aside airs and sean-nós singing, Celtic music is played mostly with tempos ranging between 90 bpm and 130 bpm.

Four Types of Contemporary Metronomes

1. The old-style, wind-up, pendulum metronomes of the Maelzel type. You’ve seen these pyramid-shaped things on pianos, in movies and photos.

2. Digital metronomes. These electronic devices are small, reliable and inexpensive. They are truly everywhere you find musicians. These come in various forms including clip-on or stand-up on a desk.

3. Computer apps. Metronomes for a desk-top computer or a smart phone are widely available, reliable and inexpensive.

4 Voiceless metronomes. These silent metronomes are the latest development. They function by using a small motor inside a phone or wrist watch to vibrate. It is exactly like putting a phone into silent mode and then receiving a call or text. You’ll feel the buzz on the beat. You won’t hear the clicks. The silent metronome is a choice of many drummers because the small voice or click of a standard metronome is lost against the sound level of a drum set or band.

The Value of the Metronome

A metronome helps train a musician to perform accurately at tempos required by the music. In the end, one must remember….An air has to breathe. A jig has to dance. A reel has to rock. Sean Nós has to move the listener….

A core problem with most musicians is that once a tune is learned, the tempo inevitably increases. “Speeding-up” is a common issue in sessions. That’s because the human brain is anticipatory. It’s always trying to guess what’s next. When one player is early with a note, another player’s brain hears that early note and says “speed up…. you are behind”. And, like a snowball rolling down the hill, the session picks up speed.

In dance competition, the dance studio or sponsors set exact tempos for each type of dance. During a session, the fiddler usually sets the tempo.

When players speak about BPM in Celtic music, they sometimes mangle the numbers. Reels are usually noted in 4|4 time signature. Notating music this way results in fewer eighth notes – a cleaner score, easier to read. However, reels are actually played in 2|2 time signature, cut time. That provides two beats per measure. But 4|4 time insists on four beats per measure. If I set my metronome to 120 bpm and play a reel using a 4|4 time signature, I’m actually playing at 240 bpm. To be truthful, I’m not playing at all. 240 bpm does not support the music, dancers can't dance and my hands certainly don’t move that fast.

What’s a Musician to do?

The answer to the question of what bpm to set is….. there is no answer. Johannes Brahms, Felix Mendelssohn Giuseppe Verdi and Richard Wagner all refused to employ metronomes. Beethoven eventually renounced the metronome. What’s a traditional, Celtic musician to do?

Aim for a tempo of 120 bpm during practice sessions. You’ll build confidence into your playing and be prepared to deliver a rock-solid pulse for most Celtic music. When you are comfortable, in control and accurate at 120 bpm, you’ll be ready for most sessions.

Using a metronome will lift the veil hiding the magic of time in music. And peeking at magic always makes the world a more beautiful place.