I get this question a lot, and
it's a fair question. Because if you've ever listened to bells and
thought they sound kind of off, well... you're right, because they do.
[Music: Bach Cello Prelude] And it's not that bells are out of tune
(although some bells maybe are out of tune, particularly older bells). [Music: old bells] But even perfectly tuned bells can
sound a little bit off. So... why? Well, the answer lies in the
vibration patterns of the bell, and these vibration patterns are pretty
unique. They might mean that a familiar song on bells will sound kind of weird.
[Music: Elton John Tiny Dancer] And this affects not only the sound of the bells,
but also how we perform on the instrument, or how we arrange for the instrument or how we compose.
And it does mean that certain songs will sound a bit better on bells than other songs. [Music:
Tina Turner, What's Love Got to Do With it?] So to understand this we first need to take a look at other instruments and
see how they make their sound. Let's go to a piano. A piano makes it's sound with
vibrating strings. A lot of instruments do. So, when I play a single note on a piano, in this case
a C, I'm hearing that note, that C. But I'm also hearing a number of other higher frequencies
called harmonics, or overtones. Just in this one note I'm hearing a frequency an octave higher,
another C. I'm hearing the fifthm the Gm and then another octave higher another C ,and then a major
third, an E. And actually, I could keep stacking overtones forever. But as we go up the series
these overtones become a little bit less present. So just in that one note we're hearing
all of these harmonics. But are we really hearing that? Our ears maybe can't
pick out every frequency individually, but it's the combination of these
frequencies that yields the sound that we hear, and makes certain
instruments sound the way they do. So why are the harmonics particularly
these notes, or these frequencies, and why not some other notes? Well, it's physics!
When a string vibrates, it oscillates in a wave. And its wavelength is equal to the length of
the string. And the speed at which it vibrates, that's the frequency or the musical
note. Now, if you remember from physics, when a string vibrates, it vibrates at its
wavelength, at its length, but also at all the fractions of its length. So we'll get
an oscillation that's the full wavelength, that's our note. Then half the wavelength,
and at half the wavelength, we're doubling the frequency. Doubling frequency in music means
we're going up an octave, so that's how we get that first harmonic. Then the next fraction
of the wavelength, that's a third, and that fraction corresponds to the second harmonic,
which is the G, the fifth above that octave. And we could go on forever. Now that series
of notes or frequencies is called the natural harmonic series and it holds true for most things
that vibrate: vibrating strings or columns of air. But bells are a fascinating exception. A bell's
vibration pattern can't be visualized by a two-dimensional wave. When a bell is struck,
the entire bell vibrates, and its vibration pattern is really complex. So we don't hear
the natural harmonic series. Instead we hear an entirely different combination of frequencies, and
rather than calling these frequencies harmonics, we call them partials or partial notes. So the
first bell partial is actually an undertone, a full octave lower than the strike tone. So,
if I play this C on the carillon (the same note I played on the piano), we're also hearing
a partial that's a full octave lower than that note. That undertone is called the hum tone.
Actually, the hum tone persists much longer than the strike tone. Listen. Long after the strike
tone has decayed you can still hear the hum tone. The second partial note is the primary
reason that bells might seem out of tune. The second partial is a minor third,
which on the C bell is an Eb. Do you hear it? It's such a strong overtone you
can pick it out if you listen for it. After the minor third, we have a fifth and an
octave and then some higher partials. But it's this minor third that really defines the
sound of the carillon, and of bells. So, if all the physics and harmonics and
frequencies were a bit complicated, just remember that bells are unique because
they possess an inherently minor sound. And this has huge implications. On a piano, we had a
major third overtone, and it was several octaves above the fundamental so it's not very present in
the sound. But bells have minor third overtones, and that overtone is right there, right next to
the strike tone. So bells naturally sound minor. Listen to this. If I play a C major
arpeggio, it sounds a little bit off. But then if I play a C minor arpeggio, it sounds more in tune, because the minor third in
the C bell is amplifying the chord. And that's why songs in a major key on the carillon might sound
a little bit more out of tune [Music: Ode to Joy] But songs in a minor key will sound
more in tune [Music: Asturias Leyenda] But, wait! Doesn't a minor chord
also include a major third? Yes, a minor chord is just a minor third on the bottom
and then a major third on top. So what if we only played minor thirds and stacked them on top
of each other? What would that sound like? That sound is a diminished chord. It sounds
dissonant, yes. Unresolved. But on bells, it's perfectly in tune, and there are actually musical
scales that fully encompass the diminished chord, and they sound really awesome on carillon.
They're different from major scales and minor scales that you're used to, but that's
a topic for a different time. For now, remember that bells are really special and
unique because they possess an inherently minor sound. So the next time someone
asks you if the bells are out of tune, tell them no, they're perfectly in tune, their
vibration patterns are just really awesome. [Music: Tina Turner, What's
Love Got to Do With it?]
