What's a squillo, and why do opera singers need it? - Ming Luke

Gripped with vengeful passion,

The Queen of the Night tears
across the stage.

She begins to sing her titular aria,

one of the most famous sections from
Mozart’s beloved opera, The Magic Flute.

The orchestra fills the hall with music,

but the queen’s voice soars above
the instruments.

Its melody rings out across thousands
of patrons,

reaching seats 40 meters away— all
without any assistance from a microphone.

How is it possible that this single voice
can be heard so clearly,

above the strains of dozens
of instruments?

The answer lies in the physics of the
human voice,

and the carefully honed technique
of an expert opera singer.

All the music in this opera house
originates from the vibrations

created by instruments—

whether it’s the strings of a violin
or the vocal folds of a performer.

These vibrations send waves into the air,
which our brains interpret as sound.

The frequency of these vibrations––

specifically, the number of
waves per second––

is how our brains determine the
pitch of a single note.

But in fact, every note we hear

is actually a combination
of multiple vibrations.

Imagine a guitar string vibrating at its
lowest frequency.

This is called the fundamental,

and this low pitch is what our ears
mostly use to identify a note.

But this lowest vibration triggers
additional frequencies called overtones,

which layer on top of the fundamental.

These overtones break down into specific
frequencies called harmonics, or partials–

and manipulating them is how
opera singers work their magic.

Every note has a set of frequencies that
comprise its harmonic series.

The first partial vibrates at twice the
frequency of the fundamental.

The next partial is three times the
fundamental’s frequency, and so on.

Virtually all acoustic instruments
produce harmonic series,

but each instrument’s shape and material
changes the balance of its harmonics.

For example, a flute emphasizes the
first few partials,

but in a clarinet’s lowest register,

the odd-numbered partials
resonate most strongly.

The strength of various partials

is part of what gives each instrument
its unique sonic signature.

It also affects an instrument’s ability
to stand out in a crowd,

because our ears are more strongly
attuned to some frequencies than others.

This is the key to an opera singer’s power
of projection.

An operatic soprano—the highest
of the four standard voice parts—

can produce notes with fundamental
frequencies

ranging from 250 to 1,500 vibrations
per second.

Human ears are most sensitive to
frequencies

between 2,000 and 5,000
vibrations per second.

So if the singer can bring out the
partials in this range,

she can target a sensory sweet spot
where she’s most likely to be heard.

Higher partials are also advantageous

because there’s less competition
from the orchestra,

whose overtones are weaker at
those frequencies.

The result of emphasizing these
partials

is a distinctive ringing timbre
called a singer’s squillo.

Opera singers work for decades to
create their squillo.

They can produce higher frequencies

by modifying the shape and tension
in their vocal folds and vocal tract.

And by shifting the position of their
tongues and lips,

they accentuate some overtones
while dampening others.

Singers also increase their range of
partials with vibrato––

a musical effect in which a note slightly
oscillates in pitch.

This creates a fuller sound that rings
out

over the instruments’ comparatively
narrow vibratos.

Once they have the right partials,

they employ other techniques to
boost their volume.

Singers expand their lung capacity and
perfect their posture

for consistent, controlled airflow.

The concert hall helps as well,

with rigid surfaces that reflect sound
waves towards the audience.

All singers take advantage of these
techniques,

but different vocal signatures demand
different physical preparation.

A Wagnerian singer needs to build up
stamina

to power through the composer’s
four-hour epics.

While bel canto singers require versatile
vocal folds

to vault through acrobatic arias.

Biology also sets some limits—

not every technique is feasible for every
set of muscles,

and voices change as singers age.

But whether in an opera hall or a
shower stall,

these techniques can turn unamplified
voices

into thundering musical masterpieces.