0:00:07.249,0:00:09.069
Gripped with vengeful passion,

0:00:09.069,0:00:11.859
The Queen of the Night [br]tears across the stage.

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She begins to sing her titular aria,

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one of the most famous sections [br]from Mozart’s beloved opera,

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"The Magic Flute."

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The orchestra fills the hall with music,

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but the queen’s voice soars above [br]the instruments.

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Its melody rings out [br]across thousands of patrons,

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reaching seats 40 meters away—

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all without any assistance [br]from a microphone.

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

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above the strains [br]of dozens of instruments?

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The answer lies in the physics [br]of the human voice,

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and the carefully honed technique [br]of an expert opera singer.

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All the music in this opera house [br]originates from the vibrations

0:00:51.898,0:00:53.458
created by instruments—

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

0:00:57.615,0:01:02.746
These vibrations send waves into the air, [br]which our brains interpret as sound.

0:01:02.746,0:01:04.706
The frequency of these vibrations––

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specifically, the number [br]of waves per second––

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

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But in fact, every note we hear

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is actually a combination [br]of multiple vibrations.

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Imagine a guitar string vibrating [br]at its lowest frequency.

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This is called the fundamental,

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

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But this lowest vibration triggers [br]additional frequencies called overtones,

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which layer on top of the fundamental.

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These overtones break down [br]into specific frequencies

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called harmonics, or partials—

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and manipulating them [br]is how opera singers work their magic.

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

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The first partial vibrates [br]at twice the frequency of the fundamental.

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

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Virtually all acoustic instruments [br]produce harmonic series,

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

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For example, a flute emphasizes [br]the first few partials,

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but in a clarinet’s lowest register,

0:02:17.614,0:02:21.344
the odd-numbered partials [br]resonate most strongly.

0:02:21.344,0:02:23.064
The strength of various partials

0:02:23.064,0:02:27.064
is part of what gives each instrument[br]its unique sonic signature.

0:02:27.064,0:02:31.217
It also affects an instrument’s ability [br]to stand out in a crowd,

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

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

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An operatic soprano—

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the highest of the four standard [br]voice parts—

0:02:44.797,0:02:47.627
can produce notes [br]with fundamental frequencies

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ranging from 250 to 1,500 vibrations [br]per second.

0:02:53.047,0:02:55.737
Human ears are most sensitive [br]to frequencies

0:02:55.737,0:02:59.737
between 2,000 and 5,000 [br]vibrations per second.

0:02:59.737,0:03:03.657
So if the singer can bring out [br]the partials in this range,

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

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Higher partials are also advantageous

0:03:10.817,0:03:13.537
because there’s less competition [br]from the orchestra,

0:03:13.537,0:03:16.817
whose overtones are weaker [br]at those frequencies.

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The result of emphasizing [br]these partials

0:03:19.497,0:03:24.889
is a distinctive ringing timbre [br]called a singer’s squillo.

0:03:24.889,0:03:28.469
Opera singers work for decades [br]to create their squillo.

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They can produce higher frequencies

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

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And by shifting the position [br]of their tongues and lips,

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they accentuate some overtones [br]while dampening others.

0:03:42.536,0:03:46.556
Singers also increase their range [br]of partials with vibrato—

0:03:46.556,0:03:50.835
a musical effect in which a note [br]slightly oscillates in pitch.

0:03:50.835,0:03:53.415
This creates a fuller sound [br]that rings out

0:03:53.415,0:03:56.685
over the instruments’ [br]comparatively narrow vibratos.

0:03:56.685,0:03:58.355
Once they have the right partials,

0:03:58.355,0:04:01.803
they employ other techniques [br]to boost their volume.

0:04:01.803,0:04:05.803
Singers expand their lung capacity [br]and perfect their posture

0:04:05.803,0:04:08.433
for consistent, controlled airflow.

0:04:08.433,0:04:10.223
The concert hall helps as well,

0:04:10.223,0:04:14.465
with rigid surfaces that reflect [br]sound waves towards the audience.

0:04:14.465,0:04:17.075
All singers take advantage [br]of these techniques,

0:04:17.075,0:04:21.337
but different vocal signatures [br]demand different physical preparation.

0:04:21.337,0:04:24.152
A Wagnerian singer needs [br]to build up stamina

0:04:24.152,0:04:28.012
to power through the composer’s [br]four-hour epics.

0:04:28.012,0:04:31.612
While bel canto singers require [br]versatile vocal folds

0:04:31.612,0:04:34.413
to vault through acrobatic arias.

0:04:34.413,0:04:36.813
Biology also sets some limits—

0:04:36.813,0:04:39.873
not every technique is feasible [br]for every set of muscles,

0:04:39.873,0:04:42.833
and voices change as singers age.

0:04:42.833,0:04:46.023
But whether in an opera hall [br]or a shower stall,

0:04:46.023,0:04:49.173
these techniques can turn [br]un-amplified voices

0:04:49.173,0:04:51.342
into thundering musical masterpieces.