- I need more reverb on those drums.
"In The Air Tonight".
("In The Air Tonight" by Phil Collins)
♫ I can feel it coming ♫
- Human beings can intuitively recognize
the physics of music.
Whether it's sound waves, compression, frequencies,
resonance or tones,
we know it when we hear it.
What we're actually recognizing though,
is the science of how sounds move
from one place to another.
Here's five basic connections between
music and physics that explain what we're hearing.
(bells chiming)
Sound is made of different types of waves
traveling through a medium,
whether it's a gas, solid, or liquid.
They're created by vibrating objects
like when a speaker moves outward and inward,
pushing and moving away from the air next to it.
Imagine, for instance, Survivor's
"Eye of the Tiger" playing.
And that part where it goes...
("Eye of the Tiger" by Survivor)
It's booming through the speaker.
The air molecules rebound
with more than their normal energy and speed,
transported as mechanical waves.
Essentially controlling these various sound waves
is how we make music.
And, you know, rise up to the challenge of our rivals.
(chuckles) Am I right?
♫ It's the eye of the tiger
♫ It's the thrill of the fight
♫ Rising up to the challenge of our rivals
♫ And the last known survivor
♫ Stalks his prey in the night ♫
- Okay, so that speaker?
For a moment during its vibration,
it has a greater than normal concentration
of air molecules in the region next to it.
This is a region of compression that moves outward
as the energy from those molecules is transfered
to others farther and farther away from it.
These regions are naturally louder spots near the speaker,
while the spots where the music is softer
are regions of rarefactions.
And when regions of compression and rarefactions
come together,
there's almost no sound at all.
Dead spots like these can actually be designed
into buildings by architects,
especially when they use materials
like wall padding that absorb sound waves.
Each compression in the following rarefaction
makes up what we call one cycle.
(instrumental piano of "Eye of the Tiger" by Survivor)
These cycles are important,
because by measuring how many occur in a single second,
we can determine the sound wave's frequency.
This indicates how rapidly or slowly the medium is vibrating
as the wave passes through it.
Especially when you're listening to something like
"Life in the Fast Lane" by the Eagles.
("Life in the Fast Lane" by the Eagles)
Hertz is the unit of measurement we have for frequency.
For instance, a single vibration per second is one Hertz.
Human ears are constructed so that they're really good
at hearing fluctuations in frequency,
detecting sounds as low as 15 Hertz
and as high as 20,000 Hertz.
We refer to these high and low ends as pitch,
and when you play specific frequencies together,
they can create appealing sounds.
For instance, if there are two waves
and the second has twice the frequency of the first,
we denote this as a ratio of two to one,
also known as an octave.
(dramatic vocalizing over rock music)
(vocalizing high notes)
With instruments, you can create
all kinds of different ratios,
blending together the sound waves
to make music that'll...
♫ Surely make you lose your mind. ♫
(ball thumps against wall)
♫ Life in the fast lane, yeah
♫ Life in the fast lane
♫ Everything
♫ All the time
♫ Life in the fast lane
(vocalizes guitar parts)
("Life in the Fast Lane" by the Eagles)
What's also important about frequency is that
every material, whether it's wood, glass or even steel,
has a natural frequency at which it vibrates in resonance.
Putting energy into any substance
at its resonant frequency will force it to vibrate.
When we're making music with instruments,
the shape, size, and material determine
what sounds it can create.
Consider the--
(guitars play)
horn section in Bob "The Siege" Seger's
"Shakedown".
("Shakedown" by Bob Seger)
The sound waves that fit inside
subsequently resonate and get louder.
That's why tubas resonate at low frequency--
(playing low notes on tuba)
while something like a piccolo resonates at a
high, piercing frequency.
(playing high notes on piccolo)
(dramatic violin music)
Remember, all of this comes back to sound waves.
Similar to waves in the water,
they can collide together into forms
with even lower depths.
In music, this is called a standing wave,
and it can be controlled in a consistent manner
with an instrument to make a tone that repeats
a specific frequency,
or a small number of related frequencies.
This effect is when we start categorizing sounds
as musical notes.
Basically, they're the tones that our brains
find the most pleasing.
For example, Slash's amazing guitar solos in
Guns N' Roses "November Rain".
("November Rain" by Guns N' Roses)
So, a C note, you know...
♫ Doe, a deer
♫ A female deer ♫
Is a frequency of 264 Hertz,
while F, or...
♫ Far, a long long way to run ♫
Is 352 Hertz.
And those tones that we find unappealing,
well, those thousands of random combinations of frequencies
are what we call plain old noise.
(uplifting piano music)
So what's your favorite song?
Mine is "Mandolin Rain" by Bruce Hornsby,
cuz man, that emotion.
It's amazing.
Anyway, let us know your favorite in the comments
after you visit our original article at howstuffworks.com
about ten connections between physics and music.
And get on that frickin' reverb.
(laughing)
♫ Surely make you lose your mind ♫
(ball thumps against wall)
(laughing)
- [Voiceover] You missed.