Digital audio
is a highly sophisticated technology.
It pushes the envelope of many diverse
engineering and manufacturing disciplines.
Although the underlying concepts have been
well understood since the 1920s,
commercialization of the digital audio
did not begin until the 1970s.
Because theory had to wait 50 years for
technology to catch up,
the complexity of digital audio is all the more
reason to begin the discussion with the basics.
Once we understand the nature of sound,
we can begin to explore ways to encode the information contained in an audio event and process it and store it digitally.
It would thus be a mistake for the study of digital audio technology to forget
the acoustic phenomena for which technology has been designed.
Music is an acoustic event.
Whether it originates from the instruments
radiating in the air
or from the direct creation
of electrical signals,
all music ultimately finds its way into the air,
where it becomes a matter of sound
and hearing.
It is therefore appropriate to briefly
review the nature of sound.
Acoustics is the study of sound
and is concerned with the generation, transmission,
an d reception of sound waves.
The circumstances for those three phenomenons are
created when energy causes a disturbance in the medium.
For example, we put something back into the
beat, that is back into the bass, that is back in,
The place I'm always at
And I'm taking the stage
When I'm happening in your face
Now I'm laughing, give me space
Cause I'm crashing in the thoughts
That I'm having, yo
The thoughts that I'm having
Won't leave my face, leave me grasping
While I ought to be blasting
out your ass
I'll send you back and I'm taking you out
With the trash,
cause there's no doubt
My shit is fat
When I'm breaking it, taking it nice
So be sure to pay attention
Pay attention
The kettle drum is struck
It is a drum head that disturbs the surrounding air,
the medium.
The outcome of that disturbance is the sound
of the kettle drum.
The mechanism is simple.
The drum head is activated and
vibrates back and forth.
When the drum head pushes forward,
air molecules in front of it are compressed.
When it pulls back,
that area is verified.
Disturbance pressure consists of regions above and
below the equilibrium isomospheric pressure.
Nodes, they define areas
of minimum displacement.
and the antinodes are areas of maximum,
positive, or negative displacement.
Displacement is quite small.
In normal conversation,
particle displacement is about one millionth of an inch.
A crowd's acoustic outpouring might
cause displacement of one thousandth of an inch.
Sound is propagated by air molecules through this excessive
displacement that corresponds to the original disturbance.