Transcript Lecture Set I - Introductory Concepts

Week 1.2
Some Math
Last Session
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Elements of Music
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Structured/Designed Sound
 Some pleasant – bells, most musical instruments
 Some nasty – whip
 Some intermediate - drums
Rhythm (time)
Tones (Not defined, though)
Loudness (not actually listed, nor defined)
Pleasurable ????
Message ????
We listened to some interesting samples of music.
We will be listening to much more.
Bone Flute – Music is older
than I am!
40,000 years or more
Neanderthal
Where did instruments come
from???
What does this mean?
Lightening

Takes time to get to you or you are in big
trouble.
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Speed = distance/time
What is distance?
What is time?
Sound --- A “disturbance”
Important Definitions

Length or Distance
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How “far” something moves or travels.
Measured against some agreed upon standard.
Length Standard .. The Gorf
1
2
Unknown Length = 4
3
1/8 Gorfs
4
1/8
The real standard:
Systems of Units

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SI Units …. Meters, Seconds,
Newtons/Kilograms
English System ….. Feet/yards,
seconds, pounds/poundals
More Important Definitions
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TIME
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The subjective “distance” between two EVENTS.
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Original Clock – The Earth’s Rotation
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It needs to be objective … ie measurable and
reproducible.
“It is two days journey”
Today’s Clocks –

“He ran the race in 4 hours, 2 minutes and 21.85
seconds”
Things that “tick” at some rate



The planet … once a day
The Pendulum .. Depends on a number of
things;
Parameters:
Mounting
Length
Weight,
whatever
that is.
In case you care
period  2
Length (L)
acceleration of gravity (g)
  3.1415926
g  32 ft / s 2
We will discuss this “g-thing” when we
get to acceleration.
Sun Clock
Water Clocks
And so on …
Rolex (~$10K)
Atomic Clock (NASA) $ megabucks
The music clock:
the Metronome
112 quarter notes per minute.
We hear music (and other
noise) in our ears.
Sound
And you didn’t even know that
you have one!
Sound pushes against
your
Tympanic Membrane
Better View
Inside your head
D
d
To Brain
A graph … what does it all
mean?
distance (meters)
100
snail
50
rabbit
1
time (seconds)
2
Another Graph .. a biggy!
1.5
disturbance
1
0.5
0
0
5
10
15
-0.5
-1
-1.5
Time (seconds)
20
25
Important Definitions
The PERIOD, T is the time it takes to go from one condition to the next time
that exact condition is repeated.
The frequency, the number of oscillations per second, is given by:
1
frequency 
period
or
1
f 
T
Siren … a scientific instrument
The Graph
1.2
"airspeed" - relative
1
0.8
0.6
0.4
0.2
0
-0.2
0
2
4
6
8
Time in milli-seconds
10
12
Bottles on the wall …
Loudness
Resonance (later)
Rotational
Speed
(Turns/second)
Helmholtz Resonators
Helmholtz’s Results
Note from Middle C
C
D
E
F
G
A
B
Frequency
264
297
330
352
396
440
496