Transcript sci_fair3

Shepard Scale Extravaganza
Seth Simonds
5th Grade Mrs. Wayne
Experimenting With
Shepard Scales
• A Shepard Scale (sometimes called a
Shepard Tone) is an audio illusion that
tricks a person into thinking that the scale
or tone is always either going up or that it
is always going down.
• Question: What is the simplest way to
make a Shepard Scale?
Penrose Stairs
• The Shepard Scale
is very similar to an
optical illusion
called the Penrose
Stairs.
• Pick a corner and
pretend to either
walk up or down.
See how it goes on
and on?
Ascending and Descending
• This is a famous
drawing called
Ascending and
Descending by M.C.
Escher that shows
one set of soldiers
always walking up
and another set of
soldiers always
walking down using a
set of Penrose
Stairs.
Observations and Hypothesis
• A website tool was used to produce a Shepard Scale.
• The data for the notes and the volume of each note was
copied into a table from the website.
• The website tool also allowed the music to be played
faster or slower which had no affect on the audio illusion.
• The website tool also allowed the audio illusion to be
played either ascending or descending and the audio
illusion of going on and on worked for both.
• The Shepard Scale on the website was made using four
scales.
• The hypothesis and experiment is to see if the effect of
going on and on can be done using only two scales.
Materials and Procedures
• Materials
– A website with a Shepard Scale tool
• http://www.netalive.org/tinkering/shepard-effect
– A music keyboard to play music scales
– A computer program to generate a Shepard Scale
• Procedures
– Used the website to learn how Shepard Scales work
• The website used four scales to produce the audio illusion
– Played a music keyboard to learn music scales
– Used a computer program called a Sequencer to
make and manipulate a Shepard Scale with only two
scales
•This is the musical notation for the Shepard Scale.
•This was the scale that the website used to make the audio illusion.
•To create the audio illusion, just play these notes over and over again.
•It uses four ascending scales each starting with the C note.
•To make this presentation easier, only the ascending scales are shown
but it can also work descending too.
•How the audio illusion works is that the Treble Clef (top) notes get softer
as they are played and the Bass Clef (bottom) notes get louder.
•Each of the four scales changes its volume differently.
•See the chart below to see how the volume changes.
Note
Scale 1
Volume
Scale 2
Volume
Scale 3
Volume
Scale 4
Volume
Volume Total
C
0
50
100
50
200
C#
4
54
96
46
200
D
8
58
92
42
200
D#
12
62
88
38
200
E
16
66
84
34
200
F
20
70
80
30
200
F#
25
75
75
25
200
G
29
79
71
21
200
G#
33
83
67
17
200
A
37
87
63
13
200
A#
41
91
59
9
200
B
45
95
55
5
200
•This is the musical notation for the Simpler Shepard Scale.
•The experiment was to see if using half the notes would also give the
audio illusion of going up and up in tone.
•To create the audio illusion just play these notes over and over again.
•It works! The notes sound like they are always going up and up!
•Instead of using four scales to create the audio illusion, this created the
audio illusion with only two scales.
•The same idea is used with the higher line of notes starting loud and
getting softer while the lower line of notes starts soft and gets louder in
volume.
•See the chart below to see how the volume changes.
Note
Lower Pitched Scale 1
Higher Pitched Scale 2
Volume Total
C
0
100
100
C#
8
92
100
D
17
83
100
D#
25
75
100
E
33
67
100
F
42
58
100
F#
50
50
100
G
58
42
100
G#
67
33
100
A
75
25
100
A#
83
17
100
B
92
8
100
Scale 1 continues with the
Scale 2 C note
Scale 2 loops back down
to the Scale 1 C note
Making a Shepard Scale
• It is pretty much impossible to play a true Shepard Scale on a
single piano because it is very hard to play different notes at
different volumes.
• A computer or multiple keyboards have to be used to make
the Shepard Scale because carefully controlling volume is
needed to create the audio illusion.
Using Two Scales to Create A Shepard Scale
100
90
% Volume
80
70
60
Lower
Pitched
Scale 1
50
40
Higher
Pitched
Scale 2
30
20
10
0
C
C#
D
D#
E
F
F#
Note
G
G#
A
A#
B
C
Conclusion


I found out that the easiest way to make a
Shepard scale is by using two notes at a
time that are both the same pitch with
different volumes but it does sound better
with four notes.
However the two scales are much easier
to play and write and it still gives the
sense of going on and on and on.
Data and Graphs
Scale Step 1
Scale Step 2
Scale Step 3
Scale Step 4
Scale Step 5
Scale Step 6
Scale Step 7
Scale Step 8
Scale Step 9
Scale Step 10
Scale Step 11
Scale Step 12
And Now Back to the Beginning