2. Sound Waves
Generation and Propagation
Sound wave = changes in pressure caused by
vibrating object
Compression = High pressure
Rarefaction = Low pressure
Sound needs a medium to “vibrate”
Usually air, but could be anything
Speed of sound depends upon the medium
Air = 1130 ft/sec Water = 5000 ft/sec Steel = 13000 ft/sec
3. Measuring sound waves
Sound waves are longitudinal waves
Vibrating object compresses the air around it.
Pushes air away leaving an area of low pressure
Vibrating object then compresses more air to create a
“chain”
4. Measuring methods
Cycle
A single push and pull of the vibrating object
One are of compression followed by one area of
rarefaction
An initial increase in atmospheric pressure from the
norm, followed by a drop below the norm and then a
return to normal
Mathematically displayed by a sine curve
Pressure on Y axis
Time on X axis
5. Measuring methods
Period (T) and Frequency (f)
Period - The time it takes to create one cycle
Frequency - The number of cycles in one second
1
f
T
=
Measured in Hertz (Hz) or cycles per second
7. Measuring methods
Frequency will determine pitch
High frequency = high pitch
Low frequency = low pitch
Octave – a doubling of halving of the
frequency
8. Measuring methods
Human hearing range
Low range between 15 to 30 Hz
With enough power lower than 15 Hz can be felt, but
not heard as “sound”
High range varies with age and gender
Women - up to 20 kHz
Men – between 15 to 18 kHz
High frequency range will lower with exposure to high
levels of sound and age
9. Tuning
Traditional orchestra would tune First Chair Violin A first.
Remaining instruments would tune relative to that
A above middle C was tuned to about 420 Hz
As halls grew larger it was found to be desirable to tune sharper
1939 A was established to be 440 Hz
Corresponds to the 49th
key on a full size piano
Tuning is not a science. The relative frequency difference is
what is important
10. Measuring methods
Wavelength
The distance from one area of compression
to the next or one area of rarefaction to the
next v
f
λ =
l=wave length
V = velocity of sound in medium
usually 1130 ft/sec
f = frequency
11. Measuring methods
Amplitude
How high the pressure goes above and below
normal atmospheric pressure
Corresponds to how loud the sound is
“loudness” is relative to frequency and dependant
on the listener.
12. Timber and Harmonics
Harmonics – multiples of a base frequency
Timber – the characteristics of a particular sound or
instrument
Different harmonics combined in different levels
13. Physics of Sound
Part 2
Basic Acoustics
Inverse square law
Reinforcement/cancellation
14. Interference
Phase
measurement of where the amplitude of a wave is
relative to another wave
A cycle can start at any point in a waveform
Two waves with the same frequency can start at
different times
Measured as an angle in degrees
Related to the sine wave representation of the wave
16. Beats
Happens when two
slightly different
frequencies interfere
Often used in tuning
17. Standing waves
When sound waves bounce off
of obstructions, they can
interfere with themselves
Tends to reinforce some
frequencies and attenuate
others
Prevented by using
Non- Parallel walls, ceilings
Convex surfaces
Multi-level ceiling sections
18. Reverberance (Reverb)
Consisting of multiple, blended sound images caused by
reflections from walls, ceilings and other structures which do not
absorb sound
NOT echo
Echo consists of individual, non-blended sound images
Reverb time is related to
The time it takes for a sound to reduce to an inaudible level
Loudness of sound relative to background noise
Ratio of loudness of reverberant to direct sound
Short reverb time (less than 1.5 sec) is better for speech or
drama
Long reverb time (more than 1.5 sec.) is better for music
19. Absorption
Controlling reflections can reduce or increase reverb
time
Air tends to absorb frequencies above 2K Hz
Sight line obstructions
Frequencies above 10 kHz tend to not bend around
corners well or other obstructions
l=1.3 inches for 10 kHz tone
Frequencies below 1kHz do very well
l=5.65 feet for 200 Hz tone
Specialists are often hired to “tune” a space
acoustically
20. Acoustic attributes
Defined by Leo Beranek after a 6 year study
of 54 concert halls
Used to define acoustic properties in terms
that other trained professionals can
understand
21. Acoustic attributes
Intimacy – Indicates the size of a room
How it sounds to the listener, not actual size
Determined by the initial-time-delay-gap (ITDG)
Interval between the sound that arrives directly at the
ear and the first reflection
Usually considered to be the most important
attribute
22. Acoustic attributes
Liveness
Related to Reverberance
Room size is related
More reflections is live. Less reflections is dry or
dead
Warmth
More low frequency sound relative to mid
frequency
Too much low frequency sound is said to be
“Boomy”
23. Acoustic attributes
Loudness of direct sound
Inverse square law
Loudness of sound will decrease by one quarter
every time the distance from the source is
doubled
Definition or Clarity
Good definition when sound is clear.
Related to intimacy, liveness, loudness of direct
and reverberant sound
24. Acoustic attributes
Brilliance
A hall that has liveness, clarity and intimacy
Diffusion
Relates to the orientation of reverberant sound
Where is the reflected sound coming from
It is preferable to have reverb sound coming from
all directions
25. Intensity
Like pitch, loudness is a sensation in the
consciousness of a listener
To produce a sound twice as loud requires 10
times the power
Inverse square law
Sound level is reduced by a factor of the square
of the distance away from the source
If you move double the distance from the source, the
sound intensity will by one quarter
26. Intensity
Intensity is a measurable quantity
SPL – Sound Pressure Level
dB – deciBel
A system of measuring a ratio between two powers
1dB change – Imperceptible change
3dB change – Barely perceptible
5dB change – Clearly noticeable
10dB change – About twice as loud
20dB change – About four times as loud
27. dB SPL Sound
150 dB Jet engine at 1m
140 dB Rock and Roll stack at 1m
130 dB Thunderclap, Air Raid Siren 1 Meter
120 dB Jet takeoff (200 ft)
110 dB Rock Concert
100 dB Train passing up close
90 dB Heavy traffic
80 dB Hair Dryer
70 dB City street
60 dB Noisy bar or restaurant
50 dB Open plan office environment
40 dB Normal conversation level
30 dB Library, Soft Whisper (5 Meter)
20 dB Quiet domestic environment
10 dB Broadcasting Studio, Rustling Leaves
0 dB Threshold of hearing in young adult
28.
29. Sound Envelope
Listener does not hear individual cycles of sound waves
Attack – Time it takes for sound to rise from nothing to its
greatest intensity. Usually short.
Decay – Time it takes for a sound to fall from its attack level to its
sustaining level. Decay time is usually short
Sustain – The time during which the initial vibrating source
continues to supply energy to the sound. Usually perceived as
the duration and intensity of the sound
Release – Time it takes for the sound to drop from its sustain
level to inaudibility after vibrating object stops supplying energy
31. Interaction of Sound
with other Show Elements
Script
Identification of motivational cues - sounds listed in
the script (cues that actors react to)
Identification of environmental cue opportunities –
locations, time of day, season, era,
Identification of emotional cue opportunities – What
do you want to say about actor, situation. . .
32. Interaction of Sound
with other Show Elements
Acting
Collaborate on what is “heard” on stage - Actors
need to understand what sounds are part of the
physical environment shared with the set and props.
Some sounds are there for them to react to (Motivational)
Some sounds need to be originated by a performer’s
action (ring a bell, turn on a radio, etc...)
Monitoring of stage action to off-stage locations
Placement of wireless mics and stage monitoring /
fold back
33. Interaction of Sound
with other Show Elements
Costumes
Musicals – wireless mics that need to be
accommodated within costumes and hair
Scenic
Location of on-stage devices (speakers, mics)
Collaboration on scene shifts (needs/opportunities to
cover transitions using sound cues – “Functional”
sound cues)
Identification of cues that support each other (sound
used to reinforce scenic element that would normally
make noise (car, train station, rain, etc. . .)
34. Interaction of Sound
with other Show Elements
Props
“Active” on-stage devices that may be props
Lights
Identification of cues that support each other
Thunder and lightning,
Day time or night time,
Lights used to represent outdoors and other items/times
that would normally have a recognizable sound associated
with it.
Identification of transitions where cues should go
together
35. Interaction of Sound
with other Show Elements
Music direction
Vocal reinforcement (micing)
Music reinforcement (micing, direct feeds and
mixing)
Vocal/music monitoring for performers and/or band
Choreography
Music cues
Reinforcement of foot fall (Mic cues for tap dancing)
Music monitoring for dancers
36. Interaction of Sound
with Other Show Elements
Stage Management
Cueing
Monitoring of stage action to booth
Intercom systems
37. Use of Sound in the Theatre
What Audience Hears – Company Hears
Elements that are part of the show
What an audience hears.
Cues, Aural Reinforcement
Support for the Overall Production
What the company hears
Monitoring, Communications
Recording
38. Use of Sound in the Theatre
What Audience Hears – Company Hears
Sound Cues - “created” sounds that
advance the story
Sound effects, music transitions and underscoring.
Produced / reproduced through mechanical or
electronic means
Mechanical – real sounds (sheet metal for thunder, crash
box for breaking glass, ½ coconuts for horse galloping,
actors making bird calls)
Also called practical
Electronic reproduction
Sounds stored as signals on CDs, Minidisks,
computer files
39. Use of Sound in the Theatre
What Audience Hears – Company Hears
Reinforcement of aural elements of
production
Mic cues for vocal and musical performance
Orchestra Mics
Instrument direct feeds
40. Use of Sound in the Theatre
What Audience Hears – Company Hears
Monitoring – Providing performers and members of the
company a portion of the sound from the performance to assist
with their performance.
Stage monitors for singers to hear the band – and
themselves – Fold back
Pit monitors for band to hear vocals – and themselves
House monitoring for crew positions, back stage and
dressing rooms so company can hear “what’s going on”
41. Use of Sound in the Theatre
What Audience Hears – Company Hears
Communications
Intercoms for cueing and communications among the
company
Recording
Live feeds of performance for film, video and audio
recording
42. Paper work, paper work, paper
work….
CUE DEVICE INPUT CH LEVEL DEVICE OUTPUT CH LEVEL FADE TIME NOTES
SUFFOLK COUNTY COMMUNITY COLLEGE
SOUND CUE SHEET
Show:_________________________________________ Sem / Year _____/_____
Page _____ of _____
43. Paper work, paper work, paper
work….
CUE # Sound Cue Placement PG. Type Location
A Preshow music At house opening 7 Called Cluster / BOH
B Preshow announcement with house to half 7 Called Cluster
C Preshow fade with blackout 7 Called Cluster / BOH
D Narrator with lights up 7 Called Cluster
E "Loser" with lights up 9 Called USC
F music cut Chuck: "…the fuck!" 9 Called USC
G Awesome sound Agnes: "Go." 13 Called cluster
H Mission Impossible theme Agnes: "…the intro music!" 14 Called cluster
I music cut ??? 14 Called cluster
J Narrator TOS 18 Called cluster
K T.V. with lights up 18 Called USC
L T.V. fade Tilly: "…not good at all." 19 Called USC
M magic Agnes: "What are you doing?" 23 Called cluster
N fight music Chuck: "…what happens next - " 24 Called cluster
O music cut end of fight 24 Called cluster
P Narrator into LL Cool J Lilith: "…kicketh some ass." 26 Called cluster
R "Waterfalls" with lights up 28 Called cluster
S Voice Over Tilly: "…Let's do this!" 29 Called cluster
T magic missle with spell 29 Called cluster
U Farrah explodes Farrah: "Oh no." 29 Called cluster
V Cheerleader enterance Agnes: "…would be a bad thing, right?" 34 Called Cluster
W music cut 34 Called Cluster
X cube eats Steve: "…oh neat, a jello mold!" 47 Called USC
Y cube transforms Tilly: "…call it Miles." 49 Called Cluster
Z "Gonna Make you Sweat" Chuck: "…Cheerleaders!!!" 59 Called Cluster
AA Footsteps with blackout 69 Called SL
BB Tiamat Roar 69 Called SL
CC Tiamat fight 69 Called SL
DD Curtain call with lights up 71 Called Cluster