Theatrical Design and Production Chapter 19: Sound Design and Technology © 2006 McGraw-Hill. All...

Theatrical Design and Production

Chapter 19: Sound Design and Technology

© 2006 McGraw-Hill. All right reserved.

Sound Design Today…

Sound design used to be relatively simple…

Specific effects, occasional music, some reinforcement

Now sound is an integral part of the design process…

Credited by USA (United Scenic Artists)

Improvement in equipment and technology has made sound more integral and more available

Film and television have raised audience expectations as well




Functions of Sound in the Theatre

Music Effects Reinforcement

3 main categories





Music

Historically preshow, intermission, & postshow

Comedies historically less music than tragedies/dramas

Modern expansion Themes for characters and/or scenes Constructed sound – Any sound effects created by editing, manipulating, or changing previously recorded sounds Lyrics allowed when appropriate

Focus on supporting psychological intent





Effects

Sole effects – dog bark, phone ring, doorbell – used to be designer’s focus

Effects now create a backdrop for scenes – layered effects to create an environment

Some effects can be created and/or manipulated by a synthesizer…

Synthesizer: A musical instrument that creates sounds electronically, can be used to create a close facsimile of instrumental, natural, or vocal tones.





Reinforcement

Whenever artificial means are needed to boost the loudness levels of actors’ voices – often balancing acoustics of room with voices and/or music…

Terminology –

Acoustics: The sound-transmission characteristics of a room, space, or material; also, the science that studies these qualities

Balance: To adjust the loudness and equalization levels of individual signals while mixing, to achieve an appropriate blend




The Nature of Sound

Sound is a pressure wave that moves at 1,130 feet per second (in air and at sea level)

A pressure source compresses air – the compression wave travels through the air until it strikes a receptor

The human ear is a receptor – it converts the mechanical force of the compression wave into a neurological impulse which is sent to the brain and then interpreted as particular tones and qualities




The Nature of Sound

Frequency

The rate at which an object vibrates – measured in cycles per second

(hertz or Hz)

The pitch of a sound is the characteristic tone produced

by an object – higher pitch = higher frequency

Average Human hearing range: 20 – 17,000 HzHuman with good hearing: 15 – 22,000 Hz




Frequency

Which is the higher frequency?

The Nature of Sound




The Nature of Sound




Intensity

Synonymous with loudness (amplitude)

Loudness can change without effecting pitch

Loudness is measured in decibels

Decibels (dB): A unit for expressing the intensity of sounds; an increase or

decrease of one decibel is just about the smallest change in loudness that the

human ear can detect.

The Nature of Sound




The relative loudness of certain sounds…

Measured in dB

Jet plane at 100 feetThreshold of pain

Loud rock band at 5 ft

Thunder

Loud street traffic at 5 ft

Normal conversation at 5 ft

Quiet street noiseQuiet residence

Quiet whisper

Threshold of Hearing

130

120

110

100

90

80

70

60

50

40

30

20

10

0




The Nature of Sound

Timbre

Distinctive quality of a sound that makes it unique (qualitative)

Based on harmonics of the sound-producing body

Pure sounds rarely occur in nature – most natural sounds produce a variety of overtones

Pitch = the fundamental / base frequency

The amplitude or loudness of each harmonic is less than that of the fundamental – the amount of each harmonic is determined by the physical structure of the source

Harmonics: Frequencies that are exact multiples of a fundamental pitch or

frequency




Pure tone

Harmonics




The Design Process in Sound Design

Commitment

Analysis – Consider various questions from budget to schedule to the script & production needs

Research – Both music and sound effects – know why each cue is in place – psychological and desired impact!

Incubation – Let the design sit unattended

Selection – Pick each specific cue

Implementation – Record the cues and build them into the space

Evaluation




Basic Acoustics

Acoustics: The science that studies the absorption and reflection of sound

In theatre – focus on understanding how stage and audience space acoustics affect the audience’s hearing and understanding of the sound (language & music) of the play

A room’s shape vitally affects the reflection of sound…

Reverberation (reflection in a series of echoes) causes garbling of the sound – parallel walls generate large amounts of reverberation

However, music likes reverberation while voice does not – contrasting needs for contrasting agendas




Acoustic balancing for both speech and music is a great challenge which more and more theatres are attempting to do by using

acoustically adaptable auditoriums…

Shape and materials used in theatre architecture impacts the acoustics of the performance space…

Basic Acoustics




Acoustic Balancing

A well-balanced room for speech has a decay time of ¼ to ¾ second…A well-balanced room for music has a decay time of ¾ to 1 ½ second…Compromise with acoustically adaptable rooms…




Sound Production

1960 to early 1990’s – analog recording with the tape deck

1980’s – introduction of CD technology & the move to digital

Digital age also supported by the growth of computer technology – rise of technology signals the end of the tape era in most theatres

Tape – analog – ‘softer’ sound – hands on editingCD – digital – crisper sound – shift to digital / visual editing

Tape deck: A magnetic-tape transport mechanism used to record an electrical signal on magnetic tape; also used to play back that signal;

does not contain playback amplifier and speaker




Basic Sound-System Configuration

Sound is picked up by a transducer Transducer converts the sound from mechanical energy into electrical energy

Transducer sends signal to a storage device to be recorded or stored





Terminology

Transducer: A device that converts energy from one state into another

Microphone: A transducer used to convert sound waves into electrical energy

Amplifier: Device used to boost the signal received from a transducer to a level that will drive a loudspeaker

Loudspeaker: A transducer used to convert an electrical signal into mechanical energy





Signal sent from storage device to an amplifierAmplifier increases the power of the electrical signal so it can drive a

loudspeakerLoudspeaker converts energy from electric to mechanical/acoustic





Terminology

Tone: A generic term referring to the intensity of the component frequencies contained in any particular sound

Equalizer: a.k.a. EQ An electronic device that selectively boosts or attenuates specific frequencies or ranges of frequencies

Playback System: Devices used to play recorded sound, usually composed of some combination of turntable, tape deck, CD player, computer, equalizer, amplifier, and speaker

Preamplifier: A device that boosts the level of a signal, without alteration or reshaping, to the requisite input signal level of the next piece of equipment in a sound system

Graphic EQ: An EQ with individual slide controls affecting specific segments – so called because interface displays picture of the equalization of full spectrum





Adding an equalizer into the system for recording and playback

Recording Playback





Creating a basic stereo system for recording / playbackStereo (or more) systems are common – recreates a more

lifelike sense of sound and spaceStereo is most commonly thought of as left (L) & right (R)




A graphic equalizer – Note the two separate levels (stereo signal)Also note how the controls create a visual (graphic) representation

of the wave form as it is affected by the EQ





Planning a Theatre Sound System

A basic sound system –

Must consider input (devices for recording)

Must consider output (devices for playback)

Must consider reinforcement (devices for amplification)

Speakers, amplifiers, mixers (controls sound routing), CD players, computers, tape decks, microphones…

The list can be endless – consider what your theatre needs to accomplish and what types of productions it does




Recording system





Playback system





Reinforcement system





Sound-System Equipment

Loudspeakers & Speaker Systems

Loudspeaker = transducer that converts electrical into mechanical energy

Signal activates electromagnet

Electromagnet generates magnetic field

Field causes voice coil to vibrate

Vibration causes speaker cone to move, generating sound






Terminology

Woofer: A low frequency speaker, with a frequency range from 20 to approx. 150-250 Hz

Mid-range Speaker: A speaker designed to reproduce the middle range of audible frequencies – roughly 200 – 1,000 Hz

Tweeter: A high-frequency speaker, generally designed to reproduce from approx. 1,000 to 20,000 Hz

Pressure Driver: A unit housing a large magnet that vibrates a very thin metallic diaphragm to create mid-range and high-frequency sounds

Horn: A dispersion device attached to the front of a pressure driver to direct the sound emitted by the driver into a specific pattern





A Pressure Driver…

Must be used with a horn to disperse the sound






A variety of acoustical horns for use with

pressure drivers…





Speaker Cabinets

Speaker cabinets not only protect the coil, they provide a reverberation surface for sound, changing the loudness and timbre of the sound…

As the speaker works, it causes air compression –

the cabinet amplifies these waves depending on how it is designed





Speaker Cabinets

Radiation characteristics of various speaker types…

Cabinets are designed to compensate for these variances…





Speaker Cabinets

Finite baffle (Inefficient – airtight enclosure)

Bass-Reflex Enclosure(Port in front to allow frequencies produced on the rear compression to come out in phase with those from the front compression)

Ducted Port(Port like bass-reflex but specifically tuned to a particular frequency range)





Crossover Network

Optimum speaker performance is gained when a speaker is working with a specific range of frequencies –

To aid the speaker in working efficiently, a crossover is placed to filter out unwanted frequencies in the electrical signal

Crossovers make sure that woofers receive low frequencies, tweeters receive high frequencies, and so on…





Power Amplifiers

The sole reason for the amplifier is to boost the low-voltage input signal received from an input source to a high-voltage signal capable of driving a loudspeaker…

Two switches – on/off and loudness…

Power needs must be matched by amplifiers – Check you RMS rating to be sure you know the power-load you are working with

Amps impact the clarity and quality of the sound!





Equalizers

EQs boost or attenuate portions of the signal to affect the loudness of specific segments of the sound spectrum…

Analog EQ – older style EQ less used now

Graphic EQ – Graphically displays the equalization of the full spectrum

Parametric EQ – Similar to the graphic EQ but works with different controls – often used for balancing sound during playback in an auditorium





Preamplifier

An electronic device that raises the output of a low-level signal so that it can be read and processed, without distortion, by the next piece of equipment in the sound system. Most mixers require that devices come into their system at line-level (approx. .75 to 1 volt) – preamps boost signals such as microphones or turntables to that level…

DJ PreMic Pre





Mixer

Device designed to mix the output of a variety of sources and route the blended signal on to other devices – one of the most important tools!!!

Digital Mixer

Analog mixer





Mixer

A block diagram of mixer operations





Mixer

Mixers can be used for both recording and

playback…

Allows you to send a stereo feed into your

recording device from multiple inputs…





Mixer: Block Diagram for playback & reinforcement





Patch Bay:

Allows for cross-connection of various pieces of equipment

Outputs and inputs are attached to corresponding receptacles on the patch panel – A patch cord is used to connect the output of one piece of equipment to another





Recording and Playback Equipment

Both analog and digital are in use – Digital is taking over slowly

Show control allows multiple digital devices to be controlled from one main computer – controls sound, lighting, stage effects, etc. using MIDI




MIDI

a.k.a. Musical Instrument Digital Interface was developed in the early 1980s to allow synthesizers to communicate…

MIDI is a standard digital protocol for transmission of data – communication language for sound equipment!

Computers are the top of the digital food chain, controlling other devices that have MIDI capabilities…

MIDI has allowed show control to develop and flourish in live performance





Computer

The heart of most theatre systems

Used in every function – recording, playback, editing, storage, and show control





Digital Audio Tape (DAT)

Cassette tape-based recorders – work much like videocassette recorders rather than traditional analog tape recorders

Allows the addition of a marker so an operator can quickly find needed tracks

Drawbacks – Temperamental in nature Tape is fragile





Compact Disc (CD)

Standard storage device for the industry

Audio information is stored in binary code – A series of reflective & non-reflective surfaces

Uses a laser to ‘read’ the disc

Main reason for dominance – cost & equality

CD-R vs. CD-RW





MiniDisc

Originally a consumer product – now available in theatre

Easy to mark

Allows for record / erase of entire disc or individual tracks –

Tracks can be reordered / added / removed

Drawbacks – Not a reliable playback source for production Difficulties with re-recorded discs





Digital Cartridge Machines

Digital versions of the NAB analog cartridge machines developed for broadcast

Compact & silent machines Start instantly Allows for marking to label the cartridge Automatically re-cue themselves

Disadvantage: Requires one cartridge per cue

Now – software called WaveCart that mimics this for computer systems





Tape Deck

Analog reel-to-reel decks were old standard

Still exist in some theatres so it is good to know how to cut tape and repair these machines

Slowly being replaced by digital alternatives in most cases…





Microphones

Microphones convert mechanical sound waves into electrical energy

They are used for recording and reinforcement in performance

Microphones can alter the frequency, timbre, and dynamic range (loudness variations) when converting the sound…





Microphones

Carbon Microphone

Uses granules of carbon to generate the electrical signal

Mouthpiece in telephones – rugged but with very narrow frequency response

Not used much in theatre





Microphones

Crystal Microphone

Uses piezoelectric crystals – certain crystals produce voltage when pressure is applied…

Very rugged but limited frequency response – usually found in less expensive tape recorders

Not used much in theatre





Microphones

Ribbon Microphone

Uses a thin corrugated strip of metal vibrating between two magnetic poles – vibration generates voltage…

Very good frequency response but very delicate mic

Often used inn radio broadcasting – adds color and warmth to the voice…





Microphones

Dynamic Microphone

Uses a small coil with an electrical charge – pressure strikes the diaphragm – coil moves up and down in response – movement induces an electrical current

Very good frequency responseRugged

Workhorse of the theatre





Microphones

Condenser Microphone

Electrically complex

Diaphragm is placed parallel to a charged plate – changes in the space between the two results in voltage shifts, translated as electrical signal

Excellent frequency response Requires a power supply to keep the

plate charged Requires some care in handling





Microphones

Pick-up Patterns

Omni-directional – spherical pattern from the mic head

Bidirectional – Figure 8 pattern (ribbon mics)

Directional –

Cardioid – heart-shaped Hypercardioid – More directional cardioid

(Shotgun mic)





Microphones

Wireless Microphones

Does not require a cable to connect to mixer or other equipment

Signal is broadcast by a low-power FM transmitter to a reciever and then is fed to mixer

Requires battery power to power the transmitter

Can also receive other broadcast signals on receiver

Expensive to get high quality - $1,000 - $3,000 per mic

Commonly used to reinforce shows





Microphones

Handheld microphone

Wireless microphone

PZM (pressure

zone microphone)





Sound Equipment Maintenance

Never eat, drink, or smoke in the booth or around the equipment (or any electronic equipment!)

Cover all decks, amplifiers, etc. with cloth dust covers when not in use

Store all microphones in a padded surface cabinet

Coil all microphone and speaker cable and hang on peg board when not in use

Inspect connectors before and after each use to insure proper working order

Never blow on a microphone to see if it is working – speak or gently snap your fingers!




The Sound Booth

Used to facilitate the recording and playback of cues during production

Design is personal but should be efficient and logical…

Usually an enclosed space so recording can be done

If reinforcement is the main goal of design, consider a house mix position to allow operator to hear the show from audience space – improves balance and focus of the sound mix!




The Sound Booth




Rehearsal and Performance Procedures

Follows the same path as lighting

Media is intangible so requires clear & concise instructions for all involved

Notes must be taken on equipment and cues in a manner that allows for adequate ‘reproduction’ which matches technical rehearsals




Playback Layout Pattern

Sound is only noticed when a mistake is made!

Cues must happen in a routine fashion so prepare for the production

Name cues appropriately

Number cues in sequential order to avoid confusion

Always make a backup after any changes to keep a good copy of the show at hand!

Rehearsal and Performance Procedures




Practical Considerations

Preamp and Power-Amp Output

Mic-level – low voltage ( 1 to 750 millivolts) produced by microphones, turntables, and other gear

Line level – dynamic voltage level used between various pieces of equipment in the system

Power level – higher voltage level produced by amplifiers to drive speakers

Power amps range between 1 and 35 volts output – careful hook-up required not to destroy equipment!




Speaker Hook-up Methods

Low-Voltage Systems

Best practice to match the impedance of a speaker with the output impedance of an amplifier

Impedance: Resistance in an

AC circuit – measured in ohms

Output terminal 8-ohm speaker hookup




Low-Voltage Systems

Need to wire speakers in a variety of ways to make most of power issues

Wired in series

S + S = circuit impedance

8 + 8 = 16 ohms

Simply add the speaker impedance together





Low-Voltage Systems


Wired in parallelS + S = circuit impedance N N

8 + 8 = 16 = 8 = 4 ohms 2 2 2 2 2Speaker impedance is added together and then divided twice by the number of speakers in use





Low-Voltage Systems


Wired in combination

Uses both serial and parallel wirings

To determine impedance, use

formulas from both styles of wiring where

applicable





Low-Voltage Systems

In general…

Speakers wired in parallel have a cleaner sound than speakers wired in series

Series wired speakers have a loss of clarity and quality

Most amps can drive mismatched loads but be careful damage when driving too much or too little

Impedance matched to load will result in best performance & quality





High-Voltage Systems

Standardized at 25 and 70 volts

Advantages:

-Effectives solution for large number of speakers on same system

-Transmit signal over long cable run with less loss of quality

-Reduce effects of inductive interference

Often used in monitor systems





Balanced vs. Unbalanced Lines

Unbalanced

Often used to hook-up equipment in booth – short runs with low

magnetic interference

Balanced

Used with microphones to keep induced interference to a

minimumCosts more!

Theatrical Design and Production Chapter 19: Sound Design and Technology © 2006 McGraw-Hill. All...

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Transcript of Theatrical Design and Production Chapter 19: Sound Design and Technology © 2006 McGraw-Hill. All...