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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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Functions of Sound in the Theatre
Music Effects Reinforcement
3 main categories
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Functions of Sound in the Theatre
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Functions of Sound in the Theatre
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.
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Functions of Sound in the Theatre
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Frequency
Which is the higher frequency?
The Nature of Sound
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
The Nature of Sound
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Pure tone
Harmonics
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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…
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Basic Sound-System Configuration
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Basic Sound-System Configuration
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Basic Sound-System Configuration
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Basic Sound-System Configuration
Adding an equalizer into the system for recording and playback
Recording Playback
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Basic Sound-System Configuration
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)
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Basic Sound-System Configuration
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Recording system
Planning a Theatre Sound System
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Playback system
Planning a Theatre Sound System
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Reinforcement system
Planning a Theatre Sound System
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Sound-System Equipment
Loudspeakers & Speaker Systems
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Loudspeakers & Speaker Systems
A Pressure Driver…
Must be used with a horn to disperse the sound
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Loudspeakers & Speaker Systems
A variety of acoustical horns for use with
pressure drivers…
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Speaker Cabinets
Radiation characteristics of various speaker types…
Cabinets are designed to compensate for these variances…
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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)
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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…
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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!
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Mixer
A block diagram of mixer operations
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Mixer
Mixers can be used for both recording and
playback…
Allows you to send a stereo feed into your
recording device from multiple inputs…
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Mixer: Block Diagram for playback & reinforcement
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Sound-System Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Computer
The heart of most theatre systems
Used in every function – recording, playback, editing, storage, and show control
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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…
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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…
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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…
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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)
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Microphones
Handheld microphone
Wireless microphone
PZM (pressure
zone microphone)
Recording and Playback Equipment
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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!
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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!
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
The Sound Booth
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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!
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Speaker Hook-up Methods
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Low-Voltage Systems
Need to wire speakers in a variety of ways to make most of power issues
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
Speaker Hook-up Methods
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
Low-Voltage Systems
Need to wire speakers in a variety of ways to make most of power issues
Wired in combination
Uses both serial and parallel wirings
To determine impedance, use
formulas from both styles of wiring where
applicable
Speaker Hook-up Methods
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Speaker Hook-up Methods
Theatrical Design and Production
Chapter 19: Sound Design and Technology
© 2006 McGraw-Hill. All right reserved.
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
Speaker Hook-up Methods
Theatrical Design and Production
Chapter 19: Sound Design and Technology
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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!