1. Sound Design and Technology (Sound Systems)
There are three basic types of sound systems used in theatre:
Sound reinforcement
Sound recording
Sound playback
Much of the same equipment is used in all three configurations, just arranged in slightly different order.
Microphone – a transducer that converts sound waves into electrical energy.
Transducer – a device that converts one form of energy into another
A microphone is a type of transducer. It picks up sound and converts it into a weak electrical signal.
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2. Sound Design and Technology (Sound Systems)
The signal from a microphone is sent to a preamplifier in the mixer.
The preamp boots the power of the signal to the line level for signal processing by the mixer.
Preamplifier – a device that increases the power of a weak signal for use by subsequent stages in the electronic circuit.
Mixer – a device used to combine two or more input signals to create a blended output signal. Multichannel mixers blend numerous input signals and routes them to multiple output channels.
Line level – the standard operating voltage used by mixers and signal processors.
Signal processing – the manipulation of transducer input signals to change, blend, and enhance the resultant output signal(s).
The flow chart of a basic, single-channel sound reinforcement system.
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3. Sound Design and Technology (Sound Systems)
After the sound has been processed, it is sent to the power amplifier.
The power amp substantially increases the power of the signal and sends it to the loudspeaker.
Power amplifier – a device used to boost the signal received from the mixer to a level that will drive a loudspeaker.
In a recording system, sound is sent from a microphone/input  mixer  computer (Digital Audio Workstation, or DAW).
In live recording, very little processing is used in order to preserve the original sound.
In a playback system, sound is sent from a DAW  mixer  Amplifier  Loudspeaker
A diagram that includes all three systems in one: reinforcement, recording, and playback.
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4. Sound Design and Technology (Sound Systems Components)
There are three basic types of microphones used in theatrical sound design.
Ribbon microphones use an extremely thin strip of metal suspended between poles of a magnet to transduce sound.
The air pressure of the sound waves moves the metal ribbon back and forth, generating electrical energy.
They are extremely delicate and are typically only used for recording or in the pit orchestra.
Dynamic microphones consist of a magnet surrounded by a wire coil.
One end of the coil is attached to the mic’s diaphragm. When sound waves strike the diaphragm, the diaphragm and coil move and create electrical energy.
These mics are rugged and suitable for onstage use.
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5. Sound Design and Technology (Sound Systems)
Condenser Microphones are the most electrically complex mics used in theatre sound.
The diaphragm is made of thin conductive material and forms one plate of a capacitor.
Capacitor – an electronic component composed of two conductive places separated and insulated from each other. Used to store an electrostatic charge.
A constant voltage (v48 aka “phantom power”) is applied across the capacitor plates.
When a sound wave hits the diaphragm, the pressure changes the space between the two plates. This alters the voltage and creates electrical energy.
Phantom power – a method of supplying DC power through the microphone cable to operate condenser microphones.
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