TH 1551
Sound for the Theatre


Devices for converting acoustic energy into electrical energy.

Signal levels

Small signal (impedance) measured in ohms
Low impedance, 30-300 ohms, used almost exclusively in the theatre
High impedance, 50K ohms - 2M ohms, seldom used
Dynamic (preferred) or condenser mikes used in the theatre

Wiring configurations

Unbalanced for high impedance mikes - no shield required
Balanced for low impedance mikes - shield required.
Three wire male XLR connectors standard in the theatre


Omni-Directional Polar Response



Cardioid Polar Response

Supercardioid Polar Response
Types of Microphones
Carbon Microphones
analog telephones, headsets
diaphragm compresses carbon granules
durable, cheap to make
limited frequency range
o directional properties
uses piezoelectric crystals
used with portable tape recorders

corrugated strip of metal foil between magnetic poles
not too expensive

diaphragm as electrode located near a second electrode
vibration in diaphragm causes variation in condenser
high quality
very expensive
requires gentle handling - studio use primarily

most common theatre mike
coil in magnetic field
directional or omni-directional
high quality
reasonably priced

MPAC Microphone Options

Shure SM 58
dynamic cardioid
upper range peak - good for voices
built-in windscreen
very durable

Shure SM 57
dynamic cardioid
contoured frequency response
clear instrument recording
rich vocal pickup

built-in windscreen
very durable

Shure BETA 87A
condenser supercardioid
smooth feqquncy response
built-in windscreen

EV 658 (unmarked)
dynamic cardioid
short polar response envelope
good for micing in front of loudspeakers

RE 10/ RE 15
dynamic cardioid
flatter frequency response
good for micing instruments
serve well as audio monitors

omni-diretional dynamic
flat frequency response

condenser cardioid
profesional studio applications
exceptional detail, low noise

condenser hypercardioid
narrow reception angle
long distance pickup
phantom power required

pressure zone microphone
phase coherent cardioid
condenser diaphragm located 3/1,000th of an inch from pressure plate
smooth polar response
low profile

Shure U1-UA Wireless
Countryman B3 dynamic omni-directional lavelier microphone
light skin colored mic cable
UHF signal from belt pack - 10 possible channels
antenna should not be coiled or shortened
2 AA 1.5 volt batteries, onboard meter, good for 5 hours
power switch