Introduction to Wireless Microphone Systems

Introduction to Wireless Microphone Systems
INTRODUCTION TO
WIRELESS
MICROPHONE
SYSTEMS
A Shure Educational Publication
INTRODUCTION TO WIRELESS
MICROPHONE SYSTEMS
Table of Contents
Product Glossary......................................................... 4
Discover the components of a wireless system.
Concept Guide............................................................ 7
Understand the unique electronics that make wireless systems
work and the features that help determine the right wireless
options for you.
Needs Analysis.......................................................... 11
A series of questions to assess wireless application
possibilities and benefits for your performance situation.
Considerations.......................................................... 15
Signal path, receiver and antennae placement and battery
information.
NO CABLES. NO WORRIES.
Conventional wired microphones convert sound into an
electrical audio signal that is sent to the sound system
through a cable. Live music stages that are crowded with
cables from microphones for vocals, guitars, drums and
other instruments can become a snake pit of overlapping
wires.
Wireless microphones convert audio signals created
by microphones into radio signals, which are sent by a
transmitter through the air to a receiver. The receiver
converts the radio signals back into audio signals which
are then sent through the sound system. They eliminate
the need for cables, so you’re no longer tethered to a
sound system or tripping through messy performing
environments.
With continuous technological advances and
improvements in sound quality and reliability, wireless
microphones are more affordable and popular than ever.
Wireless Microphone Systems
Their potential uses go far beyond the stage. You can find
wireless microphones in exercise studios, schools, houses
of worship, presentation halls – anywhere a performer or
presenter wants true freedom of movement.
SIMPLICITY
Set up and go for it. Your stage is cleaner and your
mics are less intrusive, so you can concentrate on your
performance.
MOBILITY
Be even more expressive. Wireless microphones cut you
loose wherever you perform.
VERSATILITY
Multiple microphone choices, system configurations
and features mean wireless systems can adapt to nearly
anything you do and any place you go.
PRODUCT GLOSSARY
Wireless Microphone Systems range from simple to sophisticated. But they all include various combinations of
these key components:
• Transmitters: Convert the audio signal from the microphone to a radio signal. There are two types:
Handheld Microphone Transmitter – Combines handheld microphone element and transmitter in one unit.
Bodypack Transmitter – Wearable unit with a connector that accepts microphones or guitar cables.
• Microphones (for Bodypack Transmitters): Headworn, lavalier and instrument microphones ideal for a variety of vocal
and instrument applications
• Receivers: Modules that receive radio signals sent from transmitters and convert them back to audio.
1
TRANSMITTING
Two types of transmitters-handheld or bodypack – convert audio signals to radio signals
so they can be sent, without a cable, to a wireless receiver at the mixing console.
Headworn Vocal Mic
Handheld Microphone Transmitter
This microphone/transmitter integrates the transmitter
into the microphone handle, so both functions are
contained in one unit.
Like conventional wired microphones, wireless
handheld vocal microphones are tailored to meet
diverse performance vocal requirements and musician
preferences. Many different choices are available.
Rugged, comfortable, easy-to-position headsets provide
superior voice pickup in any active user setting.
Lavalier Vocal Mic
A range of sizes combine low visibility with high-quality
professional audio. They provide full, clear sound for
speech applications.
Clip-On Instrument Mic
Bodypack Transmitter
Lavalier, Headworn and Instrument Microphones,
as well as guitar cables, must plug into a Bodypack
Transmitter to send their audio signals. Sleek,
lightweight bodypacks can be easily clipped to clothing
or a guitar strap.
A versatile solution for high volume wind, brass and
percussion players. Gooseneck and clamp ensure
secure fit and positioning.
2
RECEIVING
Wireless receivers convert RF signals sent from a Handheld Microphone Transmitter or a Bodypack
Transmittter back to an audio signal. They come in these receiver configurations:
Single Channel Receivers
Multi-Channel Receivers
This is the most common type of receiver. Receivers
usually have XLR and ¼” audio outputs for connection
to a variety of devices. Units may be free standing or
rack-mountable and are typically AC-powered. Indicators
for power and signal levels may be present. Diversity
receivers utilize two antennas, which may be removable
or permanently attached.
This type provides two or more channels of wireless,
allowing multiple users to be wireless. These systems
generally come with various transmitter combinations.
Common options are dual or quad receivers.
Portable Receivers
Guitar Pedal Receiver
These resemble portable transmitters externally; they
are characterized by small size; one or two outputs;
minimal controls and indicators, and are typically battery
powered. Portable receivers are great for mounting
directly to a camcorder or DSLR camera.
This receiver type is designed with the guitarist or bass
player in mind. It mounts on a pedal board, and can be
powered by the pedal board itself.
Guitar/Bass Cable
Connects any guitar to a Bodypack for wireless
performance.
Wireless Microphone Systems
5
SETUP: VOCALS
This wireless system setup example follows the wireless signal path for
common vocal system configurations using a handheld microphone.
Singer
Application:
Profile | Handheld
A handheld wireless
setup is great for
performers who want
a handheld vocal
microphone that’s not
connected to a
bodypack transmitter.
Ideal for:
Vocalists
Speakers / Presenters
DJs
CONCEPT GUIDE
These technical and operating concepts help define how a wireless microphone system functions and which is best
suited to a specific application.
Analog or Digital
Analog systems utilize proven radio technology that
offers quality audio performance and high channel
count, even with entry-level systems. Digital systems
feature exceptionally clear audio, but potentially fewer
on-air channels. High-end digital systems, however, offer
the best of both worlds, combining superb audio with
the ability to use many wireless systems in crowded RF
environments.
Frequency Ranges
Every wireless microphone system transmits and
receives audio on a specific radio frequency, known as
the operating frequency. These frequencies are typically
divided into these bands, or ranges.
The UHF-TV Band – Unused television channels in this
range are available for wireless microphones and other
wireless audio devices. Most cities have a significant
number of television stations and the largest cities
may also have public safety operations, but there are
sufficient unused television channels available for most
wireless users to find a clear channel. However, this
spectrum is becoming increasingly crowded. Users
may be licensed or unlicensed in the UHF Band.
Multiple frequency range options are available throughout
the UHF band, and the best one to use will vary from city
to city. In order to determine the best range for your area,
you may want to consult with the manufacturer.
The 900 MHz Range – This band (specifically, 902 –
928 MHz) offers additional channels outside of the TV
channel range. Users are allowed to operate without
a license in this range. There are several high quality
wireless microphone systems that operate in this range,
most of them fully digital. While 900 MHz wireless
microphone systems are legal to use in the United States
(and most of the Americas), they are not necessarily legal
to use in all parts of the world. Check with your local
regulatory agency if you are unsure.
The 2.4 GHz Band has attracted some interest for
wireless microphone use. Advantages of this band
are: worldwide, license-free operation, and very short
antennas, but there is some potential from interference
from Wi-Fi devices. This band is great for users who only
need a few channels of wireless, but for applications
with many channels of wireless, the UHF-TV band may
be preferred.
Frequency Selection
Fixed Frequency – Fixed-frequency systems are pre-set
to their operating frequency and cannot be changed by
the user. They are suitable for use in one particular area
or installation, but due to their limited capabilities are
not commonly available anymore.
Frequency Agile – Frequency-agile (tunable) systems
allow users to quickly change frequencies to avoid local
TV channels, other wireless users, or other interference
sources. Most modern wireless microphone systems
offer some degree of frequency agility.
Tips! Many newer wireless systems include easy to
use features, such as Scan and Sync which quickly
and easily sets up the system with a clear channel.
Some wireless manufacturers have online tools and
resources such as wireless frequency finders to help
users find the best frequency for their location.
Using Multiple Wireless Microphones
Each microphone needs its own frequency to operate
and transmit properly. So it is not possible to use two
wireless systems on the same frequency in the same
venue or to use two wireless microphones with just one
receiver (unless you are using a dual-channel receiver).
The individual frequency used by each microphone
requires a certain amount of space within a particular
frequency band. When two wireless systems are used
together, the frequencies must be separated by some
minimum amount that depends on the design of the
system. If frequencies are set too close, microphones
will compete with each other, and each system will
experience noisy interference and/or sound dropouts.
As more transmitters and receivers are added to a
particular setup, interaction between frequencies
increases. This interaction produces more interfering
frequencies that need to be avoided. More advanced
wireless systems offer greater frequency selection,
flexibility and the ability to combine more receivers
and transmitters to serve more users. Many of these
systems offer pre-configured groups of compatible
frequencies to accommodate multiple users, as well
as software that can scan for the clearest frequencies
in any one particular location.
Visit the Shure Wireless Frequency Finder for the most up to date
frequencies for Shure Wireless System use in the United States.
http://www.shure.com/americas/support/tools/wireless-frequency-finder
Wireless Microphone Systems
7
SETUP: PRESENTER
Application:
Profile | Lavalier
A lavalier microphone
and bodypack transmitter
setup can work for any
presenter or performer.
This wireless system setup example follows the wireless signal path
for common vocal system configurations using a lavalier microphone.
CONCEPT GUIDE
Pol
ar Pattern / Directionality
Microphone Basics
There’s more to a microphone than its shape. While invisible from the outside of a microphone, these two fundamental
operating principles can help fine tune the selection of the right microphone for your wireless system application.
Application:
Profile | Headworn
Pol
ar Pattern / Directionality
For situations where
Operating Principles
performers or presenters
Polar Pattern
How a microphone changes sound into an electrical
work with louder sound
A polar pattern is the graphic representation of a
signal. This is determined by the type of Transducer
systems or use stage
microphone’s directional sensitivity, which is how a
inside the microphone. The two most common types are:
monitor speakers, a
microphone picks up sound from different directions.
headworn microphone is
These are the three most common polar patterns:
a more effective choice.
Presenter
Ideal for:
Speakers / Presenters
Worship Leaders
Theater Stage Actors
DYNAMIC
These are workhorse microphone elements with great
sound that stand up to rugged regular use. They are also
generally more affordable options.
CONDENSER
These produce a crisper, more defined sound and are
better at capturing subtle details of delicate voices and
instruments. They also require power to operate, which is
supplied by the battery in a handheld wireless transmitter.
Lavalier
CARDIOID
These patterns pick up the most sound from in front of
the microphone and some from the sides They are less
susceptible to feedback in loud environments.
SUPERCARDIOID
These are tighter patterns that help screen unwanted
sound sources. They are perfect for individual instruments
in a multi-instrument setting or single sources in noisy
environments. They also provide the best rejection of
feedback when used with floor wedge monitor speakers.
OMNIDIRECTIONAL
Omnidirectional polar patterns are equally sensitive to
sound from all directions. These are most often found in
lavalier microphones.
Signal
transmitted
to Receiver
Wireless Receiver
Bodypack
Transmitter
Wireless Microphone Systems
9
SETUP: GUITAR
This wireless system setup example follows the wireless
signal path for common instrument system configurations.
Application:
Profile | Guitar
A wireless guitar setup
helps guitarists move
freely anywhere
onstage.
Ideal for:
Electric Guitarists
Acoustic Guitarists
Bass Guitarists
Guitarist
NEEDS ANALYSIS
Microphone Configurations
Wireless system microphone and transmitter choices afford presenters and performers great flexibility in matching an
application to a wireless configuration.
1
What type of microphone / transmitter
configuration best fits your performance needs?
Application
Configuration
Vocalist
Handheld Microphone /
Transmitter
Singing Dancer
Singing Keyboardist
Singing Drummer
Fitness Instructor
Dance Instructor
Headworn Mic +
Bodypack Transmitter
2
Would your performance benefit from a
particular microphone design profile?
Your usage application is only one key factor in
choosing a wireless microphone. Also consider the
microphone transducer design and polar pattern.
These greatly impact how any wireless microphone
reproduces your live sound.
For example, if you are a vocalist who performs onstage with loud monitors, you might want a handheld
transmitter with a tight supercardioid polar pattern to
minimize feedback.
If you tend to sing softly, a condenser microphone will
more smoothly capture the subtleties and details of
your voice.
Presenter
Worship Leader
Stage Actors
Lavalier Mic +
Bodypack Transmitter
OR
Bodypack
Transmitter
Headworn Mic +
Bodypack Transmitter
Horn | Percussion
Clip-On Mic +
Bodypack Transmitter
Guitar | Bass
Signal
transmitted
to Receiver
Instrument Cable +
Bodypack Transmitter
Guitar Cable links
to Bodypack
Guitar Pedal Receiver
Wireless Microphone Systems
11
SETUP: INSTRUMENT
Application:
Profile | Clip-On
A small, clip-on
instrument
microphone and
Bodypack Transmitter
is a great wireless
solution for many
acoustic instruments.
This wireless system setup example follows the wireless
signal path for common instrument system configurations.
Ideal for:
Brass
Woodwind
Percussion
Saxaphone
Bodypack
Transmitter
Clip-On
Instrument
Mic
NEEDS ANALYSIS
System Configurations
Different transmitter and receiver options in every wireless system are also designed to respond to the special needs of
different user applications.
3
Where do you intend to use your wireless
system? One location? Many locations?
4
How many wireless systems will be in use at
the time and location?
ONE LOCATION
If you intend to use the wireless system in one location,
you simply need to make sure that you select a system
that operates on frequencies compatible with your
location’s available UHF broadcast TV channels, or
operate on unlicensed frequencies.
ONE SYSTEM
If you are operating a single wireless system in a
location where there are no other wireless systems in
use, you will not have any special multisystem needs to
manage.
MULTIPLE LOCATIONS
If you intend to use the wireless system in different
cities, you will probably encounter different active TV
channels. A frequency-agile wireless system lets you
change frequencies to adapt to changing situations
as you travel. Choose a system with Scan and Sync
features, which will quickly and easily set up the
system on a clear channel.
MULTIPLE SYSTEMS
If you operate more than one wireless system and move
from venue to venue, it is usually more convenient to
mount receivers in a small rack case. Some wireless
systems allow two receivers to mount together in one
rack space. These can be used with an antenna splitter
that feeds one “master” pair of antennas to serve all
receivers.
INTERNATIONAL LOCATIONS
The 2.4 GHz Band can be used internationally with no
license requirement.
There is a limit to the number of wireless systems
that can be used in one location. Each system must
transmit on its own frequency. And those frequencies
must be selected carefully to prevent interference.
Better wireless systems allow for more units to be
operated at the same time without interference.
Consult with the manufacturer for advice on ensuring
multisystem operation.
Signal
transmitted
to Receiver
Wireless Receiver
Wireless Microphone Systems
13
SETUP: HEADWORN
Application:
Profile | Headworn
For situations where
performers or presenters
work with louder sound
systems or use stage
monitor speakers, a
headworn microphone is
a more effective choice.
This wireless system setup example follows the wireless signal path
for common vocal system configurations using a headworn microphone.
Ideal for:
Fitness / Dance
Instructors
Singing Dancers or
Instrumentalists (such
as drummers and
keyboardists)
Instructor
CONSIDERATIONS
RF SIGNALS
POWER
Signal path from transmitter to receiver
Batteries
The signal path and signal strength between transmitter
and receiver is affected not only by distance, but also
by obstructions. Each installation location presents its
own challenges.
Unlike most wired microphones, all wireless mic
transmitters require batteries. As a result, batteries are
an important and constant replacement part. If you
are using non-rechargeable batteries, alkaline batteries
offer the longest life for wireless applications. Off the
shelf rechargeable batteries, such as nickel-cadmium
or nickel-metal hydride, though an economical choice,
typically last less than three hours before recharging is
necessary. This short runtime makes them undesirable
for most performers.
Maintain line-of-sight between the transmitter and
receiver antennas as much as possible. Avoid metal
objects, walls, and large numbers of people between
the receiving antenna and its associated transmitter.
Ideally, this means that receiving antennas should be in
the same room as the transmitters and elevated above
the audience or other obstructions.
Headworn
Mic
Some manufacturers offer proprietary rechargeable
batteries that utilize more advanced technology, such
as lithium-ion, that will provide continuous usage that
often surpasses that of alkaline batteries.
Receiver and antenna placement
PLACE THE RECEIVER PROPERLY
Receivers are subject to interference from external
sources that emit radio frequencies. Where possible,
keep receivers a few feet (or rack spaces) away from CD
players, cell phones, digital special-effects units, and
lighting boards, and other such devices.
POSITION ANTENNAS PROPERLY
Ideally, antennas should be positioned above an
audience or other obstructions so that the transmitter
and receiver can “see” one another. When receivers are
mounted in a rack, antennas must be located on the
front panel or allowed to project through the top of the
rack. Antennas should be oriented vertically or angled
apart to maximize the distance between antenna tips.
Signal
transmitted
to Receiver
Bodypack
Transmitter
Wireless Receiver
Wireless Microphone Systems
15
LEARN MORE
Wireless Microphone Systems: Selection & Operation Guide
This booklet provides greater technical detail about specific wireless microphone systems,
components, frequency selection, usage applications, setup suggestions and system expansion.
You can download a PDF of this guide at:
http://www.shure.com/americas/support/downloads/publications
Additional Shure educational publications available:
Audio Systems Guide for Houses of Worship
Audio Systems Guide for Video Production
Personal Monitor Systems | Introduction Guide
Mic Techniques for Music–Sound Reinforcement
Mic Techniques for Music–Recording
Introduction: Home Recording and Podcasting
United States, Canada,
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Shure Incorporated
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Niles, IL 60714-4608 USA
Phone: +1 847-600-2000
Fax: +1 847-600-1212 (USA)
Fax: +1 847-600-6446
Email: [email protected]
www.shure.com
www.shure.com
©2014 Shure Incorporated
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Fax: +49-7262-9249114
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AL27274
11/2014
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