AUDIO GUIDE BOOK
A Quick Guide to Basic Audio Gear : MNP
LEADS
USE THIS PAGE FOR NOTES
XLR
➤
These connectors are
frequently used in
professional applications.
➤
They are generally used with
PA systems for microphones,
power amplifiers, powered
speakers, etc.
SPEAKON CONNECTORS
➤
Speakons have the exact same
function as trs and xlr's
➤
It is a balanced signal cable
➤
It is used to connect power
amplifiers and passive
speakers. After inserting the
cable, turn it clockwise to lock
it.
TRS CABLES
➤
There are two types of phone
connector: stereo and
monaural.
➤
They are used to handle stereo
signals for headphones, as
well as to insert effects.
OTHER CABLES
➤
RCA Pin- These connectors are
generally used with audio and
audio-visual (AV) equipment. The
white connector is used for sending
signals to the left (L) channel, and
the red connector is used for
sending signals to the right (R)
channel.
➤
USB connectors are used to send
and receive audio signals to and
from mixers with audio interface
functionality and personal
computers. These connectors are
used to record live performance
mixes on a personal computer, or
for music production.
TYPES OF MICROPHONES
USE THIS PAGE FOR NOTES
TYPES OF MICROPHONES
➤
Dynamic microphones are just ordinary
microphones that use diaphragms, magnets, and
coils.
➤
Dynamic microphones Characteristics
Construction is simple and comparatively sturdy.
No power supply is required.
Relatively inexpensive.
➤
Condenser microphones work a slightly different
way by using a diaphragm to move the metal
plates of a capacitor (an electric-charge storing
device) and generate a current that way.
➤
Condenser microphonesCharacteristics
Good sensitivity at all frequencies.
Power supply is required.
Vulnerable to structural vibration and humidity. ➤
All microphones come under theses two
categories
POLAR PATTERNS
USE THIS PAGE FOR NOTES
POLAR PATTERNS OF MICS
➤
A Polar Pattern is the
direction that certain
microphones pick up sound.
➤
These graphs visually
represent the microphones
sensitivity to sound relative to
the direction or angle from
which the sound arrives.
➤
The most common types of
directionality, plotted as polar
patterns are: Omnidirectional,
Cardioid and Supercardioid.
When to Use Cardioids
The advantage of using cardioid mics seems obvious, right? It records where you point it, and
ignores everything else.
But here are some specific examples of when it’s ESPECIALLY useful:
• Miking up a drum kit – With so many instruments so close together, isolation might seem
impossible. But it CAN be done, with the right cardioid mics, positioned in the right spots.
• Live performances – On-stage, when sounds are coming at you from all directions,
cardioid mics are great maintaining isolation and preventing feedback.
• Untreated rooms – In rooms with poor acoustics, close-miking with cardioid mics can
work wonders at minimizing reflected sound.
When to Use Omni’s
Here are common situations when they’re preferable:
• When recording the sound of the room – such as with room mics for drums.
• When recording a wide sound source – such as an orchestra, choir, or grand piano.
• When recording a moving target – such as an acoustic guitar player who can’t sit still.
• When recording in stereo – such as with the common A/B technique.
It’s common to use figure-8 mics for one of the following 3 reasons:
1 for stereo recording
2 with ribbon mics
3 for maximum isolation of off-axis sounds
SPEAKERS
USE THIS PAGE FOR NOTES
PASSIVE SPEAKERS
➤
These speakers require a
separate power amplifier in
order to produce sound.
➤
Pros are: they're lighter and
much cheaper without
sacrificing sound quality
➤
Cons are: you need a separate
amplifier to provide power
POWERED SPEAKERS
➤
Speakers that contain an internal
power amplifier can also be called
"active speakers".
➤
Since these speakers contain a builtin power amplifier, they can be
directly connected to a mixer, which
reduces the number of cables
required. (Though of course an
electricity power cable needs to be
connected to each powered speaker).
➤
Pros: less equipment to transport,
amplifier is designed specifically to
drive that speaker.
➤
Cons: heavier than a passive speaker
with the same design, also much
more expensive
Main speakers
These are the speakers that deliver most of the
sound to the audience or listeners. Decide on the
size and number of speakers according to the size of
the venue, as well as by the amplifier output power
(in the case of passive speakers).
Subwoofers
These speakers are designed specifically for low
frequency sound playback, and are used together
with the main speakers to boost the low-end sound
range.
Monitor speakers
These speakers are used by the performers to
monitor the sound. Monitor speakers are positioned
in various ways depending on their shape, such as
on the floor or on a stand.
MIXERS/DESKS
USE THIS PAGE FOR NOTES
TYPES OF MIXERS
Analog mixers
Analog mixers adjust the volume and tone of input audio signals.
Most of the control knobs and faders are arranged on the top panel,
so it is easy to understand the signal flow and what state the audio
is in. Operating analog mixers is normally an intuitive process.
Digital mixers
Digital mixers process input audio signals and adjust their volume
and tone using digital signal processing technology. Various kinds
of tone control that would be impossible using analog equipment
can be applied using digital processing. Digital mixers can store the
positions of faders and knobs, and recall these positions in an
instant. The faders and knobs perform various functions, so the unit
itself remains compact, even if the number of channels increases.
Generally a digital mixer will require more experience to set up
effectively, but will offer far greater functionality than an analog
mixer.
Powered mixers
Powered mixers are analog mixers with built-in power amplifiers.
For this reason, sound can be played with the mixer directly
connected to speakers. In cases where the same equipment is
always connected, powered mixers can be used by simply turning
the power on, so operation is simplified and convenient.
Microphone input channel
Audio signals picked up by a microphone are very weak,
so they must be amplified by using the head amplifier
(GAIN) of the mixer. Connect to the MIC connector.
Note: Phantom power (often labelled as "+48V") is
required when using a condenser microphone.
Line input channel
Line level devices such as keyboards and CD players are
connected to the LINE connector.
When both MIC and LINE inputs are available on same
channel, use the LINE connector. When the same
connector is used for both MIC and LINE, reduce the
level by pushing the PAD button so that audio is not
distorted (Remember line signals have a higher level
than mic signals).
INPUT CHANNELS
(FOCUSING ON ANALOG)
➤
The number of input channels in a mixer
is extremely important, as this indicates
the number of microphone and musical
instrument signals that can be handled.
➤
In addition to the number of input
channels in a mixer, it is also important
to consider such factors as how many of
those input channels are for
microphones, whether line input
channels are monaural only, and whether
inputs will accept stereo signals.
➤
For example, when using a mixer with a
band, at least eight channels for input
may be required for microphones to pick
up the sound of the whole drum kit. In
this case, a model that is equipped with
enough channels that are compatible
with microphones should be chosen.
EQUALISERS
Mixers are equipped with equalizers that adjust the tone of each channel. Some equalizers have just 2-bands, which can
adjust lows and highs. Some are 3-band equalizers, which modify the sound by boosting and cutting lows, mids, and highs.
MIXER FUNCTIONS
➤
High Pass Filter
➤
The HPF cuts unnecessary low
frequencies at the input. Most
microphone and mic/line inputs
have an HPF function, but some
dedicated line inputs may not.
HPFs are often used for hi-hat,
snare, and vocals to cut
unnecessary low frequencies
and therefore create a cleaner
sound. They are also used to
eliminate unwanted popping
noises when picking up voices,
such as during speeches.
MIXER FUNCTIONS
➤
Panning
➤
This adjusts the sound playing
from left and right speakers.
➤
Example: You can have Vocals
coming from just the right or
left.
➤
It is used to widen the sound
image, or to position each
input relative to their location
on the stage.
MIXER FUNCTIONS
Faders should be set at zero and adjusted according to the sound. Many desk’s have a metering light system
you want to stay within the green lights, RED is ‘too hot’ which is way to loud.
➤
Level Faders/knobs
➤
These adjust the volume of
each channel, group, stereo
output, etc. Fader-type
controls allow for quick
operation. Though some
mixers use knob-type volume
controllers.
SIMPLE DO’S AND DON’T’S
DO
DON’T
Keep your LEADS neat and tidy - use GAFFA Tape
on trailing leads to avoid trips and wires being
pulled out of the sockets.
Have glasses full of liquid on stage or placed on
speakers/amps or equipment - Drink from a
screwtop or resealable bottle (less likely to tip &
ruin your electrical equipment & cause electrocution
or severe equipment damage!).
ALWAYS use an extension lead or plug with a safety
cut off feature. Extension leads should always be
fully extended and checked for breaks or kinks in the
wire before use.
Plug anything but Speaker Leads into the Speaker
Outputs!
Clean your leads regularly with a soft (slightly)
damp cloth & check for wear & tear.
Use leads or plugs that are split or broken.
Perform regular maintenance checks on all
equipment, cables, leads, plugs and accessories.
Block emergancy exits with equipment
Carry spare fuses/batteries/strings/plugs/
screwdriver/pen/paper & a torch!
Have loose trailing leads that people can trip over!