YAMAHA Understanding Basic Audio Owner’s Manual
- August 9, 2024
- Yamaha
Table of Contents
UNDERSTANDING
BASIC AUDIO
Understanding Basic Audio
THE MOST BASIC SOUND SYSTEM IS A MIC PLUGGED INTO A SPEAKER. From there, it
gets more complicated. You need to understand the flow of sound and how your
gear enables you to adjust that flow in different ways. Don’t worry; you’re in
the right place. This guide was designed to get you up and running.
SIGNAL FLOW
The most important skill a live sound engineer must have is a solid
understanding of signal flow; you must know where the signal — and by that, I
mean the source of sound — is coming from, where it needs to go and how to get
it there. To do that, you need to understand how all the pieces of the sound
system work together.
MIXING CONSOLE
The console is command central, where you receive inputs (instruments, mics,
etc.), process and combine their “content,” and then route the results to the
proper outputs. Every console is different, but they all serve the same
function.
Each input goes into a channel on the mixer. One channel may be a lead singer,
another might be a synthesizer, another could be backup vocals, etc. You then
change the channels’ signals with processors. Consoles often include semi-
parametric three-band EQ on every channel. Several also include effects (FX),
as well. Others are available through outboard processors, such as gates,
compressors, and dedicated FX units. An AUX (for auxiliary) output is usually
for sending a signal to those outboard processors. There are added outputs for
stage and in-ear monitors (IEMs).
After signal processing, all channels are eventually routed to the main stereo
outputs and sent to the sound system (amps, speakers) for the audience to
hear.
First, though, you need to connect the console to the speakers.
GRAPHIC EQUALIZERS
Console Main Outputs → GEQs 
Graphic equalizers (GEQs) are
used to correct the frequency response of a speaker. Connect the main outputs
of your console to the GEQ and use it to “tune the room” or correct problem
frequencies caused by standing waves in the room (reflections).
When using stage monitors, connect each AUX output to a GEQ channel before
sending the signal to the stage. This enables you to “ring out” the monitors
or cut frequencies likely to cause feedback.
CROSSOVERS (FOR PASSIVE SPEAKERS)
Console Main Outputs → GEQs → Crossover
Crossovers are devices that split your audio signal in two — low frequencies
go to subwoofers, and everything else goes to the main speakers. Plug the main
outputs of your console into the GEQ, then plug the outputs of the GEQ into
the inputs of the crossover. Set the frequency where you’d like to split the
signals, then connect the “low” outputs to the power amps for the subs and the
“high” outputs to the power amps for the main speakers.
Some crossovers include three-way splitting for low, mid and high speakers,
typically found on more advanced systems. Active (powered) speakers have
built-in crossovers, so there’s no need for an outboard unit.
POWER AMPLIFIERS (FOR PASSIVE SPEAKERS)
Console Main Outputs → GEQs → Crossover → Power Amps 
Power amps have one job: supply power to passive speakers.
There’s nothing fancy about them. Their only control is volume output. Some
engineers choose to run their power amps at full blast, although if not
correctly gain staged, this could lead to a low signal-to-noise ratio. Power
amps are vital to your sound system. If you use the wrong amp, the speakers
could blow, the amp could catch fire, or both! To properly pair speakers and
power amps, you need to know the following:
- Amp impedance
- Amp power
- Speaker impedance
- Speaker power
Ohms measure resistance (impedance) and tell us how resistant the power amps
and speakers are to electricity. Always ensure the speakers and power amps
have the same ohm rating (8 ohm, 4 ohm, 2 ohm) running parallel or in series.
Power is measured in watts and sometimes referred to as program, continuous or
root-mean-square (RMS) power rating. This is the continuous music power that
the amp can deliver. You must use an amp that is 50% more powerful than your
speakers. For instance, if you’re using two 8-ohm, 1,000-watt speakers, you’ll
need two 8-ohm, 1500-watt power amps or a single 8-ohm, 2-channel, 3,000-watt
power amp.
After connecting your crossover outputs to the power amps, finish the chain by
connecting the power amps to the speakers. Active speakers have built-in amps,
so there’s no need for outboard amp units.
MAIN SPEAKERS
Console Main Outputs → GEQs → Crossover → Power Amps → Main Speakers
Speakers are the end of your signal chain — the last stop
before all this electricity turns back into music. Speakers come in two basic
types: active and passive.
Active speakers are powered — there’s an amp built in. All you need to do is
plug the power cable into the wall to turn them on. These are available from
small to large speakers. To connect active speakers to your console, run an
XLR or tip- ring-sleeve (TRS) signal cable from the main outputs of the GEQ to
the inputs on the speakers.
Passive speakers are unpowered. They require a connection to an external power
amp to turn on. These are very common in permanent installations. To connect
passive speakers to your console, run an XLR signal cable from the main
outputs of the GEQ to the inputs on your crossovers and then to the amps. Now
connect the power amps’ outputs to the speakers’ inputs using 1/4-inch tip-
sleeve (TS) or Speakon® cables. SUBWOOFERS
Console Main Outputs → GEQs → Crossover → Power Amps → Subwoofers Systems can
include multiple subwoofers for extra low-end reinforcement. If you use two or
fewer active subwoofers, simply route the console’s main outputs to the
subwoofers’ inputs, then use the “thru” outputs to connect the subwoofers to
the active “tops” — or main speakers — using XLRs.
Active subwoofers include built-in crossovers — devices that split your signal
in two. If you’re using passive speakers, you need an outboard crossover.
You’ll need a speaker management system if you use more than two subwoofers.
These usually include many digital signal processors (DSP), such as EQ,
compressors, limiters and stereo imagers. Most importantly, they allow you to
split a stereo signal into eight or more outputs, which gives you the freedom
to include multiple subs.
MONITORS
Console Main Outputs → GEQs → Power Amps → Monitors
Now that you have the sound system up and running, it’s time to connect the
stage monitors so the band can hear itself. Stage monitors are connected
essentially in the same way as the main speakers, but they use the AUX outputs
instead of the main outputs. Each stage monitor needs its own GEQ and AUX
send. Start at the console and connect the AUX outputs to the GEQs using XLR
or TRS cables.
Then, the GEQs are connected to the amps using the same type of cables.
Finally, connect the power amps to the monitors using TS or Speakon cables.
Active stage monitors have built-in power amps, so there’s no need for
outboard amps.
For IEMs, use a system where you connect the AUX output to the input on the
IEM mixer. Each musician can then adjust their mix using the compatible
controller. 
TURNING THE SYSTEM ON
Now that everything’s connected, you just need to turn it all on. Always start
at the beginning of the signal chain — the console. Then, simply follow the
chain down the line. Boot up the GEQs next, followed by the crossover and any
added processing. The last things to turn on are the power amps/speakers; if
you turn them on earlier, you’ll hear a nasty pop. CHANNEL STRIPS
Mixing consoles can be intimidating, have a ton of channels, dozens of knobs,
buttons and touch screens, and more LED lights than an average Christmas tree.
The main takeaway is that if you understand how one channel strip works, you
can understand how roughly 80% of the console works.
Aside from the center — or “master” — section, the rest of the console works
the same as channel one. If you’re accustomed to mixing in a digital audio
workstation (DAW), you’ll be pleased to see that the channel strips are laid
out almost the same way on the console, and while every console is a little
different, they all work in essentially the same way.
PREAMP / GAIN
It all starts with the input preamp. Whether you’re plugging mics directly
into the back of the board or using a “stage snake” to feed the signals from
the stage, the first step is amplifying the mic using the gain knob on the
console.
While we’re on the subject, what exactly is gain? First of all, let’s talk
about what gain isn’t. Gain is not volume. To increase the signal volume, you
reach for the channel fader, not the gain knob. Gain, on the other hand,
controls mic or channel sensitivity. It increases the intensity of what the
microphone can “hear” and is used to dial in the proper intensity of each mic
or instrument. Too much gain can cause the signal to clip and distort. There
is too little gain, and the signal feels weak and noisy.
To set the gain for a channel, have a musician play their instrument, and,
with the channel fader down, slowly turn up the gain knob until you hit the
console’s “sweet spot.” Every console is different, but this is usually where
signal lights turn from green to yellow or orange. Just make sure you keep it
out of the red!
After setting the gain levels, slowly bring up the channel fader until the
instrument is at the proper volume in the main speakers for the room.
INSERTS
From here, the signal typically travels through the “insert” section, where
youcan connect outboard processors (like gates and compressors) before
runningthrough the EQ section. Most consoles have a pre/post button that
allows you to move the insert point before or after the EQ. 
On most
large-format consoles, channels have a 1/4-inch “insert send” output to send
the signal to the processor and a 1/4-inch “insert return” input to receive
the processed signal. Some compact consoles use a single 1/4-inch Y-cable
insert point, which has three ends: one that plugs into the insert point on
the back of the console, one that plugs into the input of the processor and
one that plugs into the output of the processor.
EQ
Up next is the EQ section. Most consoles are outfitted with semi-parametric
EQ, which sounds intimidating but really shouldn’t. You’ll typically have
fixed low and high bands with adjustable gain and frequencies. Occasionally,
there will be a button to switch between a bell and a shelf shape. 
Next, you’ll
have bell-shaped low-mid and high-mid bands with fully adjustable gain,
frequency and Q (bandwidth) parameters.
Finally, a fixed high-pass filter switch is usually set to a specific slope
and frequency (usually around 80 Hz). This is mainly used for vocal mics.
AUX SENDS
Next, your signal runs through the AUX sendsection. Most consoles have four
or more AUXsends, which can duplicate signals and route them to one of two
places: monitors or FX processors (like reverb or delay).
To send a signal to an AUX send, simply find the AUX send section of the
desired channel and turn up the send to the corresponding AUX channel. Ensure
the AUX Outputs on the back of the mixing console are connected to the correct
monitors and/or FX processors.
Remember, when using outboard FX processors, you can send a signal from the
AUX sends, but if you want to hear the effect, you need to return it as well.
Most consoles have dedicated Stereo AUX returns specifically for FX, although
any channel input will do.
There’s also an AUX Master section on the console, which has a Master volume
control for each AUX send just in case you have the balance right but need a
little more or less volume overall. Make sure it’s turned up (typically to
unity), or you won’t be sending any signal.
PAN KNOB, FADER AND ROUTING BUTTONS
Next are the pan pot, volume fader and routing assignment buttons.
Aside from panning stereo signals left and right, there’s no real need for
panning live sound. Sure, some engineers choose to tilt their toms a little
this way or move a keyboard over there to get it out of the way in a busy mix,
but overall, most signals are panned in the center. Panning makes sense when
everyone is wearing headphones, but when everyone in the room has a different
place in the stereo spectrum, it starts to cause more problems than it’s
worth.
The next piece of the channel strip is the fader. Get to know how the fader
feels under your fingers. Become one with the fader.
From there, you need to tell the signal where to go. Most consoles usually
have buttons (M, 1+2, 3+4, etc.) next to each fader, allowing you to send the
signal to the mains and/or one or more subgroups.
Often, engineers use channel strips to process individual signals and
subgroups to balance the mix, which is easier than pulling up eight mics
simultaneously during the drum solo. By routing similar signals to subgroups
(like drums, bass, guitars, vocals, etc.), you can balance levels by
controlling multiple mics simultaneously, leaving your other hand free to mix
FX, run lights or fight off droves of sound groupies. (We techs can always
dream, right?) 
BOARD MIX
While every engineer does things a little differently, below is an example of
a typical board mix, including common microphone options, inserts and AUX
sends. For demonstration purposes, we’ll assume you’re working with a four-
piece band: drums, bass, one guitar and keyboards, plus three vocalists. There
are three stage monitors: stage left, center stage and stage right. They’re
connected to AUX 1 through 3, respectively. You also have two FX processors:
one for reverb and one for delay. The reverb unit is connected to AUX
four.
This
template won’t work for every band, but using it as a starting point or a
reference guide when setting up should prepare you for most services.
Set your stage inputs to the console as you see them on stage, starting from
your left to your right.
GLOSSARY OF TERMS
Active Speakers: Powered speakers, also known as self-powered speakers, are
loudspeakers with built-in amplifiers. They can be connected directly to a
mixing console or other low-level audio signal sources without an external
amplifier. AUX: An AUX send is an output used on most live sound and recording
mixers. It allows you to create an “auxiliary” mix in which you have
individual-level control over each input channel on your mixer to your AUX
send output. This enables you to add effects to an output or channel on your
mixer.
Cue: This option on a mixer essentially allows a chosen track to be played in
your monitor headphones.
DAW: A digital audio workstation is an electronic device or application
software for recording, editing and producing audio files.
DI: Direct boxes are often referred to as DI — or “direct injection” — boxes.
Their primary purpose is to convert unbalanced and/or high-impedance
instrument signals into a format suitable for direct connection to a mixing
console’s mic input — without using a microphone.
Gain Stage: Gain staging is the process of managing the relative levels in
each step of an audio signal flow to prevent the introduction of noise and
distortion.
Graphic Equalizer (GEQ): This device is used to alter the frequency response
of an audio system using linear filters. Since equalizers adjust the amplitude
of audio signals at particular frequencies, they are, in other words,
frequency-specific volume knobs.
IEM: An in-ear monitor is used in place of monitor speakers, which are placed
on stage in front of band members.
Insert: In audio processing and sound reinforcement, an insert is an access
point built into the mixing console. It allows the audio engineer to add
external line- level devices — such as compressors or FX processors — into the
signal flow between the microphone preamplifier and the mix bus.
Passive Speakers: These loudspeakers do not have a built-in amplifier; they
must be connected to an amplifier through an ordinary speaker wire.
Pink Noise: A mixture of sound waves with an intensity that diminishes
proportionally with frequency, yielding approximately equal energy per octave.
Pre/Post: Pre and post sends are AUX sends; they control the sound sent to
objects like nursery room speakers, stage monitors or anything other than the
main house speakers. A pre-AUX send delivers the signal out of the mixer
BEFORE it passes through the channel fader (also known as pre-fader).
Preamp: A “preamplifier,” as the name suggests, prepares the signal from a
pickup or microphone for further amplification.
Q-Value: The “quality factor” defines the bandwidth of frequencies that will
be affected by an equalizer.
Semi-Parametric EQ: Sometimes called pseudo- or quasi-parametric EQ, this is a
parametric equalizer with one or more missing features. This term is sometimes
used to describe a single band of equalization, which generally means a
parametric EQ that does not have a Q control — the Q is fixed.
Signal-to-Noise Ratio (SNR): A measure that compares the desired signal level
to the background noise level. SNR is defined as the ratio of signal power to
noise power, often expressed in decibels.
Solo: Choosing one channel to listen to via headphones.
Speakon: This is a trademarked name for an electrical cable/connector. It is
mainly used in professional audio systems to connect loudspeakers to
amplifiers. Other manufacturers make compatible products, often under the name
“speaker twist connector.”
Subgroups: Subgroups are groups of channels that you can “pre-mix” together
before sending them to the Master output mix. For instance, if you use
multiple mics for a drum set, you can combine the channels into a drum
subgroup to control it as if it were one input.
Tip Ring Sleeve (TRS): The parts of the jack plug that the different
conductors connect to. A TRS cable has three conductors vs. the two on a
standard guitar cable. (A guitar cable is a TS or Tip Sleeve cable.)
Unity Gain: This term is used when setting up the balance between pieces of
audio equipment. The idea is that input should equal output level-wise. Audio
that goes into a device at one level and comes out of that device at the same
level is said to be at unity gain.
XLR: XLR refers to a three-pin locking connector used in audio applications.
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