Introduction to Live Sound

You ready?

Lets dig in...

The

channel

strip

features to look for

true diversity

• more than one antenna

remote-mountable antennas

Choosing a wireless mic

frequency agility

• ability to change channels

where am I?

Choosing a wireless mic

not just now, but in the future

Avoiding feedback

avoid interference from TV stations

how many channels will I need?

mic as close as possible

Voices / spoken word

turn EQ on and off to hear what you've done

cutting is better than boosting, but both are useful

A few thoughts on EQ

unless you want to replace it in a few years, buy for what you'll need in the future, not what you need now.

place mics BEHIND the speakers

eq is the last resort

use HPF to cut out everything below 80-120 Hz

ask yourself if that is how the person "really sounds"

mute any mics that aren't being used

Using mics

Feedback

Cost:

Vocals (singing)

More:

using the inverse square law

learning to recognize feedback before anybody else

close or distance miking?

identify and reduce problem frequencies

• "add and subtract"

close - almost always preferred

A few thoughts on EQ

pull out a low end to balance proximity effect

ask "is this how I want it to sound?", not "is it good?"

use HPF to cut out everything below 60-120 Hz

$150 for full course

$35 per class

distance - when a full, natural sound can't be achieved with close miking.

cardioid mic aimed away from monitor

hypercardioid mic aimed away from monitor

distance miking applications:

• drum overheads
• string sections
• choirs

don't fight it - avoid it!

can be full-blown (self-propagating) or partial (ringing)

beware feedback!

Book:

part art, part science

Operating principles

Wireless mics

basics of operation

condenser (capacitor) mics

A few thoughts on EQ

require phantom power

tip #1: don't cover up the antenna

EQ is all about practice and listening

one transmitter per receiver

• just like the FM radio in your car

here's my process for most signals...

• set / turn on high pass filter
• listen in context of mix and soloed for problem frequencies
• use the "add and subtract method" to find offensive frequencies

either handheld or beltpack transmitter

typically most accurate, less coloration

can be dynamic or condenser, any polar pattern

tip #2: don't wrap the cable around the beltpack

The Ultimate Live Sound

Operator's Handbook

applications:

• drum overheads
• acoustic instruments
• some vocals
• any instrument that benefits from distance miking

by Bill Gibson

Kick drum

Week 1 - Introduction

fundamentals of sound

acoustics

art vs. science

the job of the sound engineer

listen for the big three

• boom = 50-60 Hz
• smack = 3 kHz - 5 kHz
• click = 6 kHz - 8 kHz

watch out for mud - 200-500 Hz

use hpf to get rid of sub-sonics, rumble

Week 2 - System overview

A few thoughts on EQ

Operating principles

dynamic (moving-coil) mics

New!

Available at Dave's Music Den

signal flow

sound system components

connections & cables

impedance

levels

microphones & DI boxes

Hands-on: assemble a portable PA system

most durable of all mic types

Private discussion forum

-Ask questions

-Discuss the class

-Go deeper -

learn more!

More:

highest volume handling

3 to 1 rule

stereo miking

ribbon mics

boundary mics

piezo-electric transducers

Plus how to mic:

drums

guitar amps

pianos

choirs

...with a live band

standard choice for most live sound applications

Week 3 - The mixer

layout & common sections

signal flow

channel strip

inputs and outputs

digital vs. analog mixers

Hands-on: try out several popular analog and digital mixers in our mixer petting zoo.

applications:

• vocals
• most drums
• guitar cabinets
• any loud instrument that needs to be close-miked

Week 4 - Amps and speakers

once you've isolated the source, EQ it out

backing off the main fader just a few dB is usually enough to eliminate ringing

if you're not sure where it's coming from, it's probably the last thing you touched

Feedback

step one - kill it before it multiplies

• train your ear to recognize ringing before it becomes full-blown feedback

what if it happens anyway?

powered vs. passive speakers

line arrays

monitoring

speaker processing

power up / down sequence

Hands-on: set up a digital speaker processor on our portable system

6- Week

Live Sound

Workshop

More...

back panel / jack field

digital mixers

built-in effects

mute groups

why not?

Week 5 - Signal processing

Wireless mics

compression / limiting

EQ

reverb

live recording

Hands-on: try each type of processing discussed and hear what it does to the signal

Week 6 - Putting it all together

cost

• typically 5X the price of a comparable wired mic

sound quality

• a $1,000 wireless system still doesn't sound as good as a $25 cable

reliability

• all the same same problems as wired mics plus a world of new ones

regulation

• the FCC has LOTS to say about wireless mics

power up / down sequence

gain structure

mic technique for vocals, guitars, and drums

how to run a sound check

building a mix

Hands-on: Set up proper gain structure on our system, and mic up a band

Tuesdays

Sept 29 - Nov 3

6:30 pm

-OR-

Saturdays

Oct 3 - Nov 7

10:00 am

BONUS - Mixing lab!

After each participant will run a sound check and set up a mix on the VENUE console in Sweetwater's Performance Theatre

These are important!

Directional characteristics

every mic has a polar pattern

Omni-directional

So much more...

• guitars
• snare
• drum overheads
• creating sonic space for each element with eq
• eq as an effect

The master section

Others:

Cardioid

bi-directional

sub-cardioid

hypercardioid

shotgun

variable

Super-cardioid

Wireless mics

why wireless mics?

So you wanna be a sound guy / girl?

• cleaner stage
• allows us to place mics where we couldn't otherwise (lapels, headworn)
• performers are free to roam

Let's take a tour, shall we?

The mixer

Microphones

• qualifications:
• do you love music?
• did you ever take apart your toys when you were a kid?
• do you want to help other people succeed?

the most important thing to understand in the entire system!

fortunately, it's not as complicated as it looks...

how to get great sounds from your mics?

use the right mic for the source

place it / use it correctly

Congratulations, you qualify!

the secret I probably shouldn't tell you...

you don't need $100,000 worth of esoteric mics.

The mixer

Other duties

Duties of a sound engineer, continued

Duties of a sound engineer

Microphones

be punctual

• (that means be early.)

wireless

wired

Instruments

through DI boxes

What's a DI Box?

reduces the level and impedance of a signal to mic level

balances an unbalanced signal

to connect instrument or line-level gear to a mic input on a mixer

to make long cable runs possible

why?

Processing

be prepared!

• work with performers, venue
• assemble input list, stage layout
• know how much power you will need and where you'll need it.
• schedule load in, soundcheck, load out
• have the right gear
• wire racks in advance

• Manager
• Caterer
• Driver
• Counselor
• Diplomat
• DJ
• Video operator
• Lighting operator
• Negotiator

• Stage Manager
• Ticket taker
• Promoter
• Accountant
• Janitor
• Public relations
• Guitar tech
• CD / Merch sales
• Electrician

reverb / effects

Sources

take care of the gear

• set it up,
• strike it,
• transport it,
• store it,

...like it's yours, even if it's not.

Line level source

connected directly

Introduction to Live Sound

compression

speaker processing /

feedback suppression

system eq

work with the musicians

• get to know the director and band.
• attend rehearsals and know the music!

commit to excellence

• Learn what a good mix is and practice!

Texas Playhouse Theater

Baylor University

...and a bunch of bands you've never heard of.

Started in 2001

So - a funny thing happened one day at church...

Introduction

Jeff Barnett

The big

picture

Monitors

in-ear monitors

Amplifiers

Speakers

Levels, connections, & cables

floor monitors

audio signals are quantified by:

• whether they are balanced or unbalanced
• their level (voltage)
• the types of connectors commonly used
• their impedance
• (not enough time to discuss today)

line array

passive

active

Levels, connections, & cables

Speaker signals

amplified signal from amp to speakers - highest voltage of all audio cables

Dual Banana

always unbalanced

1/4 Inch TS

takes line-level signals up to speaker level

one of the few things in a sound system that can hurt you!

• heavy
• high current
• can overheat if used improperly

SpeakOn

all speakers need an amplifier

Line level signals

Amplifiers

buy good ones, don't overload them, and you'll be fine.

interconnects between equipment

wattage ratings are important, but don't choose an amp based on that alone

1/4 Inch

TRS

can be balanced or unbalanced

RCA

multiple drivers dedicated to different frequency ranges - 2-way, 3-way, etc.

in essence, a speaker is a dynamic microphone in reverse

• turns electrical current into acoustic vibration

1/4 Inch TS

Monitors

XLR

Instrument signals

primarily used by guitars

Speakers

almost always unbalanced

*...but come with a whole bunch of challenges of their own. no magic bullets here.

Microphone signals

connect mics and DI boxes to preamps - lowest voltage of all audio signals

almost always balanced

Lots more...

snakes

digital signals

multipin connectors

constant-voltage

cable types

how to wrap and store cables

often has customized signal processing to make the speaker / amp combo sound as good as possible

Monitors

amplifier is built in to speaker

requires an external amplifier

less stuff to carry to the gig!

Passive speaker

most common type

Active speaker

requires AC power

Got it?

Moving on...

better control over where the sound goes (and where it doesn't)

more even volume from front to back of audience

consists of multiple speakers arrayed vertically

can be passive or active

Line array