State Tech Training Fall
Welcome to State-Aud-Con
“State Tech Audio Concepts”
State Tech Plaza
Rigs
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Sound C Sound D (sound c w/ subs)
Extremes
EAW
JBL
DJ Rig
House Sound (VBR, Campanile, Wills, Einstein)
Types of events
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Speeches
Panel Discussions
PowerPoint presentations
Stage Load-ins
International Nights
Banquets
Dances
Bands/Concerts
State Tech Acronyms & Terms
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Most common
FOH – Front of House
Works…our monitor and
VBR – Volstorff Ballroom FOH gear
Media – Equipment rack • Sound C – small/medium
format sound system
with media gear
• Extreme – very small
FX – Equipment rack
format sound system
with effects processors
• DI – direct input
EQ – Equalizer
(unbalanced signal to
Comp/Gate –
balanced signal)
compressor/gate combo
• PCDI – personal
unit
computer direct input
Mic – microphone
EAW – Eastern Acoustic
Locations to Know
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VBR - Volstorff Ballroom
Camp Hope – VBR Booth
135 Hallway/ North Hallway
Loading Dock/Freight Elevator
Data Closet
150 Office Suite
Tech Plaza
001
Market Stage
Campanile/ Hobo Day Gallery
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Lewis and Clark
Jacks Place
Sylvan Green
Frost Arena
Animal Science Arena
Coughlin Alumni Stadium
PAC - Performing Arts Center
Peterson Recital Hall(Lincoln)
The Barn VS DePuy
Storage Unit
Basic components of Sound
Reinforcement
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Sources – Microphones, iPods, Guitar(DI), Etc.
Mixer (Sound Board) – Analog, Digital
Signal Processor – EQ, Delay, Compression, Limiting
Amplifier
Loudspeakers – Active/Passive
Acoustical Environment – Noise/Reflections
Audience – Sufficient sound level (easy) and clarity (hard).
General Setup Goals
(1) Place loudspeakers for even coverage
--Aim for back row
--Minimized coverage overlap
(2) Use Appropriate Interconnect practices
--Use Balanced Cables when possible
--Correct Gauge Cable for Loud Speakers
--Use DI’s for Long distance runs (6’+)
(3) Establish System Gain Structure
-- Set Mixer at 0dB or “Unity”
--Set Amplifiers to Desired Volume.
General Setup Goals Cont.
(4) Verify setup with iPod or CD Tracks
--Music AND SPEECH
-- Walk the audience areas and LISTEN
--This is your goal for the performance.
(5) Connect mics and set levels
--Fader at “zero” or “unity”
--adjust gain to “unity”
--Watch for overload
A Quick note of “unity”
• Unity is in most cases is “Zero” however
“Zero” means a variety of things in different
cases. Most often it is 0dB. dB is only a
reference. dB SPL, dBu, dBFS actually mean
something. However, 0dB SPL is inaudible,
0dBu is generally mix position, and 0dbFS is
just under clipping the system.
General Setup Goals Cont.
(6) Set monitor levels
--Must be at least 10db below mains in house (half
loudness)
--Set house first, leave house up, then set monitors
(7) Details = Ear Candy
--If it does not sound good by now go back to step 1
--EQ Main loud speakers
--Channel EQ, Compression, Effects
--Address micing problems with placement/swapping
--Refine by subtraction – Simplify!
Back to dB
What is dB? A Reference!
Relative: Turn it up 3dB.
Absolute: Set it for 80 db SPL.
Even better: Set it for 80db SPL A weighted Slow
Relative Levels
The Decibel
Perceived Change
dB Change
Power Ratio
No change
0 dB
1x
Perception Threshold
1 dB
1.26x
Minimum
practical change
3 dB
2.0x
Goal for
system changes
6 dB
4x
Twice loudness
10 dB
10x
20 db
20 dB
100x
30 dB
30 dB
1000x
40 dB
40 dB
10,000x
What you need always depends on what you start with!
Absolute SPL
•Sound level change of 1 or 2 dB is barely
noticeable
•Ears need 10 dB SPL to perceive sound as twice as
loud
•100 watt amp sounds twice as loud as 10 watt
amp using same speakers & same distance
•Switching from 100 watt amp to 200 watt amp = 3
dB increase
•1000 watt amp doubles perceived volume from
100 watt amp
Absolute Sound Pressure Levels
(From OSHA, SPL A-weighted slow)
Absolute Sound Pressure Levels
(From OSHA, SPL A-weighted slow)
Absolute Sound Pressure Levels
(From OSHA, SPL A-weighted slow)
Other SPL Factors
•For a given power to a loudspeaker, perceived
loudness depends on:
– 1) Distance between listener &
loudspeaker
– 2) Audio frequency
– 3) Room acoustics
– 4) How well listener’s ears work
– 5) Loudspeaker efficiency
Audio Frequencies - Hearing
• Human hearing ranges from about 20 Hz to 20,000 Hz
• Speech range from about 100 Hz to 4 kHz
• Music fundamentals fall between 40 Hz & 15 kHz
Audio Frequencies - Harmonics
• Audio waveforms contain harmonics or overtones
Audio Frequencies
• Octave - interval between 2 frequencies having 2:1 ratio
• Each doubling of fundamental is an octave
• Audio frequencies cover 10 octaves
• Center for articulation located in the 2kHz Octave
Articulation
State Tech FOH Sound
System Overview
Interconnects
Unbalanced
Pros:
Cheap
Good fidelity
Cons:
Sensitive to any input voltage
No noise immunity
Prerequisites:
Short cables (<1m)
¼” TS Connector
RCA (Phono) Plug
Interconnects
Balanced
Pros:
Good Fidelity
Noise immunity
Polarity easily reversed
Cons:
Polarity easily reversed
More Expensive than Unbalanced
XLR Connector
¼” TRS
Connector
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XLR
Balanced
TRS ¼”
Balanced In or Out
Unbalanced Stereo
Unbalanced Insert
TS ¼”
Unbalanced
RCA
Unbalanced
3.5mm
1/8”
Consumer –
Unbalanced Stereo
Speakon
Loudspeaker I/O
Banana
Loudspeaker I/O
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BNC
Antenna
Aux Lighting
Video
PowerCon
Aux Power
VGA
Standard and High
Definition Video
RS-232
Data
DVI
Common on Mac
video outputs
Mini DVI
Common on Mac
video outputs (Most
current)
Mini
DisplayPort
Common on Mac
video outputs (1st gen
MacBook)
HDMI
High Definition
Digital Video
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The Channel Strip - Signal Flow
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Mid
HIGH
VERY HIGH
1. Close Micing
2. Beta 58 or SM 58
3. Avoid Boosting Filters
4. Watch Monitor Levels for
Feedback
1. Long Gooseneck
2. Avoid Boosting Filters
3. Low monitor levels
1. 3 to 1 rule
2. Vocal Support Only
3. SM 81 w/ Bass Cut
4. No Monitor Feed
LOW
1. Extremely close mic placement
2. Electrical Feed if bass
3. Reduce Stage Level
4. Minimal Monitor Feed
LOW
1. Extremely close mic
placement.
2. Aim at center of head if thin
3. Aim at rim if too boomy
4. Watch levels of overhead mics.
NONE
1 Direct box.
2. Near Max Output Level (90%)
3. Watch for ground loops
4. Good for setting starting level
Mike’s Micing Techniques
• For many applications, keep the microphone
as close to the source as possible
Mike
Hi, I’m
Mike!!!
-Make sure customer speaks
into the microphone with
sufficient volume AND clarity,
and at a very small distance
from the microphone
Mic
Mike’s Micing Techniques (cont.)
• For guitar and bass cabs, place the mic slightly
off-center of the cone and as close to the grill
as possible without touching the grill.
Mike’s Miking Techniques (cont.)
Mike’s Miking Techniques (cont.)
Microphone Specs
1. Sensitivity
The signal level post gain should be sufficient to produce
a “meter zero” indication on the main or solo meter.
The factors that affect this are:
1. Mic sensitivity
2. Source level
3. Mic-to-source distance
4. Gain/Trim setting
2. Pattern
Polar patterns can be used to reject unwanted sound
Microphone Specs (cont)
3. Distance
Close-micing produces improved signal-to-noise ratio and direct to reflected ratio
4. Iteration
The 3 to 1 rule
Only one mic should be used
for each program source (generally).
Large sources may require
multiple mics.
5. Polarity
Microphone Types
Dynamic
General Features
-Passive (No External power)
-Ultra Reliable
-Low sensitivity
-Robust construction
-High SPL
• Tech Microphones include Beta
58, SM 58, SM57, Beta 52, Beta
56, ATM 25
Microphone Types
Condenser
General Features
-Active (Requires power source
AKA phantom power)
-Wide Bandwidth
-High Sensitivity
-On-board filters (sometimes)
• Tech Microphones include SM81,
Beta 87, Beta 98, Podium Mics
Phase Cancellation
• Happens when a single source is 180degress
out of phase. (can happen with only 1 mic!)
Microphone Notes
-Use dynamic mics when possible (more reliable, less loading on mixer, no
pops)
-Mic proximity affects the sound. The closer the better!
-Avoid lapel microphones when possible…AT ALL COSTS!!!
-Compared to lapel mics, head worn mics sound better, provide more gain,
and have less interaction with other mics and reflective sources.
-Use wired mics instead of wireless when possible
Phantom Power
Phantom power is a DC power source, that is originated at the mixer, and
feeds the microphone through a standard mic cable (XLR).
-Current limited by mixer design
-Causes “pops” if interrupted
-Requires shield connection in cable
-48VDC is “standard” but other voltages can work
-Turn off if not needed
-DON’T supply to tape decks, ribbon mics, etc.
-Turn off prior to patching mics
-Needed for active DI’s, unless DI is supplied with a battery
Mixer Gain Structure
1. During the sound check, adjust
each channel trim to produce a
“zero” reading on the main
meter.
This is the minimal level that will
be needed from a single
channel.
Always
-Do this before you set stage monitor levels.
-Don’t readjust trims if you are running the monitors
• For a Quick Setup, Set all the faders to
“Unity” and do a quick mix with the channel
trims.
Inserts
• Line level signal processors can be “inserted” into the
signal chain for individual mixer channels if needed
Insert Processors: Notch Filters, Equalizers, Compressors, Effects
1. Set external device to unity
2. Keep Cables Short
3. Use Sparingly
Dynamic Range Control
Our Compressors
To make a compressor a limiter simply set the ratio to infinity to 1.
General Rule;
If you can hear the limiter, you’re using too much.
If you can’t hear the compression, you’re using too little.
Graphic Equalizers
• Graphic Equalizer. A multi-band variable equalizer
using slide controls as the amplitude adjustable
elements. Named for the positions of the sliders
"graphing" the resulting frequency response of the
equalizer. Only found on active designs. Both center
frequency and bandwidth are fixed for each band.
Equalizer effects
Multiple Filters
Acoustic Feedback Control
Sound Systems “howl” or “screech” when the loudspeaker’s acoustical output
exceeds the level of the signal at the input that produced the output signal. Basically,
the system is amplifying itself.
When feedback occurs…
1. Turn it down!
2. Find the offending mic.
3. Move it closer to the source.
4. Increase the source level.
5. Move or reposition the mic.
6. Reduce the number of open mics,
and/or use gates.
7. Insert a notch filter on the channel.
8. Redesign the loudspeaker system.
Things to avoid:
-Panicking!
-Using graphic equalizers as feedback filters
-Feedback filters in the main signal chain.
Other Tips:
-Turn down monitors or move them
-Use contact pickups when possible
Active/Passive Crossovers
Active 2-Way Crossover
Active 3-Way Crossover
Crossover frequency Response
EAW SM129z
1” Tweeter
12” Low Woofer
Passive 2 – Way System
EAW SM159z
1” Tweeter
15” Low Woofer
Passive 2 – Way System
JBL SR Series
2” Horn Loaded Tweeter
6” Horn Loaded Midrange Woofer
2 – 12” Lowrange Woofers
2 – 15” Subwoofers
EAW KF650z
Active 3-Way System
2” Tweeter
10” Horn Loaded Mid
15” Horn Loaded Woofer
EAW SB528zR
2 X 18” Woofer
Vented Enclosure
Most Common Configuration – KF650z
4-Way System
EAW KF650z Splay
State Tech Training Fall 2015
Customer Service
Clients are generally very nervous about the
events they are in charge of. It is important to
make the client feel as comfortable as possible
to ensure the event’s success.
Click On Me!
The State Tech Script
Hi! My name is (fill in blank). You must be (fill in
blank). I have this, this, and this ready (point
accordingly), and this is your microphone. If
you have any other questions you will find me
in the booth right there (point).
(Exaggerated)
Excuses are like armpits,
everyone’s got ‘em
“It’s not my job.”
People will judge you
by your actions, not by
your intentions.
Attitudes are contagious.
Are yours worth catching?
Amazing customer service can
only be reached when you
make the customer’s needs
your own. When you say “Hi,
right now I am totally at your
service. Whatever you need I
can do. I am all yours.”
For some, this may be
difficult. For others, this
may be impossible. But
for YOU, it is expected.
Each and every one of you
need to do your best at
communicating this
principle.
Respect commands itself and it can neither
be given nor withheld when it is due.
Respect is being considerate and
acting appropriately towards
others no matter the situation.
Display of
dignity and
care towards
everyone.
Be Professional!
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Dress to impress, people watch you!
Put the cell phone away
Look like you’re doing something
Leave the drama in high school