FUMC Sound Tech Course Session 2

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FUMC Sound Tech CourseSession 2

• EQUIPMENT
• Cables Connectors,
• Microphones,
• Speakers Spkr Systems

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Sound Techs Job

• Maximize Worship Experience for attendees
• Everyone can clearly hear Pastor/speakers on the
  Podium
• Song Service is musical and encourages
  participation
• No glitches that distract from mood of the
  Service
• Know sound equipment operation
• Set up sound equipment for services
• Maintain sound equipment
• Protect sound equipment

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Your PERSONAL Ministry

• We hope you view your Sound Tech service as your
  personal gift to God
• Great way to use your talents
• FUMC needs your service
• Mature spiritually
• Be a faithful Servant
• Train Mentor others

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This is a BLOCK DIAGRAM
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Block Diagram of Typical FUMC System
Main Spkrs
Floor Pockets
Mic/Signal wires
Main Out
Mon Out
Amp Rack
Main Spkrs
Signal Process Rack
MIXER
Wireless Mics
Mon Spkrs
Mon Spkrs
Amp Room
Stage
Sound Booth
Flown Stage
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Professional Sound Equipment

• What makes equipment Pro?
• Adding the word Pro to the description
• Raising the price
• What is the REAL difference between
• Consumer sound gear
• Professional sound gear?

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Equipment Differences

• Pro Audio gear
• Higher cost
• Heavy Duty Construction
• 19 Rack Mounting
• XLR or ¼ Connectors
• Plug-in Power Cord
• Duty Cycle High, on for long periods of time,
  played at medium to high signal levels
• BIG systems, Equipment separated by 100s of feet
• Low Impedance Ins/Outs
• 600 Ohms (Balanced)
• High signal levels gt4 to 24dBu (1.23 to 12.3 V)

• Consumer Audio gear
• Lower Cost
• Lightweight construction
• Sits on a shelf
• RCA Connectors
• Wired Power Cord
• Duty Cycle Low, played at low or medium signal
  levels
• Small systems, Equipment adjacent, 1-10 ft apart,
  in a Den or Family Room
• High Impedance Ins/Outs
• 10-50 KOhms (Unbalanced)
• Low signal levels gt -10 to -16dBu (0.123 to 0.245
  V)

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Types of Audio Cables

• Unbalanced (Coaxial, Instrument)
• Single center conductor w/ Shield
• Very Susceptible to Electric/Magnetic Fields
• Used only for short runs
• Balanced (Twisted Pair, Shielded)
• Signal is on 2 wires w/ inverted polarity
• Inherently less susceptible to noise
• Suitable for long runs
• Balanced (Twisted Pair, NO shield)
• Speaker wiring
• Common Mode Rejection
• Noise added to each signal wire
• Amp subtracts out noise

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Rules for running Audio Cables

• Use Balanced cables whenever possible
• Dont run audio cables near power cables power
  components if possible
• No audio cables and power leads in same cable
  bundle or conduit
• Dont run audio cables PARALLEL to power
• Audio cables should CROSS power at right angles
• Make sure you dont use unshielded Speaker cable
  when you need shielded Instrument Cable

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Cable Care Cable Problems

• Cables are prone to damage in 2 places
• Just behind the connector
• A broken wire inside a connector
• For a noisy cable, manipulate (bend/move) it to
  find bad spot
• Set aside a suspected Bad or Noisy cable mark
  it so
• So we can repair it or replace it
• NEVER twist a cable when coiling it
• Use velcro tie to secure coiled cable
• NEVER sling around a mic with its cable
• NEVER bend a cable in more than a gentle arc
• If NO SIGNAL from a cable, try another cable
• We have a Cable Tester located in the CLC Cave

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Connectors

• RCA Unbalanced
• ¼ Phone plug (Mono) also (TS) TTip SSleeve
• - Unbalanced
• ¼ Phone Plug (Stereo) also (TRS) TTip
  RRing SSleeve
• - Balanced
• XLR Pin1Shield Pin2Positive
  Pin3Negative
• - Balanced
• Locks onto mating connector
• SpeakOn
• Banana
• Used for Speakers

XLR Connector
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Connectors (Continued)

• Advantages of XLR Connectors
• 3 pins for balanced cables
• Heavy Duty
• Locks on to equipment for reliable connections
• Shield Pin1 makes contact 1st to bleed off static
  charges (no pops)
• Excellent strain relief for cables
• Wiring color codes
• Black Negative
• White/Rd/Color Positive
• Braid Shield
• Wire color doesnt REALLY matter as long as you
  are consistent at each end of the cable

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Pro or Consumer Amplifier?
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Microphone Types

• Handheld/Vocal
• Close range for individual singer/speaker
• UniDirectional - Cardioid or Hypercardioid
  pattern
• Feedback rejection
• Lavalier
• Close range
• Omni or Cardioid pattern
• Small
• Stand/Drop Mounted
• Group pickup
• Longer range
• Recording (high quality)
• Cardioid pattern

• Over-the-Ear
• Pastors, Speakers
• Noise Feedback rejection
• Contact
• Guitar, Piano
• Pressure Response
• Boundary mic
• Shotgun
• Long range
• Noise cancelling
• High noise environments
• Actually 2 mics out of phase

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Transducer Types

• Dynamic
• Made like miniature speaker w/ coil magnet
• Warm response Preferred by singers
• Condenser
• Made to form a capacitor (condenser)
• Gold sputtered diaphragm acts as capacitor plate
• Requires amplifier voltage supply (phantom
  power)
• Excellent frequency response
• Small vs. Large Diaphragm
• Electret condenser
• Permanently charged diaphram
• Small cheap

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Transducer Types - Continued

• Ribbon
• Metal ribbon suspended between magnet poles
• Flat frequency response - Great recording mics
• Expensive
• Carbon
• Earliest type, used in telephones until recently
• Carbon granules form resistance element
• Poor frequency response but very rugged
• Piezoelectric
• Diaphragm connected to piezoelectric material
• Cheap low cost mics of a few years ago
• Crystal or Ceramic mic

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Mic Pickup Patterns

• Omnidirectional (Omni)
• Equally sensitive in all directions
• Cardioid (heart shaped)
• Directional
• Most popular
• Very little pickup directly behind
• Hypercardioid
• Reduces side pickup
• Has some pickup directly behind
• Proximity effect
• Bass boost when mic is very close to source
• Only in directional mics (not omni)

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Important Mic Specs

• Sensitivity
• Ex -47dBv _at_ 94dB SPL
• Maximum SPL (overload)
• Ex 140 dB SPL
• Frequency Response
• Ex 50-15,000 Hz /- 6dB
• Look for response curve
• Impedance
• Low
• Most Pro mics, lt 150 Ohms
• Tolerate long cable runs
• Balanced output
• High
• Low Cost Piezo/crystal mics
• 25,000 Ohms or greater
• Unbalanced Cables up to 20 ft

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Wireless Mics

• System consists of
• FM Transmitter
• FM Receiver
• Best are Dual Diversity (switches between 2
  receivers w/ 2 antennas)
• Best are UHF (500-900 MHz)
• Lower cost are VHF (150-200 MHz)
• Best are tunable frequency, otherwise are fixed
  frequency
• Controls
• Transmitter
• On/Off, Mute, Frequency select, Mic Sensitivity
• Receiver
• Squelch level, Frequency Select, Audio Output
  level
• Metering-RF signal strength, Audio level, Muting,
  Battery low

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Guess the Frequency Game

• Important that you can pick out frequency content
  so you can EQ properly.
• Choices
• 50 Hz
• 100 Hz
• 315 Hz
• 1000 Hz
• 2 KHz
• 3.15 KHz
• 6.3 KHz
• 10KHz

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• End of Session 2
• Questions or Comments?

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Speakers

• Convert electrical sound signals back to Sound
  Waves
• Electromagnetic Transducers
• Fixed Magnet w/ Moving Coil
• Large magnet higher power
• Semi-rigid cone w/ corrugated surround
• Piezoelectric Transducers
• High Frequency Drivers (Tweeters)

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Low Frequency Drivers

• Low frequencies require moving lots of air
• Electromagnetic Transducer
• Large Diaphragm Area
• Long Diaphragm Excursion (Long Throw)
• High power handling
• Heavy Magnet structure
• Large Diameter Voice Coil w/ large wire
• Rigid frame
• HEAVY!

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High Frequency Drivers

• Types
• Cone, Dome, Piezoelectric, Horn
• Short cone movement
• Low power required
• EASILY DAMAGED by high volumes, Amp clipping
• Consumer speakers use Cone, Dome, Piezo HF
  Drivers
• Provide as wide dispersion of sound as possible
• Pro Speakers use Horn HF Drivers
• Provide CONTROLLED dispersion of sound
• Common units are 40V X 60H and 40V X 90H degrees

Typical Constant Directivity Horn
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Pro Speakers (Cabinets)

• 2 or 3 Drivers per cabinet
• Called 2 Way or 3 Way
• Low Frequency Driver (woofer)
• Mid-Range Driver
• Hi Frequency Driver (Horn)
• Bass Reflex Cabinet
• Box is tuned to LF Driver with Ports to extend
  low frequency response

Typical 2-Way Pro Speaker
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Crossovers

• Separate out proper audio frequencies to send to
  each Driver
• Passive (High level)
• RLC network inside speaker cabinet
• One Amplifier output wire pair drives entire
  cabinet
• Brute Force method
• Not most efficent
• Active (Low level)
• Electronic Crossover separates the various
  frequency bands
• Separate Power Amplifiers for Low, Mid, High
  frequency Drivers
• Multiple amp output wire pairs to speaker cabinet
• Efficient
• Used in Concert Touring systems

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Crossover Frequency Response Curves
Idealized 2-way crossover response
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Speaker Specs

• Frequency response
• Ex 60 15,000 Hz /- 6dB
• Impedance (nominal)
• Ex 8 Ohms, 4 Ohms
• Power Handling (Watts)
• RMS Constant sine wave
• Program Double RMS
• Peak 4 X RMS

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Speaker Specs

• Sensitivity
• Example speaker sensitivity spec
• 95 dB SPL _at_ 1 meter with 1 Watt Input
• What is SPL _at_ 1 meter with a 100 watt amplifier?
• What is SPL _at_ 16 meters with the 100 watt
  amplifier?
• Speaker Beamwidth
• Degrees (Horizontal Vertical) vs. frequency

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Speaker System Design

• Arrange speaker cabinets in Arrays to provide the
  required room coverage
• Direct sound at the audience, NOT at walls
• Minimize sound reflections
• Provide as constant SPL ( frequency response) as
  possible across room
• Use Main cabinets in front and fill cabinets as
  necessary
• Use Time Delay units to drive rear fill
  cabinets to account for closer speaker placement