... that would come from a guitar or microphone to a leve

1
Sound Systems

• The Basics and More

2
Basics and More

• The Cost of Safety
• How Sound Travels
• Cables
• Microphones
• Speakers
• Electronic Equipment
• How this relates to musicians
• How this relates to GOD
• Question and Answer

3
The Cost of Safety

• Electrical
• Cables
• Volume Levels
• Dollars and Sense
• Rigging

4
Electrical Safety

• When handling high voltage connectors, grasp
  them with the outside of the hand NOT the inside
• Do NOT unplug a connection by pulling on the cord
• Do NOT lift earth ground connections

5
Electrical Safety

• When you are electrocuted on the hand one of two
  things could happen. Your hand will close up if
  shocked on the inside and will open and pull away
  when shocked on the outside

• Pulling connections by the cord could cause
  electrical shock or damage to the cord or the
  equipment it is attached to
• Lifting the earth ground removes protection for
  you and the equipment designed to use it

6
Cable Safety

• Putting tension on a cord and using tangled cords
  creates hazards
• Stepping on cords damages them and could damage
  the equipment they are connected to

7
Cable Safety

• Look down when walking on a stage and avoid
  running. Keep the cords out of walking areas
• Use extra caution when a stage is dark as most
  cords will become almost invisible

• Do NOT step on or place things on cables. They
  can be damaged by such things as hard soled
  shoes, stands, chairs or other objects

8
Volume Level Safety

• The threshold of pain is 120 decibels and can
  cause temporary hearing loss
• Permanent hearing loss beings at 140 decibels

9
Volume Level Safety

• Avoid long term exposure to high volume levels
  that lead to permanent hearing loss. Examples
  are a live concert or playing headphones loud
  enough that your ears wax within a couple of
  minutes

• Hearing damage caused by high volume levels is
  permanent in most cases. If you feel you need to
  cover your ears or you are beginning to feel
  pressure then this should tell you the volume is
  too high

10
Dollars and Sense

• High quality does NOT always relate to high
  durability
• Properly maintaining the components of a sound
  system can extend their life

11
Dollars and Sense

• Some of the most expensive equipment is also the
  most delicate
• No one product is indestructible

• High quality can come with a high cost of upkeep.
  Ignoring that cost can increase the risk of
  failure and cost and damage to other equipment

12
Rigging

• California seismic code requires that ALL
  overhead rigged lights or other equipment MUST
  have safety cables
• ALL stage props for productions or otherwise MUST
  be fire retardant
• Improper rigging is an insurance claim waiting to
  happen

13
How Sound Travels

• Frequency verses directionality
• Frequency verses perceived volume level

14
How Sound Travels

• Frequency verses directionality
• The lower the frequency the less directional it
  is
• The higher the frequency the more directional it
  is

15
How Sound Travels

• Frequency verses perceived volume level
• The lower the frequency the longer it takes to
  fully develop
• The higher the frequency the less time it takes
  to fully develop

16
Cables

• How they work
• Care and handling
• Different types of cables

17
Cables

• How they work
• They consist of strands or solid wire made of
  either copper, tin, silver or gold. Then these
  wires are insulated with a rubber or plastic
  compound
• Cables can have many of these insulated wires
  together to meet various design needs
• Shielded cables are the same but have stranded
  wire or foil that completely covers the inner
  wire. This outer wire is commonly called the
  ground or shield

18
Cables

• Care and handling
• Kinks in cables are one of the most common causes
  of failure
• Connectors are the second most common cause of
  failure
• Improper wrapping of cable causes tangles and
  leads to cable damage
• Excessive tension or pressure where the connector
  and cable come together is another common cause
  of cable failure

19
Cables

• Different types of cables
• Microphone cables are used primarily for
  connecting microphones to a sound system. These
  commonly use XLR connectors.
• Speaker cables are used to connect speakers to a
  sound system. These use speakon, 1/4 inch,
  banana plug or bare wire connectors depending on
  the installation

20
Cables

• Different types of cables (continued)
• Patch cables are used to connect sound equipment
  together or are used in a patch bay. These use
  1/4, RCA ,XLR or TRS connectors depending on the
  equipment or patch bay design
• AC cables or extension cords are used to connect
  sound equipment to electrical outlets. These
  should be kept away from the other types of
  cables for noise reasons and shouldnt run
  parallel with audio cables

21
Microphones

• How they work
• Care and handling
• Connecting
• Positioning

22
Microphones

• How they work
• They are technically called a transducer. This
  is because they convert one form of energy to
  another. They convert sound waves in the air
  into electrical sound waves that run through wire
• They consist of a diaphragm that moves with the
  sound waves in the air. This is converted by
  inductance or capacitance and then into an
  electrical representation of the sound wave

23
Microphones

• Care and handling
• They should be stored in a dry, well padded case
• They should not be held by the cable unless by
  design
• They should not be hit or dropped
• They should not be used near water

24
Microphones

• Connecting
• Turn off or mute the channel you intend to
  connect the microphone to. Then connect it
• Do not just pull a connector out of a microphone
  without first wiggling the connector. This is
  done to ensure the internal microphone connection
  is not pulled out along with the cord connector
  if it were loose.

25
Microphones

• Positioning
• Do NOT aim a microphone directly at a monitor or
  speaker
• Make certain the microphone follows your mouth
• Angle the microphone at roughly 45 degrees from
  your mouth
• Keep the microphone within two to six inches from
  your mouth
• Do NOT use omnidirectional mics around monitors

26
Microphones

• Positioning (continued)
• Choir or overhead mics should be aimed at the top
  row of singers and placed a few feet from the
  first row of singers. Large choirs or groups
  require more mics using similar techniques.
• Boundary mics should be placed one or more feet
  in front of the speaker on a hard surface at
  waist or chest level or on a floor depending on
  the application.

27
Microphones

• Positioning (continued)
• Lapel mics should be 2 to 3 buttons down on a
  collared shirt. If the mic is omnidirectional
  then dropping down to the 3d or 4th button is
  preferred
• Headset mics should be worn so that the mic is
  aimed directly at the mouth or cheak depending on
  the design

28
Speakers

• How they work
• Care and handling
• Connecting
• Positioning

29
Speakers

• How they work
• They are also a transducer for the same reasons a
  microphone is
• They convert an electrical representation of a
  sound wave into sound waves that move air that
  the human ear can perceive
• They consist of single to multiple cones, domes
  or diaphragms that move air to create sound waves
  by either electrical inductance or capacitance

30
Speakers

• Care and handling
• They should be stored in a dry place
• They should not be driven to the point where
  there is audible distortion
• They should not be under or dramatically over
  powered as these are the most common causes of
  speaker damage

31
Speakers

• Connecting
• They should be connected with the proper gauge of
  wire for the power they will need to operate
  optimally
• Do NOT disconnect speakers while they are playing
  unless the amplifier used can tolerate this
• Do NOT connect more than two speakers in parallel
  to one amplifier unless it is rated to support it

32
Speakers

• Connecting (continued)
• Most average to high quality speakers used for
  sound systems are rated for at least 200 watts.
  It is not uncommon to see 600 or 1200 watt
  ratings. Even if you can connect or disconnect a
  speaker when powered to full output. A word of
  warning. I know of a technician that used a high
  quality 300 watt amplifier for light arch welding

33
Speakers

• Positioning
• The main speakers should be mounted between the
  stage and audience and directed at the audience
• Most speakers are designed to work optimally in
  the upright position with few exceptions
• Whenever possible ALL microphones should be
  behind the main speakers
• When positioning monitors consider the polar
  pattern of the mic you are using

34
Speakers

• Positioning (continued)
• Monitors should be pointed up at the performers
• Avoid excessive monitors to control feedback and
  stage volume
• Do NOT place monitors side by side or within
  roughly six feet of each other
• Subwoofers should NOT be in close proximity to
  mics
• Subwoofers should NOT be given microphone signals

35
Electronics

• How they work
• Care and maintenance
• Powering a sound system
• Using a Cassette Deck
• Using a CD Player
• Using a Direct Box
• Using a Mixer

36
Electronics

• How they work
• Most analog electronic equipment in a sound
  system consists of multiple amplifiers. These
  slowly increase the levels from a small signal
  that would come from a guitar or microphone to a
  level sufficient to power a speaker

37
Electronics

• Care and maintenance
• Equipment should be kept in a dry place away from
  water and dust
• Equipment should be kept away from high power
  wires and motors that are commonly found in
  refrigerators, air conditioners and other similar
  devices to minimize noise and other forms of
  electrical interference
• All equipment should be grounded properly to
  prevent fire and electrical shock hazards

38
Electronics

• Powering a sound system on in order
• Cassette decks, CD players, equalizers and other
  similar equipment
• The Mixer
• The Amplifiers

• Powering a sound system off in order
• The Amplifiers
• The Mixer
• Cassette decks, CD players, equalizers and other
  similar equipment

39
Electronics

• Powering a sound system (continued)
• Devices with moving parts like CD players or
  Cassette decks could react poorly to high
  humidity or cold weather. In these cases leave
  the equipment on roughly half an hour before using

40
Electronics

• Using a Cassette Deck
• If the tape is not wound tightly on the reels
  then use a pencil or other device to remove the
  slack. Some lower quality decks will eat a tape
  for this reason alone
• If the deck does not have auto bias selection
  make sure to pick the right setting
• Do not use metal tapes on decks that are not
  designed for them. This will wear out the tape
  head pre-maturely

41
Electronics

• Using a Cassette Deck (continued)
• To cue a tape rewind the tape to the point where
  the track will start. Play the tape and listen
  for the song to begin. As soon as the music
  starts press Stop on the deck. Remove the tape
  and use a pencil or other device to turn back the
  reel approximately one and a half turns

42
Electronics

• Using a CD Player
• When cleaning CDs use a soft dry cloth and move
  from the inside to the outside
• Keep CDs away from direct sunlight, high
  humidity or excessive heat
• Do NOT write on the top of a CD unless you know
  the pen you are using has no alcohol in the ink
• Do Not place labels off center on the CD as some
  players will not play the disc due to wobble

43
Electronics

• Using a CD player (continued)
• Cueing a CD is as easy as inserting the disc and
  selecting the track and pressing play. Older
  players take longer to start up so selecting the
  track and then pausing the player may help make
  up for this delay

44
Electronics

• Using a Direct Box
• A Direct Box is also known as an Impedance
  matching transformer
• This device should be used when connecting
  unbalanced, high impedance devices to a sound
  system, such as VCRs, TVs, computers, electric
  guitars, keyboards and other similar devices
• Active versions require a battery or can run from
  phantom power
• Lifting the ground should be used only as a
  temporary solution

45
Electronics

• Using a Direct Box (continued)
• This device may not be needed if the cable run is
  under 25 feet and there is a high impedance input
  on the sound system
• These devices come in passive and active
  versions. The active version is more versatile
  and is better at isolating noise
• They are connected to the sound system with a
  microphone cable and connected to a microphone
  input in most cases

46
Electronics

• How to use a Mixer
• This is the most versatile and thus can easily be
  considered the most confusing part of the sound
  system
• Try not to look at the whole board but look at
  the area you need too and focus in from their.
  Much like reading a map you first get the cross
  streets and then the address

47
Electronics

• How to use a Mixer (continued)
• The controls in each channel
• Trim This is the first volume control for the
  channel. It has a very broad range of level to
  cover most every option
• Line/Mic This is a switch to select between the
  line or mic input. This way you can have
  multiple devices on one channel and pick which
  one you want to use

48
Electronics

• How to use a Mixer (continued)
• Phantom Power This is a switch to provide 49
  volts of power for mics or direct boxes that
  require it
• High Frequency Control This is much like the
  treble tone control on your home stereo. It
  adjusts the amount of gain or cut in the high
  frequencies
• Mid Frequency Selection This control allows you
  to pick the frequency you will boost or cut in
  the mid frequency range

49
Electronics

• How to use a Mixer (continued)
• Mid Frequency Control This is much like the
  Midrange tone control on your home stereo. It
  adjusts the amount of gain or cut in the midrange
  frequencies
• Low Frequency Control This is much like the
  Bass tone control on your home stereo. It
  adjusts the amount of gain or cut in the bass or
  low frequencies
• Aux Sends These allow you to direct signal from
  one channel to one of the Auxiliary buses

50
Electronics

• How to use a Mixer (continued)
• Sub Group assignments This allows more control
  over where the signal from the channel will go
• Pan Control This is much like the balance
  control on your home stereo. You can select
  where the signal will go
• Mute This does exactly what it sounds like. It
  mutes the signal coming out of the channel

51
Electronics

• How to use a Mixer (continued)
• PFL This stands for Pre-Fader Level. Use this
  to monitor the signal on the channel and to set
  the channels gain structure
• Fader Control This is the most obvious control
  and once your gain structure is setup you can use
  the fader to control the output level of the
  channel
• Presence Meter This is a small light that
  indicates a signal is present and a peak light
  for when the channel is clipping

52
Electronics

• Gain structure This is critical for good
  mixing. Use the PFL and bring the Trim level up
  until the signal is averaging 0 decibels
• Bus This term refers to the path a group of
  signals travel on

• Clipping This is when the signal has gotten to
  a level where distortion is being created in the
  original signal
• Decibels This is the term used to indicate what
  a signal level is. It is also called dB.

53
Electronics

• Mixing Techniques (continued)
• Setting the Fader
• Not too fast or you may get the unexpected
• Try to keep the fader around 2/3 to 3/4 of the
  way up so you have some room if you need it
• Riding the Fader
• If you must pull someone up/down then wait for a
  quite or down/up tone to make your move

54
Electronics

• Mixing Techniques
• Some basic tips on EQ
• 31 Hz is Woofy
• 63 Hz is Boomy
• 125 Hz is Punch
• 250 Hz is Chesty
• 500 Hz is Honky
• 1K Hz is Nasally
• 2K Hz is Quacky
• 4K Hz is Tinny
• 8K Hz is Spitty
• 16K Hz is Airy

55
Electronics

• How it all comes together
• Sound is picked up by the microphone and is
  converted to an electrical signal
• The signal is carried down a microphone wire to
  the sound system
• Then the signal is passed through a mixer where
  several signals are combined to produce a signal
  with all or some of the other signals combined.
  This is why the mixer is the most powerful part
  of the system

56
Electronics

• How it all comes together (continued)
• Then the signal from the mixer is sent to various
  other equipment such as cassette decks for
  recording and to the amplifiers
• This sound that was sent to the amplifiers is
  amplified enough to power the main speakers or
  the monitors

57
Electronics

• How it all comes together (continued)
• As you can see there is a potential for a loop to
  be created here. This looping is referred to as
  feedback. Feedback occurs when a signal the
  sound system has just amplified from a microphone
  is picked up by the same or other microphone in
  the system again. Thus, the system attempts to
  amplify this again-and again-and again

58
How this relates to musicians

• How to use monitors effectively
• How to use microphones effectively

59
How this relates to musicians

• How to use monitors effectively
• If singing in a group and you are all using one
  monitor then try practicing with all of your
  monitor levels at the same setting
• If singing with an amplified instrument that is
  not run through the sound system try not to get
  in the habit of turning your level up when
  something else does
• If possible stay in line of site with your fellow
  players. Communicate constantly

60
How this relates to musicians

• How to use microphones effectively
• If you want a fuller sound get closer to the
  microphone. However, do NOT eat it unless you
  really want that effect
• If your range in volume changes then try changing
  the distance of the microphone in relation to
  your volume. You do not want to get more than
  six to eight inches away or you will probably
  start to sound very hollow, tinny or distant

61
How this relates to musicians

• How to use microphones more effectively
  (continued)
• If you sing in a choir or large group and have a
  microphone placed above you. Try not to sing
  with your head tilted upward. This causes a
  strained effect in your voice and could cause
  your voice to be over emphasized

62
How this relates to GOD

• Purpose of the Sound System
• Purpose of the Musicians
• How worshiping together achieves a common goal

63
How this relates to GOD

• The purpose of the Sound System
• The sound system is there to amplify and assist
  in creating a spirit of worship in the church
• The sound system operator is NOT a position of
  power

64
How this relates to GOD

• The purpose of the Musicians
• The musicians and singers are there to worship
  GOD and thus assist in creating a spirit of
  worship in the church
• Nobody is there to play solo. They are there to
  worship together as a single voice with
  everything and everyone in their place

65
How this relates to GOD

• How worshiping together achieves a common goal
• The spirit has more freedom to move and work
  through us as HIS instruments
• We are all brothers and sisters in Christ and
  Christ must come first in ALL things and ALL
  things must be done for HIS glory.

66
Reference material

• Web site
• www.churchsoundcheck.com for discusion groups,
  links to manufacturers and more
• Books
• Sound Reinforcement Handbook, 2nd Edition by Gary
  Davis and Ralph Jones
• Guide to Sound Systems for Worship by Jon F. Eiche

67
Sound System Basics

• Question and Answer
• Hands on Training