Live Sound 101.

Live Sound 101

General Audio Terminology
FOH -Front of House Where the audio is mixed for the audience. Typically located at the back of the venue in front of the main speaker system Monitor World- Where the monitors are mixed for the band Typically located at the SL side

Upstage Stage Right Stage Left Downstage Audience

Decibel- dB Unit of measure for Audio Signal in Volts or Electrical Energy Measure of SPL (Sound Pressure Level) in Acoustics Ambient SPL is around 60dB Average rock concert is around 105dB to 110dB When is it too loud? It’s our job to control the SPL! For every 6dB increase the perceived volume is doubled 0dB=Unity Gain -20dB Mic Level Signal -10dB Consumer Line Level (DVD Player, CD Player) +4dB Line level signal (Pro level output)

Signal Flow- Understanding of audio how signal is moved from the source to the audience members ears!

General Audio Design

General Audio Design Types of Audio Systems
Passive (or non-powered) speakers need to be powered by a separate power amplifier or a powered mixer. The power rating of the amplifier or powered mixer is matched to the speakers so they can only ever be used as a complete system Active (or powered) speakers have an amplifier built into them so that they do not need a separate power amplifier. This makes them more versatile in that you can use one speaker on its own, or easily daisy chain more speakers or subs on without worrying about the power implications or Ohmage. This makes them simple to use, and great for bands playing in different sized venues.

Active Two- Way or Bi-Amplified

Active Three- Way or Tri-Amplified

General Audio Design Implementation: Type of event-
Corporate event with a Podium Rock Concert with Full Band Theatactrical Performance Coverage requirements- Type of Venue Church, Bar, Convention Center Coverage requirements? Width, Length, Balcony

General Audio Design Implementation: Type of system: Stacked Flown
Tripod Stand

General Audio Design Implementation: Speaker Coverage
Common Horizontal Coverage Pattern for Speakers: 90 degree 60 degree 45 degree 30 degree Be careful for overlap of patterns because frequencies will cancel!

Some systems utilize zones Left Right Center Cluster Front Fill Delay

Some systems utilize zones- Left Right Center Cluster Front Fill Delay

General Audio Design Implementation: Speaker Coverage-
Avoid placing speakers behind the talent! Feedback is likely!

Mixer Terminology

General Mixer Terminology
-Mixers-Consoles-Desk- It’s the thing with all the knobs and buttons Mixer Types: Analogue- Basic to advanced functionality Digital- Offer lot’s of tools in a small package Powered- Has built in amplification

Input- Most professional and semi-pro mixers will accept mic and line level input It’s where the sound comes in Inputs can be mono or stereo Inputs can be balanced XLR jacks Inputs can be balanced tip ring sleeve ¼ inch Inputs can be unbalanced tip sleeve ¼ inch Inputs can be RCA

Output- Most professional and semi-pro mixers will output line level signal It’s where the sound comes out Outputs can be balanced XLR jacks Outputs can be balanced tip ring sleeve ¼ inch Outputs can be unbalanced tip sleeve ¼ inch Outputs can be RCA

Fader Term used to describe the slider which controls the amount of signal sent to the main outputs Pre Fader Term used to describe how signal is routed to aux busses Signal is taken before the fader. The fader does not need to be up to pass signal Monitors are typically mixed pre-fader Post Fader Signal is taken after the fader. The fader must be up to pass signal Effects are usually routed post fader from an aux (mix) buss

Busses Term used to describe output designation on console. ie. “I assigned the microphone to mix buss #1” Types of mix busses Aux Bus Used to process signal received from mono or stereo input channels Typically used to send signal to monitors or effects devices Can be configured pre or post fader Matrix Bus Used to process signal received from mono and stereo input channels Used to process signal received from mono & stereo outputs

Types of mix busses Mono Buss Process signal received from mono input channels Can be used in and Left – Center - Right Situation Stereo Buss Processes signals received from mono and stereo channels. Often serve as main outputs

Gain (Trim) “Gain staging is the process of setting the gain stage of a mixer or sound system to achieve the best compromise between noise and distortion” -Bruce Bartlett A knob which controls the amount of signal received from an individual input or preamp 0dB= Unity on most analogue professional mixers Head Amp/HA Term which is commonly used to describe input gain control on digital consoles -18dB = 0dB on most digital mixers

Phantom Power Applies +48 volts DC to active devices such as condenser microphones Phase/Polarity Switch on a mixer which reverses the electrical polarity of an input and the phase of a signal Reverses pins 2 and 3 Pin 2 is commonly referred to as the hot or positive pin Pin 3 is commonly referred to as the cold or minus pin

Dynamics Processing Compression Signal processing which automatically changes the gain to maintain a preset level ratio or relationship between the loudest and quietest signals i.e. a 3:1 compression ratio means that for every 3dB a signal increases it will be decreased by 1dB Expansion Signal processing which automatically enlarges or enhances softer parts of a signal

Gate Signal processing which removes noise or signal below a certain threshold i.e. it will takes a certain amount of pressure to open a door and walk through it Ducking dynamic processing effect that reduces level of one signal when a different signal crosses a threshold. most typically used to reduce the level of background music when a voice-over or other signal is present.

Effects Reverb Digital signal processing which simulates acoustic space Hall- Plate-Room are examples of commonly used reverbs Delay Digital signal processing which delays or repeats a signal per a given value Pitch Digital signal processing which harmonizes a signal in + or – cents (steps) 12 steps positive or negative = one octave i.e. a C note can be harmonized by a third to E

Equalization A system of electronic filters used to modify the frequency response of signals Filters can be fixed or variable Graphic Equalizer (GEQ) Commonly referred to as 1/3 octave equalizer Can be 31 band graphic or 15 band graphic Fixed a fixed bandwidth are adjusted 1K to 2K is a full octave Shelf equalization

Parametric Equalizer (PEQ) Allows adjustment of multiple frequency (filters) points Allows adjustment of frequency bandwidth Commonly used on professional mixers for channel equalizer Sweep equalization HPF- Hi Pass Filter (HPF) Can be fixed or variable a HPF filter at 125 Hz will only allow frequencies above 125 Hz to pass LPF- Low Pass Filter (LPF) a LPF filter at 1K will only allow frequencies below 1K to pass

Insert Term used to describe the routing of a signal to and from a channel or output Insert points can be pre or post EQ Insert points or typically post the gain stage i.e. I inserted a compressor on the lead vocal Graphic equalizers on digital consoles are inserted on outputs

Subgroup Commonly used on professional analogue mixers to group instruments or vocals onto a single group. VCA Voltage Controlled Amplification Commonly used on professional analogue mixers to group instruments or vocals onto a single group Applies voltage to selected channels to increase or decrease output not the same as a subgroup DCA Digitally Controlled Amplification Term used to describe digitally grouping of input channels into a single group

Mute Group Term used to describe muting multiple inputs or outputs with a single touch i.e. I have my vocal channels on mute group #1 and the drums on mute group #2 PFL = Pre Fader Listen Routes individual channel or output signals to meter bridge and to the headphone buss for listening Signal is routed pre-fader AFL- After Fader Listen Signal is routed post-fader

CUE Term used to describe selection of individual inputs, outputs or groups for the purpose of visual metering or monitoring via listening. Cur can be set Pre-Fader (PFL) or After-Fader (AFL) Solo to Mix Function which routes cued channels to the main stereo buss for monitoring purposes. Commonly used during a line check Mutes other signals which are also assigned to the main stereo buss Don’t use this function during a show! Last CUE Prioritizes the last channel or output which has been selected for cue

Encoder Term used to describe a knob on digital consoles which changes values of a set parameter. Encoders can rotated or pushed Multi Function Encoder Term used to describe a knob on digital consoles which changes values of a variety of parameters.

Parts/Sections of a Mixer
Rear Panel 6 7 1 2 3 4 5 1. Input External PSU Plug/AC In/On-Off Switch 3. Card Slot Inputs 4. Omni Output Input Digital I/O Section/Midi/World Clock 7. Stereo Input

Digital Mixing Advantages of Digital Mixing
Allows customized work surface for the user Mixers can be configured for a variety of uses Mixers can be set up for many applications Easier to interface with other digital devices and formats Allows shows to be set up at the users convenience via software Allows users to save configured shows to PC or portable memory device Less trouble shooting of external cabling problems between console and processing racks Smaller footprint Easier on the back!

Digital Mixing Disadvantages of Digital Mixing
Digital mixers can sometimes offer too much flexibility Can overwhelm the user Learning curve for users who are used to analogue mixing consoles Displays can be difficult to see in ambient or daylight situations Basic computer networking knowledge is required Smaller footprint can bruise some users egos! Too many digital formats to be standardized Digital distortion us ugly! Not too may user serviceable parts inside

Thoughts Mixing requires experience!
The more you do it the better you will get! Just because it can does not mean you should! Research product before using it. Be sensible Learn through exploration! Have fun!

Live Applications Hands on time

Microphones Dynamic Microphone-
A microphone design where a wire coil (the voice coil) is attached to a small diaphragm such that sound pressure causes the coil to move in a magnetic field, thus creating an electrical voltage proportional to the sound pressure. Works in almost the exact opposite of a dynamic loudspeaker where an electrical voltage is applied to the voice coil attached to a large cone (diaphragm) causing it to move in a magnetic field, thus creating a change in the immediate sound pressure

Microphones Condenser Microphone-
Microphone design where a condenser is created by stretching a thin diaphragm in front of a metal disc (the backplate). By positioning the two surfaces very close together an electrical capacitor is created whose capacitance varies as a function of sound pressure. Any change in sound pressure causes the diaphragm to move, which changes the distance between the two surfaces. If the capacitor is first given an electrical charge (polarized) then this movement changes the capacitance, and if the charge is fixed, then the backplate voltage varies proportionally to the sound pressure. In order to create the fixed charge, condenser microphones require external voltage (polarizing voltage) to operate. This is normally supplied in the form of phantom power from the microphone preamp or the mixing console.

Microphones Polar Pattern- Cardioid Shure SM58

Microphones Polar Pattern- Dynamic Cardioid Shure SM57

Microphones Polar Pattern- Dynamic Super Cardioid Shure SM87

Microphones Polar Pattern- Condenser Cardioid Shure KSM32

Microphones Polar Pattern- Dynamic Super Cardioid Shure Beta 58

Microphones Polar Pattern- Dynamic Cardioid- Large Diaphragm
Shure Beta 52

Microphones Polar Pattern- Condenser Half-Cardioid- Shure Beta 91
Boundary

Microphones Polar Patterns-
Placement is important. Technique is important. Shure Beta58

Microphones Polar Patterns-
Proximity Effect is a consideration when using cardioid and super-cardioid microphones Omni-directional microphones have no or very little proximity effect. These will be discussed more during wireless microphone instruction

Direct Boxes: It converts a high impedance signal to a low impedance signal (although it will also accept a low impedance signal from a preamp, keyboard, active pickup or other electronic device) It converts an unbalanced signal to balanced. It reduces a strong instrument or line level signal (and sometimes even speaker level signal) to a mic level signal suitable for connection to the mic input of a mixing console. It isolates electronic equipment on stage from the mixing console, which can help eliminate interference and noise caused by electrical interaction or ground loops. It also blocks phantom power sent from the mixer so it cannot interact with the the device connected to the DI's input. There are two types of direct boxes. Active and Passive. Active direct boxes require phantom power!

Cable Management When wiring a stage start at the snake or floor input and work towards the source. Leave slack at the base of the mic stand. This make troubleshooting and moving the mics around much easier. Make it look neat. This will make you look like a pro! This will also make the gear last longer. Keep your cables wrapped in nice coils. No fire hoses! No arm wraps! Practice over-under and over-over wraps Educate others and tell them what your expectations are! Enforce a No Duct Tape zone! Use Gaff Tape

Expect feedback and be prepared to combat it!
Hands on time! Experiments: Set up a sound system with one speaker on a stand. Hook up several microphones into the system. (remember the signal flow) Find unity gain on each input (remember to use the cue or PFL function).Leave the EQ flat. Listen to several microphone types both with headphones and in the sound system. Have your partner move the microphone around while speaking. Listen for proximity effect and the polar pattern. After you each listen, EQ each microphone and bring each mic live into the system. Get as much gain before feed back as possible. Try doing the same thing except with the speaker serving as a monitor. Expect feedback and be prepared to combat it!

Dynamics Dynamics Processing Compression Signal processing which automatically changes the gain to maintain a preset level ratio or relationship between the loudest and quietest signals i.e. a 3:1 compression ratio means that for every 3dB a signal increases it will be decreased by 1dB

Dynamics Dynamics Processing Compression (Squash)
Threshold - how loud the signal has to be before compression is applied. Ratio - how much compression is applied. For example, if the compression ratio is set for 6:1, the input signal will have to cross the threshold by 6 dB for the output level to increase by 1dB. Attack - how quickly the compressor starts to work. Release - how soon after the signal dips below the threshold the compressor stops.

Dynamics Dynamics Processing Compression (Squash)
Knee - sets how the compressor reacts to signals once the threshold is passed. Hard Knee settings mean it clamps the signal straight away, and Soft Knee means the compression kicks in more gently as the signal goes further past the threshold. Make-Up Gain - allows you to boost the compressed signal as compression often attenuates the signal significantly. Output - allows you to boost or attenuate the level of the signal output from the compressor

Compression parameter guidelines for popular musical instruments.
Dynamics Dynamics Processing Compression parameter guidelines for popular musical instruments. Attack Release Threshold Ratio Knee Full track Fastest possible Fastest possible or Auto -5dB to -9dB 2:1 to 3:1 Soft Drums 5ms 10ms or Auto -15dB 5:1 to 8:1 Hard Synth Bass 4ms to 10ms 10ms -4dB to -8dB 4:1 Real Bass -2dB to -10dB 8:1 Vocals Fastest Possible Lowest possible or Auto -3dB to -8dB 4:1 to 12:1 Brass Instruments -10dB to -14dB 2:1 to 8:1 Hard or soft Guitars -8dB to -14dB

Dynamics Dynamics Processing Gate (Noise Gate) Gate
Signal processing which removes noise or signal below a certain threshold i.e. it will takes a certain amount of pressure to open a door and walk through it Typically used on drums in live sound reinforcement. Can be used on an effect to create a gated reverb

Effects Reverb A reverberation, or reverb, is created when a sound or signal is reflected causing a large number of reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space Digital signal processing which simulates acoustic space Hall- Plate-Room are examples of commonly used reverbs Can be used to create space in a mix

Effects Delay Digital signal processing which delays or repeats a signal per a given value Can be used to “fatten” up vocals or guitar in a mix Can be used as special effects Pitch Digital signal processing which harmonizes a signal in + or – cents (steps) 12 steps positive or negative = one octave i.e. a C note can be harmonized by a third to E

Equalization Graphic EQ (1/3rd Octave)-
Typically used on main, matrix or auxiliary outputs

Equalization Graphic EQ (1/3rd Octave)- Incorrect

Equalization Graphic EQ (1/3rd Octave)- Look cool but incorrect!

Equalization Graphic EQ (1/3rd Octave)-
Should be used to cut what we don’t want to hear!

Equalization Parametric Equalizer (PEQ)
Allows adjustment of multiple frequency (filters) points Allows adjustment of frequency bandwidth Commonly used on professional mixers for channel equalizer Sweep equalization

Channel Equalization Vocals Parametric Equalizer (PEQ)
Common EQ Curves Vocals SM58 Good starting point! HFP is set around 125Hz

Channel Equalization Bass Drum (Kick) Parametric Equalizer (PEQ)
Common EQ Curves Bass Drum (Kick) Beta 52 Good starting point! Make note of the 4.25K boost to gain attack Mic placement is important

Channel Equalization Snare Parametric Equalizer (PEQ) Common EQ Curves
SM57 Good starting point! HPF around 140Hz Mic placement is important

Channel Equalization Parametric Equalizer (PEQ) Common EQ Curves
Hi-Hat Condenser Good starting point! HPF around 400Hz

Channel Equalization Rack Toms Parametric Equalizer (PEQ)
Common EQ Curves Rack Toms EV468 Good starting point! Mid-Range Cut HPF around 100Hz

Channel Equalization Floor Tom Parametric Equalizer (PEQ)
Common EQ Curves Floor Tom EV468 Good starting point! Mid-Range Cut Similar curve to a bass drum

Channel Equalization Electric Bass Parametric Equalizer (PEQ)
Common EQ Curves Electric Bass Good starting point! Direct Box Pretty Flat

Channel Equalization Electric Guitar Parametric Equalizer (PEQ)
Common EQ Curves Electric Guitar SM57 Good starting point! HPF around 140Hz

Hands On

Wireless Microphones (RF)
Wireless Microphones operate in the following bands: VHF Very high frequency (VHF) 30 MHz to 300 MHz UHF Ultra high frequency (UHF) 300 MHz- 3 GHz

Wireless Microphone Prohibitions by the FCC The operation of wireless microphones and similar devices is prohibited from certain frequency bands for public safety reasons and commercial concerns. The sale of wireless microphones or similar devices intended for use in the United States in the 700 MHz Band was banned by the FCC in January 2010, and use of the devices in the 700 MHz Band was prohibited as of June 12, “Similar devices” include wireless intercoms, ear monitors, audio instrument links and cueing equipment. The 700 MHz Band – between 698 and 806 MHz -- is now reserved for use only by public safety groups, such as police, fire and emergency services, and commercial providers of wireless broadband services. Use on broadcast bands outside of the 700 MHz Band was not affected by the ban, and can continue. Microphones and similar devices with cords are not affected by this prohibition.

RF System Components Receiver Part of the system that receives the transmitted audio signal. Typically has an XLR output to connect to the mixer Transmitter Transmits the signal from the microphone element. Can be a hand-held transmitter (HH) or belt-pack transmitter Microphone Element Connects to either the belt-pack transmitter or the HH transmitter. Can be a lavaliere or headset mic.

RF System Components Antenna Types The size of an antenna is directly related to the wavelength of the frequency to be received. The most common types used in wireless audio systems are 1/4- wave and 1/2-wave omni-directional antennas, and unidirectional antennas Antenna Combiner Device that receives and distributes RF signal from multiple systems. Uses an external antenna.

Hands On Suggested Readings

Advanced Mixing Technique
Work Flow Input List/Stage Plot Have a clear an detailed input list and stage plot Wire the stage as if you are reading a book. Left to Right Do things the same way every time! Be in charge and be assertive! Line Check Call out the channels as they are labeled in order on your console. Input Gain (Solo or PFL) Quick EQ appropriate for instrument or vocal Bring up fader for quick listen in the house You can worry about the house mix after the monitors are finished

Monitors If using wedge stage monitors try to encourage vocals only in the monitors. Reverb is a no-no also! Ask the talent to plug their ears if you need to ring out feedback. They will like you for this! Instruct your talent on the proper use of their microphone Less is more. The louder the monitor the louder the house mix will be. If using multiple in ear monitor mixes have call out each channel as you did in line check. Have the talent put their hands up if they want to hear a particular instrument. Have them lower their hand when they have enough level.

Troubleshooting Troubleshooting skills are learned over time 99.99% of the time it’s a very basic problem People often look beyond the root of the problem Start at the source and work towards the mixer. Verify signal flow. Start from the mixer and work towards speakers. Verify signal flow Check the patch on stage Check DI (pads, connected correctly, ground lifts) Check Phantom Power (does the source require phantom? Is the mic cable bad?) Check the mic line with a dynamic mic Make sure amps are all plugged in and turned on Unless it’s a show stopper, move on and finish line check. Troubleshoot when you have more time and people are not waiting

Multiple Zones Can be front fill, delay, under balcony, center cluster, feed to camera or another room. Zones can be fed from a matrix output, post fade-aux, mono send or sub group out. Adding delay to zone output can help with time alignment. Make sure the zone is not too loud

Scenarios Show #1: You are mixing an event featuring the CEO of the XYZ Widget Corporation Set up a show with a single lectern microphone and a CD player. The microphone requires phantom power. You are using a speaker system which requires a left and right feed from the console. The speaker system needs to be equalized using a 31 band graphic equalizer inserted across the left and right outputs. The person speaking from the lectern has requested a stage monitor so he can hear the music from a CD player. He would also like to hear his voice in the monitor. He has requested music be sent to the monitor post fader and his voice be sent pre fader. The stage monitor will need to be equalized using a 31 band graphic equalizer. Frequencies 315 Hz and 3.15 K are both feeding back in the stage monitor and you need to cut 6 dB of each freq via the graphic equalizer which has been assigned to the monitor send. The lectern microphone channel needs to have a HPF at 125 Hz This show will be saved to scene #5 on the console. Please name it XYZcorp

Scenarios Show #2: The “I need more cowbell” band is performing at Owens Set up a show featuring a small band with 2 direct guitar inputs, 2 vocal inputs and one cowbell microphone input. The band has requested 2 individual pre fader monitor mixes. You are mixing on a speaker system which requires a left, right and center cluster feed from the console. The left, right and center zones need to have 31 band graphic equalizers inserted across their outputs. Aux 4 will feed the center cluster with only vocals. The Aux should be post-fader The band has requested a plate reverb be used on their vocals. The reverb needs to have a decay of 2.4 seconds and a pre delay of 45ms. The reverb will return on stereo channel #1. Continued on next slide

Scenarios Show #2: The “I need more cowbell” band is performing at Owens Continued: The cowbell player has requested a hall reverb be used on the cowbell. The reverb needs to have a decay of 1.3 seconds and a pre delay time of 10ms. The reverb will return on stereo channel #2. Each vocal channel needs to be hi passed at 125Hz, have a 6dB cut at 315 Hz and a 4 dB cut at 1K. Please EQ the first vocal channel and then use copy paste functions for the remaining channels The guitar channels need to have compression applied. The ratio of compression will be 3:1 with a threshold of -10 and a release of 20ms. After setting up the first compressor, please use the copy and paste features for these dynamics. This show will be saved to scene # 25 on the console. Please name it cowbell.

Scenarios Show #3- Floyd’s Fish Market Grand Opening Event You are mixing audio for a huge corporate event featuring the owner of Floyd’s Fish Market. The Just for the Halibut Band is providing music for the cocktail reception. The event is being televised live by the Nothing Beats Cod network (NBC). The news media is expected to be in attendance as well. You are mixing on an audio system which consists of a left and right main speaker cluster, a set of front fill speakers, and a set of delay speakers. Each speaker zone will need a graphic equalizer inserted across its output. The band requires 4 individual pre-fader monitor mixes, each need to have a graphic equalizer. The media and video company each need to have their own aux feed as well.

Scenarios Show #3- Floyd’s Fish Market Grand Opening Event Aux/Output/Rack assignments are as follows: Mix 1 out 1 Aux 1 pre fade Mix 2 out 2 Aux 2 pre fade Mix 3 out 3 Aux 3 pre fade Mix 4 out 4 Aux 4 pre fade Front fill out 5 Aux 5 post fade Video out 11 Aux 11 post fade Media out Aux 12 post fade Delay out (mono Bus). Need 125’ delay time applied Left out 15 Right out 16 Reverb Plate FX 1 FX Return 1 Reverb Plate FX 2 FX Return 2

Scenarios Show #3- Floyd’s Fish Market Grand Opening Event Please label the band inputs as follows: Kick, Snare, Overhead, Bass, Accordion, Guitar, Vocal, Vocal Phantom power should be applied to every band input. Please assign the entire band to mute group #1. Please assign pink noise to the video and media outputs for them to verify signal. The pink noise should be sent at -18dB Using the mix on fader function please set the guitar channel to unity “0” in Mix #1 and Mix #3 Please save this to scene memory #4 and name it nbc. A comment should be made about the event in the scenes comment window.

Thank You!! Todd Mitchell Vice President Great Lakes Sound, Inc.
230 Arco Drive Toledo, Ohio 43607 Office

Live Sound 101.

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