Understanding Basic Signal Flow Lets get connected Input

Understanding Basic Signal Flow Lets get connected!

Input Sources • Microphone level approximately -60 d. Bu • Line level approximately +4 d. Bu • -10 d. BV Standard voltage reference level for consumer and some pro audio use (Tip: RCA (or phono) connectors are a good indicator of units operating at -10 d. BV levels. )

When you think of the sound for any given instrument or device. Think of the sound/signal flowing like streams, lakes, etc. The point is, anywhere in this chain, if the wrong connector is used, or a level setting is wrong, the loss of gain cannot be made up somewhere in the chain without a addition of noise

Balanced & unbalanced lines

Balanced Lines • Two conductors are driven equally and oppositely with respect to ground. (3 conductors = positive, negative, ground) • Balances lines are the preferred method (for hum free) interconnecting of sound systems using a shielded twisted pair wire. The principal behind balanced lines is that the signal is transmitted over one wire and received back on another wire. The shield does not carry any information, so it is free to function as a true shield for the plus and negative wire.

Balanced Lines • Mic cables are balanced lines. They use a gendered (male and female) XLR connector • XLR® is a registered trademark of ITTCannon - a manufacturer of connectors. The original model number series for Cannon's 3 -pin circular connectors - invented by them now an industry generic term. (you will still hear old rock n’ roll sound dogs say…”go plug that into the cannon jack”

• Balances lines are the preferred method (for hum free) interconnecting of sound systems using a shielded twisted pair wire. The principal behind balanced lines is that the signal is transmitted over one wire and received back on another wire. The shield does not carry any information, so it is free to function as a true shield for the plus and negative wire. • Because there is three conductors, there must be three points on the connector to carry the current.

RCA = unbalanced TS = 1/4” Tip Sleeve = unbalanced TRS = 1/4” Tip Ring Sleeve = balan XLR female panel mount = balanc XLR female cable = balanced

RCA Jack

• RCA jack (AKA phono jack) The Radio Corporation of America (RCA) originally developed this type of pin connector for internal chassis connections in radios and televisions during the '30 s. It was adopted at this same time for phonograph players hence the reference phono jack. Now the standard for use in line level consumer audio and project studio sound equipment, and most recently to interconnect composite video signals.

TS (tip sleeve) 1/4” Plug

• The TS (Tip Sleeve) or 1/4” or Phone Plug was originally invented for the telephone industry… picture a Erin Walton working as a telephone operator using the telephone patchbay “connecting” John Boy to the Drew Drop Inn. • This is not the recommended plug for high power-speaker connection. This is due to its limited power capabilities.

TRS (tip ring sleeve) 1/4” Plug

• Balances lines can also use a 1/4” type of connector. This is called a Tip/Ring/Sleeve or TRS • This is not a “guitar cable” • This is not wired the same as a stereo headphone jack. • Balanced lines are used to interconnect system equalizers, crossovers and other balanced equipment. • There is no electrical difference between XLR and TRS but we prefer the locking properties of the XLR.

TRS male XLR female

Unbalanced Lines • 2 conductors - center positive conductor is surrounded by a shield • An unbalanced line transmits the audio signal between one wire and ground. The circuit path is down the wire and back through the shield cable connected to ground. Ground is the return path; the circuit does not work without it.

Passive Direct Box • This is used to connect keyboards and other electronics that have a line/Instrument level out (typically a 1/4” unbalanced out) to low impedance mic level out • As a passive unit, the signal is as good as the transformer that is built within it. • Get one with a ground lift switch. • Generally, by going through a passive DI, (direct injection) you loss from 3 to 6 d. B of signal.

Passive Direct Box • 1/4 unbalanced in to XLR balanced out This is how to connect to your board • Great for keyboards & guitar preamps.

Active Direct Box • This is used to connect bass guitars and other electronics that have a line/Instrument level out (typically a 1/4” unbalanced out) to low impedance mic level out • Higher input impedance will help preserve upper harmonics • Better transformer - more highs - more lows • Get one with a ground lift switch. • No loss but needs a 9 volt battery or phantom power.

• Do not plug your electric guitar into a “normal” direct box • Its sounds brittle, crunchy…well…just bad.

Specialized Direct Boxes • There is an alteration of the sound caused by the frequency response of the guitar amp speaker and a microphone in front of that speaker. • Specialized Direct Boxes (D. I. ’s) are manufactured to reproduce this sound

Phantom Power ! What is it and why do I need it?

• Phantom power is a system of providing electrical power for condenser microphones (and some electronic pickup devices) from the sound mixer. The system is called phantom because the power is carried on standard microphone audio wiring in a way that is "invisible" to ordinary dynamic microphones. • Must use a balanced cable to deliver it to the stage

Lets look at some typical inputs to the console

VCR Wireless Receiver Cassette Linelevel Levelout Mic or Line Level with 1 : 1 Transformer Direct Box unbalanced to balanced Mic Note a “hot” mic is not necessarily indicative of a superior mic

Normalizing • In audio terms, normal or normalize is a zero state. This means: • Trim - off • Aux - off • Eq - zero • Hi Pass filter - zero • Pan - center • Assign - none • Fader down

Lets look at a typical channel strip

• Here is a closer look at the Trim Control

TRIM Control • Signals connected to the channel inputs could vary from extremely small to very large. TRIM sets the gain (volume level) of the channel input amplifier. Proper setting of the TRIM control is essential for good noise and headroom performance.

The Mic Preamp • This amplifier brings the very low signal level of a microphone (approximately -60 d. Bu) up to line level (approximately 0 d. Bu). Mic preamps often have their own volume control, called a trim control, to properly set the gain for a particular source. Setting the mic preamp gain correctly with the trim control is an essential step in establishing good noise and headroom for your mix.

TRIM Control Setup • Lets assume that the console is a “normalized” state • Engage the PFL button (Pre Fader Listen) which will put this channel to the LED display • With the fader down, you will see and not hear the input signal if your console has a metering section • Remember that after you adjust the EQ for this channel, you might have to re-adjust the TRIM. (if you add lows to the EQ…you have also added signal so you will have to adjust the TRIM down.

Here is a closer look at typical channels input connectors • Mic Level input A mic level signal (usually but not always coming from a microphone) is generally below -60 d. Bu.

• Balanced or unbalanced line inputs are used for line level inputs • line level A signal whose level falls between -10 d. Bu and +30 d. Bu. • Note - a balanced line level input can use an XLR jack - but it is not a mic level input

• This allow us to “insert” a modifying device (such as a compressor, FX unit, EQ etc) into this channel. • Insert points are typically after the Trim control but before the channels EQ, fader and Mute. • Inserts can also be found on Group Masters and Main outputs

Lets look at a typical unbalanced insert cable

• • TRS is inserted into the channel, group master etc Tip is out of the sending console Ring is return of the sending device Sleeve is the common ground to complete the unbalanced circuit TIP to device input TRS RING to device output

Unity Gain • VERY IMPORTANT: Unity gain is the point at which no level is added to or subtracted from the nominal signal. • If after setting the trim, you add 6 d. B of lows…you will then have to readjust (tweak) the trim to compensate. • Proper setting of the input level and output levels of all devices (FX units, compressors EQ etc) is important to the signal to noise ratio.

EQ, compressor, and crossover all have gain stages before it goes down a 100+ foot snake before it gets into the amplifier (the final gain stage) The point is, anywhere in this chain, if the wrong connector is used, or misuse of unity level setting, the loss of gain cannot be made up somewhere in the chain without a addition of noise

• The function of the amplifier is to amplify the audio signal that comes upstream from this device. • If part of that audio signal contains noise, that noise will also be amplified.

• A power amplifier level/volume/gain” controls are input sensitivity controls. (no matter how they are calibrated. ) They are not power controls. They have absolutely nothing to do with output power. They are sensitivity controls, i. e. , these controls determine exactly what input level will cause the amplifier to produce full power. Or, if you prefer, they determine just how sensitive the amplifier is. For example, they might be set such that an input level of +4 d. Bu causes full power, or such that an input level of +20 d. Bu causes full power, or whatever-input-level-your-system-may-require, causes full power. • They do not change the available output power. They only change the required input level to produce full output power.

• Soooo…you do not need your power amplifier level/volume/gain turned up all the way. Properly adjusted…you will also find your idle noise will disappears!

How do I set my amplifiers? • Play a source material indicative of the type of music program you use. (remember if playing a CD, there is no stage volume - factor this in to your level setting) • Set unity at the console and throughout the signal chain. • Start with the amplifier or amplifiers off. • Slowly bring them up to the volume you need in this room. (then add a scooch) • Your signal to noise ratio will be incredible!

Connecting the amp to speakers (portable) • Neutrik NLFC is the recommended connector for speaker connection. • High Current • Locking • No exposed connectors - no possibility of shorting

• This series of professional speaker and amplifier connectors is recognized as the industry standard. The Speakon® product line now comes in 2, 4, and 8 contact versions. • This connection system offers the "quick lock" locking system and inserts on it's cable ends. The inserts feature solderless connections using screw type terminals with a captivated pressure plate. No special tools are required making these connectors 100% field repairable.

Connecting the amp to speakers (permanent) • The required size (or gauge) of the conductors depends on three factors: (1) the load impedance of the speaker (2) the length of cable required (3) the amount of power loss that can be tolerated.

• Keep speaker wire length to a minimum. (In large installs…where there is a large central cluster of speakers, the amp racks are mounted above the speakers - The amps are then remote configured, controlled and monitored via a computer application at the F. O. H. such as Crown IQ for Windows) • 12 gauge conductor size is typical - the outer jacket is not indicative of the size of conductor

• Here is a closer look at the AUX Send section

AUX SENDS • This allows the operator to tap off the channel signal to an aux send bus. This aux send bus then can be routed auxiliary devices. • Aux sends are generally used to provide mixes for stage monitors, effects units, and recording devices. • Aux send settings do not directly affect the signal routed to the main and submix buses.

…to pre or not to pre…. . . that is the question. . . • There are two types of basic aux sends. . . Pre EQ/Pre Fader and Post EQ/Post Fader • Consoles will have a combination of these choices

Pre Fader/Pre EQ Aux Send • Pre EQ means the aux send is tapped before (Pre) the channel strip EQ. You can change the EQ on the channel and it will not effect the tone of this send. • Pre Fader indicates the aux send is tapped before that channels fader. You can raise or lower the fader and it will not effect the volume of the this send • Pre Fader/pre EQ aux sends are usually used to feed stage monitors. This helps provide a stable tone and volume environment to the stage performer

Question • The band is cooking along on a real aggressive song. Everything is sounding great…and here comes the guitar solo. • When you bring up the guitar channel fader, the whole band has their hair parted back. What just happened?

Question The guitar channel fader was wrongly set to Post Fader/post EQ and not to the correct Pre Fader/Pre EQ.

Post Fader/Post EQ Aux Send • Post EQ means the aux send is tapped after (Post) the channel strip EQ. You can change the EQ on the channel and it will effect the tone of this send. • Post Fader indicates the aux send is tapped after that channels fader. You can raise or lower the fader and it will effect the volume of the this send • Post Fader/Post EQ aux sends are usually used for effects or recording sends.

Question • You have a performer singing to a cassette track. This track is going to the Mains (for the audience) as well as monitors (for the performer). This particular track has a 37 second fade out but you must fade it out 7 seconds. Do you choose Pre or Post fade? Is that your final answer?

• Here is a closer look at the EQ control

• The channel EQ is designed modify (if needed) augment or remove the frequency response of that channel’s input. • Low…Mid. . . Hi…fixed center…sweep…parametric… shelf…hi-pass…are types of EQ. • Low cut can be fixed or adjustable

• Here is a closer look at the ASSIGN section

• You should not force or push system beyond the parameters of your system such as amplifier power, speaker frequency response and room acoustics. • If you have a system that cannot reproduce 25 hz (really low - bass), adding at the EQ will only injure your system.

• Keep in your mind. . . the mix • do I really need to add that much low end to the keyboards…it will only mask & muddy the electric bass • If I have the Highs on all the channels up…there is not a difference in the sound palette. • You can mix with EQ to make things heard, not just volume!

• This sections routes the source to the Group/Buss or Main Mix faders. • By adjusting the PAN control, source material can be directed to where you want

What's a bus (or group) and why do I want to get on it?

• 8 Buss master section

• Lets add 8 channels for drums #1 Kick #2 Snare #3 Hi-Hat #4 Tom 1 #5 Tom 2 #6 Floor Tom #7 OH #8 OH

Now lets assign all the drums to group master #1 • After setting the individuals faders, you now can control this group of assigned faders at the group master fader #1.

• You can also insert compressor and gates on the kick, snare, etc individual channel. • Then you can also insert a compressor on the group master 7 that is keyed by the lead vocal.

• Lets add 6 channels for worship team #9 Nic #10 Chris #11 Pete #12 Mary #13 Sylvia #14 Laura

Lets assign the worship team to group master #7 • After setting the individuals faders, you now can control this group of assigned faders at the group master fader #7. • Then you can also insert a compressor on the group master that is keyed by the lead vocal.

Here is one example of group master assignments Drums/bass Keys Guitars Brass Strings Choir Team Lead Vocal

Lets talk about Ducking (or side chaining)

• You can insert 8 compressor into each group channel insert. • These can controlled by the lead vocal by “telling” compressor 1 -7 to “look” for the “key”…compressor 8 - the lead vocal. • When the lead vocal sings…it sends a signal to compressor 1 -7 telling them to take the volume down of each of the sidechained compressor ‘automatically” • Properly set, this technique insures a great mix especially when you are mixing many channels.

• Enrique sings background on some songs and other songs lead. By reassigning his individual channels pan control from hard left (group master 7 background vocals) and panning it hard right (group master 8 lead vocal) and doing the opposite to Sams individual channel, who now be singing background, the compressor key priority is easily changed.

• Pastors wireless lav or podium mic can have an individual channel inserted EQ and compressor. • These can be assigned directly to the Main Mix output. • You can easily mute group masters 1 -8 when the pastor is talking. • Source material such as VCR audio, cassette and CD can also be routed directly to the Main Mix output