what is impedance? impedance (z) is the resistance of a circuit to alternating current, such as an...

Hi z = Line levelHi z = Line level Low z = Mic LevelLow z = Mic Level Direct Box changes impedence Direct Box changes impedence

from line level to mic levelfrom line level to mic level

High / Low ImpedanceHigh / Low Impedance

A high impedance A high impedance circuit tends to have circuit tends to have high voltage and low high voltage and low currentcurrent

A low impedance circuit A low impedance circuit tends to have relatively tends to have relatively low voltage and high low voltage and high currentcurrent

Connecting DevicesConnecting Devices

I'M CONNECTING TWO AUDIO I'M CONNECTING TWO AUDIO DEVICES. IS IT IMPORTANT TO DEVICES. IS IT IMPORTANT TO MATCH THEIR IMPEDANCES? MATCH THEIR IMPEDANCES? WHAT HAPPENS IF I DON'T?WHAT HAPPENS IF I DON'T?

Connecting DevicesConnecting Devices When you connect two devices, one is the When you connect two devices, one is the

source and one is the load.source and one is the load. The source is the device that puts out a The source is the device that puts out a

signal.signal. The load is the device you are feeding the The load is the device you are feeding the

signal into.signal into. The source has a certain output The source has a certain output

impedance, and the load has a certain impedance, and the load has a certain input impedance.input impedance.

It’s important to match the output It’s important to match the output impedance of the source to the input impedance of the source to the input impedance of the loadimpedance of the load

Matching ImpedanceMatching Impedance

If the source impedance equals If the source impedance equals the load impedance, this is called the load impedance, this is called "matching" impedances."matching" impedances.

It results in maximum POWER It results in maximum POWER transfer from the source to the transfer from the source to the load.load.

low-Z source to a high-Z low-Z source to a high-Z loadload

Suppose the source is low Z and the load is Suppose the source is low Z and the load is high Zhigh Z

There is no distortion or frequency-response There is no distortion or frequency-response change caused by this connection.change caused by this connection.

When you plug a low-Z source (microphone) When you plug a low-Z source (microphone) into a high-Z input you get a weak signal. into a high-Z input you get a weak signal. That's because a high-Z input is designed to That's because a high-Z input is designed to receive a relatively high voltage from a high-receive a relatively high voltage from a high-Z mic or instrument, and so the input is Z mic or instrument, and so the input is designed to have low gain. So you don't get designed to have low gain. So you don't get much signal amplification.much signal amplification.

high-Z source to a low-Z high-Z source to a low-Z loadload

If you connect a high-Z source to If you connect a high-Z source to a low-Z load, you might get a low-Z load, you might get distortion or altered responsedistortion or altered response

For example, suppose you For example, suppose you connect an electric bass guitar (a connect an electric bass guitar (a high-Z device) into an XLR-type high-Z device) into an XLR-type mic input (a low-Z load). The low mic input (a low-Z load). The low frequencies in the signal will roll frequencies in the signal will roll off, so the bass will sound thin.off, so the bass will sound thin.

high-Z source to a low-Z high-Z source to a low-Z loadload

We want the bass guitar to be We want the bass guitar to be loaded by a high impedance, and loaded by a high impedance, and we want the mic input to be fed we want the mic input to be fed by a low-impedance signal.by a low-impedance signal.

Impedance-matching Impedance-matching adapteradapter

Active direct boxActive direct box

Low z – High z micsLow z – High z mics Most mics are low Z, and all mics with Most mics are low Z, and all mics with

XLR (3-pin) connectors are low Z.XLR (3-pin) connectors are low Z. A A low-Zlow-Z mic can be used with mic can be used with

hundreds of feet of cable without hundreds of feet of cable without picking up hum or losing high picking up hum or losing high frequencies.frequencies.

A A high-Zhigh-Z mic will lose highs and pick mic will lose highs and pick up hum if the cable exceeds about 10 up hum if the cable exceeds about 10 feetfeet

If your mixer has XLR inputs, they are If your mixer has XLR inputs, they are low-Z balanced.low-Z balanced.

Balanced and Balanced and UnbalancedUnbalanced

Balanced connectionsBalanced connections

A ¼” A ¼” balancedbalanced connection uses connection uses three wiresthree wires

Tip Tip Signal + (PositiveSignal + (Positive)) Ring Ring Signal - (Negative)Signal - (Negative) Sleeve Sleeve (Ground )(Ground ) TRSTRS

Balanced connectionsBalanced connections

An XLR An XLR balancedbalanced connection connection uses three wiresuses three wires

Pin 1 Pin 1 (Ground )(Ground ) Pin 2Pin 2 + (Positive + (Positive)) Pin 3 Pin 3 - (Negative) - (Negative)

Female MaleFemale Male

Balanced connectionsBalanced connections

The balanced connection has the The balanced connection has the advantage that it rejects noise advantage that it rejects noise and interference that may be and interference that may be picked up on long cable runspicked up on long cable runs

Unbalanced Unbalanced

An An unbalanced unbalanced connection uses connection uses two cable wires two cable wires

SignalSignal GroundGround

Types of CablingTypes of Cabling ¼ unbalanced line/instrument cabling¼ unbalanced line/instrument cabling XLR balanced cable used for microphone XLR balanced cable used for microphone

and line level connectionsand line level connections RCA unbalanced line level/ phono RCA unbalanced line level/ phono

connectionsconnections Speaker cable, various gauges depending Speaker cable, various gauges depending

on the applicationon the application AC CablingAC Cabling Patch bays are not common in live soundPatch bays are not common in live sound Mutipins ( Snakes, outboard racks, Mutipins ( Snakes, outboard racks,

consoles )consoles ) Inserts ( Tip, Ring, Sleeve, unbalanced x 2 )Inserts ( Tip, Ring, Sleeve, unbalanced x 2 )

Insert CableInsert Cable

Insert CableInsert Cable

Pg. 294Pg. 294 Gives you an unbalanced input and Gives you an unbalanced input and

output from a tip ring sleeve output from a tip ring sleeve connector on the consoleconnector on the console

Eq’s, Compressors, Gates, Effects Eq’s, Compressors, Gates, Effects for a single channelfor a single channel

English an American consoles may English an American consoles may be wired differentlybe wired differently

If no signal is present flip input If no signal is present flip input and output on the device being and output on the device being insertedinserted

Speaker CablesSpeaker Cables

Can be used with ¼” , Banana Can be used with ¼” , Banana Plug or Speakon connectors.Plug or Speakon connectors.

¼” Speaker Connector¼” Speaker Connector

¼” Speaker Connector¼” Speaker Connector

Tip Positive +Tip Positive + Ring Negative –Ring Negative – Do not use for instruments may Do not use for instruments may

cause buzzcause buzz Vice Versa ( Do not use Vice Versa ( Do not use

Instrument cables to run speaker, Instrument cables to run speaker, may short amplifier, causing may short amplifier, causing failure or damage )failure or damage )

Banana PlugsBanana Plugs

2 conductor connector positive and negative2 conductor connector positive and negative Fit into binding terminals on amplifiersFit into binding terminals on amplifiers Tab is usually wired to the negative terminalTab is usually wired to the negative terminal Can be piggy backed, connected to each otherCan be piggy backed, connected to each other Recently outlawed in EuropeRecently outlawed in Europe

Binding PostsBinding Posts

Speakon ConnectorsSpeakon Connectors

Three different typesThree different types NL2 NL2 NL4 NL4 NL8NL8

Speakon ConnectorsSpeakon Connectors Industry StandardIndustry Standard NL2 ( Two Pin Connectors ) +1 -1NL2 ( Two Pin Connectors ) +1 -1 Used for Single Speaker ConnectionsUsed for Single Speaker Connections NL4 ( Four Pin Connectors ) +1 -1, NL4 ( Four Pin Connectors ) +1 -1,

+2 -2+2 -2 Used for two Speaker Connections Used for two Speaker Connections

( Bi-Amp)( Bi-Amp) NL8 ( Eight Pin Connectors ) +1 -1, NL8 ( Eight Pin Connectors ) +1 -1,

+2 -2, +3 -3, +4 -4+2 -2, +3 -3, +4 -4 Used for 3 or 4 way Speaker Used for 3 or 4 way Speaker

ConnectionsConnections

Speakon ConnectorsSpeakon Connectors

No universal wiring configurationNo universal wiring configuration Check amplifier specifications for Check amplifier specifications for

pin wiring configurationpin wiring configuration

NL 4 Speakon CouplerNL 4 Speakon Coupler

NL 8 Speakon CouplerNL 8 Speakon Coupler

AdaptorsAdaptors Adaptors are available for every Adaptors are available for every

possible applicationpossible application

M/XLR to ¼”M/XLR to ¼”

M/XLR to ¼”M/XLR to ¼”

M/XLR TurnaroundM/XLR Turnaround

Fem/XLR TurnaroundFem/XLR Turnaround

RCA AdaptorsRCA Adaptors RCA to ¼”RCA to ¼” ¼” to RCA¼” to RCA Fem RCA to Fem RCAFem RCA to Fem RCA

XLR Split and Y CableXLR Split and Y Cable

ACAC

Alternating currentAlternating current Standard circuits are 115 volt Standard circuits are 115 volt

15amp 60Hz15amp 60Hz 1 amp = approximately 100 watts1 amp = approximately 100 watts Rule of thumb Maximum amount of Rule of thumb Maximum amount of

power you can draw from one 15 power you can draw from one 15 amp circuit is approximately 1500 amp circuit is approximately 1500 wattswatts

Hubble to CamlockHubble to Camlock

Camlock, Twist Lock, U-Camlock, Twist Lock, U-GroundGround

30 amp Break out30 amp Break out

Stove Plug 40 ampsStove Plug 40 amps

IECIEC

Powered SpeakersPowered Speakers Effects outboard equipmentEffects outboard equipment Instrument ampsInstrument amps KeyboardsKeyboards ComputersComputers ConsolesConsoles International Electrotechnical International Electrotechnical

CommissionCommission

Cabling TipsCabling Tips Don’t buy cheap cableDon’t buy cheap cable Keep all cable runs tidyKeep all cable runs tidy Do not run cables through the Do not run cables through the

performance area performance area Keep ac cabling and audio lines separate Keep ac cabling and audio lines separate

whenever possible to reduce noisewhenever possible to reduce noise Try not to run ac lines and audio lines Try not to run ac lines and audio lines

parallel to each other to reduce noiseparallel to each other to reduce noise Leave mic cable slack by the stand or Leave mic cable slack by the stand or

instrumentinstrument Do not leave mic cabling slack at the snake Do not leave mic cabling slack at the snake

head or piled up on top of each otherhead or piled up on top of each other Leave speaker cable slack by the speakers Leave speaker cable slack by the speakers

not the amps not the amps

Cabling TipsCabling Tips Do not share ac power with lightingDo not share ac power with lighting Use the proper length cable for the Use the proper length cable for the

application whenever possibleapplication whenever possible Use Sub snakes whenever possible to Use Sub snakes whenever possible to

reduce clutterreduce clutter Use strain relief whenever possibleUse strain relief whenever possible Don’t tug on cablesDon’t tug on cables Wrap over underWrap over under Pack up and wrap cabling in the Pack up and wrap cabling in the

reverse order of running themreverse order of running them