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