HOW TO USE THIS GUIDE ON AUDIO CABLES

Table of Contents

Page 3

“How to choose the Right AudioCable” is divided into chapters eachof which describes a different type ofprofessional audio cable or relatedtopic. The guide initially describesthe Universal Attributes of audiocables — which define the real needsof the customers who will use them.

Then, the chapters are brokendown into the various cable func-tions (types):■ instrument cables (the primary

cables used to connect guitars,basses and keyboards to theiramplifiers or mixers)

■ speaker cables, connectingamplifiers to loudspeakers

■ microphone cables, connectingmicrophones to mixing consoles

■ patch cables, 100’s of “behind thescenes” short jumper cables toconnect all the various hardwarecomponents to each other

■ multipair audio cables (snakes),the audio superhighway betweenthe stage and the soundman

■ M.I.D.I. digital cables (AES/EBU andS/P-DIF), to hook up all the newdigital equipment

Although the chapters are arrangedby product type, they also discussthe proper connecting of equipmentfor:■ guitarists■ bassists■ keyboardists■ vocalists

The guide also describes variousinterface (typically black box) prod-ucts needed to run a bandstand:■ mic splitters and combiners■ line level balancing transformers■ direct boxes (D.I.s if you are British,

“direct injection”)■ Kwik Fixers, problem solvers for

fast-fixes when emergenciesoccur.

Another topic discussed is gettingsignals to a monitor system and/or arecording console during live perfor-mances.

We talk about a very ignored(really boring) product — the stan-dard A/C electrical extension cord, sonecessary to proper band hookupand sound.

A Message from the Captain ........................................... Page 2

How to use this guide on Audio Cables ...................... Page 3

Choosing the right Guitar Cables .............................Pages 4-7

Choosing the right Microphone Cables .............. Pages 8-10

A lot about Shielding ....................................................... Page 11

Choosing the right Speaker Cables ....................Pages 12-14

Choosing the right A/C Extension Cord .................... Page 15

Universal Attributes of Audio Cables ................ Pages 16-17

Choosing the right Snake ...................................... Pages 18-21

Choosing the right Patch Cables .........................Pages 22-23

A discussion about Digital Cables ...................... Pages 24-25

What to look for in Interface Boxes ............................. Page 26

A little historyPro Co Sound was founded in 1974 to build portablesound systems for touring musicians. There were nocompanies manufacturing cables then so, out of self-defense, we learned to build cables that our customerscould not break. From 1974 to 1979 we built a touringP.A. (public address) system a day for bands, over 1,500 ofthem. From 1979 to the present, we have helped over 10million musicians cable their bandstands, studios and yes,even their bedrooms and basements. In 1979, a friendsaid we should sell our unbreakable “Lifelines” to musi-cians. Now Pro Co cables sell in sixty countries and ingreat music stores everywhere. However, cabling theband was a hobby that got way out of hand. We buildover 8,500 different products for our customers everyyear, and not because we are thrilled about building thatmany products. It is simply that entertainers need thatmany cables and related interface products to get theirgear to do what they want it to do. We are, in essence,plumbers to the audio trades; we do whatever it takesto hook up the band.

Intermediate

Advanced

Beginner

Icons at the top of each page willhelp you to quickly find what cabletypes you are looking for in theguide. Each chapter will describe aparticular cable, tell about differentconstructions with their pros andcons, include a “Let’s get technical”section and a “So, what cable shouldI buy?” recommendation.

To simplify your selection process,there is a color code by skill level(advanced, intermediate and begin-ner) to help youdiscover the bestcables for your use,depending on yourpersonal level ofperformance, yourneeds, and yourpocketbook.

Be sure to watch forthe color-coding thatappears throughoutthe cable guide. Thecolor-coding identi-fies information andproducts for beginner,intermediate andadvanced performers.

CHOOSING THE RIGHT GUITAR CABLES

Page 4

A guitar cable is theprimary cable connectingan electric guitar’s outputto its amplifier’s input or tothe input on the first effectpedal in the musician’spedalboard. Guitar cables

are also used to hook basses to bassamps and keyboards to mixers. Thebroad category for these types ofcables is “instrument”.

Guitar cables are constructedusing single-conductor audio cable(also called coax) with an overallshield, terminated in 1/4" phone plugs.

This chapter provides a reallyquick way to select your next guitarcable, plus it provides lots of informa-tion for those of you who want toknow more about how your equip-ment should be connected.

The BenchmarkIt is really difficult to buy a reallyflexible, really reliable, really rugged,really quiet, really great-sounding,really good looking 10' guitar cablefor under 20 bucks.

The guitar cablesituationThere is a wide variety of guitarcables because there is a widevariety of guitarists. It is almostimpossible to get two guitariststo agree on what a truly great“sound” is. Even if they did, oneof them would change his/hermind by midnight.

In any case, to keep pacewith the needs of this widevariety of players, we buildeight different guitar cablesin a wide variety of lengths,each with different stan-dards for reliability, shield-ing, sonic quality, flexibility,appearance and price.

The primary guitar cable isthe most abused on stage(besides the lead singer’smicrophone cable). There-fore, it must be built to

withstand extremetrauma during perfor-mance. Also, in actswhere appearance iscritical, it also has tolook like a million bucks.

Although the patchcables used betweenthe effect pedals andbetween the last effectand the amplifier (orpre amp) need tosound good and bevery quiet, the stresson them is not assevere as the stresson the primary cable.Light duty patch cablescan be used herewithout much fear offailure. (Wait a minute.This is not a license to go out andbuy cheap molded cables for yourequipment).

Because of the placement of theoutput jack on some guitars, a rightangle plug may be needed, especially

if your output is on the face of yourguitar. Not all dealers carry rightangle-equipped cables so you mayhave to special order one if you need it.

Also, for those of you who want tochange from one instrument to

another quickly on stage, Pro Cobuilds two “silent plug” equippedcables, each with a mechanicalswitch on one end that allowsquick on-stage transfer from oneinstrument to another instrument,while preventing “popping” asyou change. (The tip on a regularplug hits ground as you plug and

unplug without turning downyour amplifier, and this

makes an irritating pop.)

The real worldproblems withguitar cablesGuitar cables have allsorts of potentialproblems. They arenoisy. They are stiff anddo not lie flat on stage(this alone is a huge

irritant to players). Manyguitar cables are unreliable

and/or intermittent.

“One of my problems is when themusician stomps his/her boot heel intothe cable 500 times an hour on stage.”

The Quick Way(for those of you with only 30 secondsto spend on this purchase decision)

Ask yourself:Do I only want an inexpensive 10’ guitar cable?

If so, your base price is ..................................... $5.00Do I want it to be reliable?

If so, add five bucks ......................................... $10.00Do I want it to be quiet, with no hum or buzz?

If so, add five bucks ......................................... $15.00Do I want it to be flexible?

If so, add five bucks ......................................... $20.00Do I want it to sound good?

If so, add five bucks ......................................... $25.00Do I want it to look great?

If so, add five bucks ......................................... $30.00Do I want it to last forever and be guaranteed,regardless of cause, event abuse?

If so, double the price .....................................$60.00

Page 5

One of the biggest problems iswhen the musician stomps his/herboot heel into the cable 500 times anhour on stage. Cables literally getdestroyed through use.

Then, when the gig or rehearsal isover, cables get wadded up and stuckin the back of the guitar amplifierbecause they will not fit in the guitarcase.

There are ways to wind cables sothey stay nice and round. The 55people on earth who do this correctlyhave cables that will last a lifetime.This section is for the rest of you.

performance”. The wire in your cablemust be flexible and sturdy. “Thin”is generally not as reliable as “thick”cable, and thin is generally not asflexible as thick (yet, “thick” can alsohide a multitude of “cheap”).

The things that matter most inguitar cable construction are strength,flexibility, sonics, shielding andappearance.

Strength in a guitar cable’s wireis derived from the size (gauge) ofthe center conductor, the type andpercentage of coverage of shield, thethickness and material making upthe jacket and in the case of Pro Co’sGuardian brand of cables, Kevlar-in-the-core, to prevent cable stretchingand breaking — forever.

Flexibility in a wire is accomplishedwith the type of shield and its lay(pattern), flexible jacket compoundshelp, cable geometry helps (the way

Let’s talk technical about guitar cablesThere is a natural roll-off of high frequencies (they get “quieter”) in anyhigh impedance cable that is caused by cable capacitance.

This is also enabled by guitar pickups which have a very high outputimpedance. (There are active guitar pickups available, with line leveloutputs which correct this problem.)

Depending on you ears, you will begin to notice this roll-off around20' to 25'. This may or may not irritate you. If it does, use a shorter cable.

Capacitance is measured in picofarads per foot (pf/ft) and should be inthe mid 20’s to high 30’s for a satisfactory guitar cable. Over 40 pf/ft., thehigh end drops quicker. Under 20 pf/ft. the high end is great, but the cablebecomes extremely microphonic (mechanically noisy) as you movearound on stage.

Many cheap guitar plugs use steel center conductors for strength.Steel is a poor conductor for audio and can set up a magnetic field, whichseverely distorts the sound that goes through it.

We use only G & H Industries Show Saver brand plugs in all our guitarcables. Their center conductors are 12 gauge oxygen-free copper — thebest practical conductor for audio cable.

One of our competitors talks about how their cable improves yoursound. We don’t believe that for a minute, but even if a passive compo-nent like a cable could change your sound (oh, they change it all right bydesigning a capacitor into the wire, which does as much bad as good), wethink cables should take what came in one end and deliver it to the otherend with no change. If you want a different sound, that’s why the Gods ofthe audio industry made tone controls, equalizers and processing equip-ment. We believe in making all attempts to send signals to your equip-ment, unaltered, from one component to another — flawlessly.

Power Amp

Bass Guitar

The solutionsHere are the three most importantrules governing guitar cables:

Rule One for guitar cables is, “Buythe shortest cable you can live with”.

Rule Two for guitar cables is, “If itdoesn’t have a copper tip on theconnectors, don’t buy it.”

It is really difficult to buya really flexible, really

reliable, really rugged, reallyquiet, really

great-sounding, reallygood looking 10' guitar

cable for under 20 bucks.

That’s because the only 1/4" plugswe believe in are Show SaversTM

brand, 100% made in America by G & HIndustries in Centerville, Michigan.These are the best plugs made formusical instrument cables on theplanet and are the only 1/4'’ plugswe will use for our guitar cables.

Rule Three for guitar cables is to“find a cable that is as flexible andtangle-free as you need for your

Pre Amp

Power Amp

Pro Co Rat

Guitar

Page 6

it all fits together), thethickness of the outer jacket(the bigger the better) andthe number of strands in thecenter conductor.

With good plugs and goodwire and good soldering and

a good mechanical strain relief, wegenerally get a good cable.

Appearance is in the eye of thebeholder and the need for an attrac-tive, or flat-out exotic cable dependson personal preference and thevisual aspects of the performance.We think cables should at least looklike they were worth what you paidfor them.

Guitar cables carry minusculesignals that must be kept away fromnoisy light dimmers and audiofrequency interference that can jumpinto a cable’s signal path at any time.The cable’s shield helps to preventthis. Braided shields work betterthan spiral shields, but they tend to

saw themselves in two when youstomp your boot heel into themnight after night. Shielding is soimportant that there is an entirechapter devoted to it in this guide.

CHOOSING THE RIGHT GUITAR CABLES

Finally we need to talk about“sonics”, how our cable sounds. Abeginning guitarist who cannot yettune his/her guitar on the fly, doesnot need to have a real good cable.Anything will do, as long as it worksand is relatively quiet (lets in littlehum, buzz or crackle).

We can now put all this together

So, what kind of guitar cable do I need?Pro Co Brands:

Advanced Defender $57.50 (also available withright angle plug)

Sir Tweed $57.50 (also available withright angle plug)

Black Jack $57.50

Excalibur $40.18

Intermediate Line Cable $21.35 (also available withright angle plug)

Starguard $20.95 (equipped withSilent Plug)

Silent Knight $15.73 (equipped withSilent Plug)

Beginner Excellines $13.10 (also available withright angle plug)

so you can start making decisionsabout your next guitar cable purchase:

Since we said earlier that a reallygood 10' guitar cable is going to costyou $20 or more and say you want tobuy one for $10, what would youwant us to leave out to get the cabledown from $20 to $10?■ We can make the cable shorter.

How about 3 inches?■ We can get rid of some of the

shielding and add lots of buzz.■ We can extrude a thinner jacket

on the cable, reducing reliabilityand flexibility.

■ We can put less copper in thecenter conductor, reducing thecable’s reliability.

■ We can add clay to the jacket,replacing some of the exoticcompounds we have designed toimprove flexibility, sound andlong flex life. It will look the same,but for a lot shorter period oftime.

■ We can use plugs which are sturdybut change your sound.

A final thought. Warrantees andwell-built products often havenothing to do with each other.Cheap cable manufacturers put“lifetime” warrantees on poorly builtcables, hoping you will just throwthem away as they break. Or worseyet, do not put their company’s nameon the wire jacket, so that, when youneed to use the warranty, you cannotdetermine who built the product orwhere you got it. That does not helpmuch when it breaks during the bestsolo of your life or the best take ofthe day. Buy the good stuff. Tenyears from now, when you get boredwith your cable, then throw it awayand buy another Pro Co cable for thenext ten years of boring absolutereliability.

To find out what really matters toyou, take the following test. Whenyou are through, add up the pointsyou have scored then decide whichcable is right for you.

Appearance is in the eye ofthe beholder and the needfor an attractive, or flat-out

exotic cable depends onpersonal preference and thevisual aspects of the perfor-

mance.

How to choose the right guitar cable for you

Page 7

Circle the right fit for you

FlexibilityDoesn’t matter much to me 1 2 3 4 5 6 7 8 9 10 My cable must lie down flat and

follow me everywhere

ReliabilityI don’t abuse my cables 1 2 3 4 5 6 7 8 9 10 My cables must be bulletproof.

I stomp on it with my boot heel500 times an hour

SonicsI can’t hear the difference 1 2 3 4 5 6 7 8 9 10 I want to hear the natural sound of

my guitar, with no change in tonefrom my cables

ShieldingA little noise is OK with me 1 2 3 4 5 6 7 8 9 10 I want a dead quiet rig — no noise,

just my music

AppearanceAll I want is a sturdy cable that works 1 2 3 4 5 6 7 8 9 10 A professional, even flashy look is

important to my show

Attributes Add up your points below

Flexibility

Reliability

Sonics

Shielding

Appearance

Total Points =

Suppose your points are dollars. Which cable is best for your use?

Pro Co’s Instrument Cables

10’ MSRP 10’ MSRP

Black Jack ........................................................................... $57.50 Lifelines ............................................................................... $21.35

Defender ............................................................................ $57.50 Star Guards ........................................................................ $20.95

Sir Tweed ............................................................................ $57.50 Silent Knight ..................................................................... $15.23

Excalibur ............................................................................. $40.18 Excellines ............................................................................ $13.10

CHOOSING THE RIGHT MICROPHONE CABLESIn this chapter, you will learnabout microphone cable

construction and selectionwith recommended products

for various types of use. Wewill cover:

■ XLR connectors■ Balanced and unbalanced

connections■ Wiring of the different types of

microphones■ The right wire for microphone

cables, including shielding■ A short section for vocalists only

BenchmarkIt is really difficult to buy a reallyflexible, really reliable, really quiet,really good-sound, really good-looking 25' microphone cable forunder 30 bucks.

The mic cable situationMicrophone cables connect micro-phones to mixers (desk, consoles,

whatever you want to call them).In pro audio, microphones are lowimpedance (Lo-Z) and are terminatedin 3-pin XLR connectors.Pin 1 (X)ternal ShieldPin 2 (L)ive Hot (+)Pin 3 (R)eturn Cold ( - )

Another typical configuration isemerging which includes an XLRfemale (the output of all professionalmicrophones is a 3-pin XLR male)

Lo-Z Microphone cables can alsobe wired “unbalanced” and “Hi-Z”(high impedance) microphones areavailable, for high impedance soundsystems (didn’t take long to getconfusing, did it?).

Hi-Z cables allow the user to pluga Hi-Z microphone directly into theinput of, say, a guitar amp or theinput of a Hi-Z mixer.

connector to a 3-pin mini male(1/8" or 3.5mm) connector for

inputs to laptop computersand other devices wherespace is at a premium.

Most professional mixer’smicrophone inputs aredesigned with “balanced”circuits to help decrease or

eliminate noise and un-wanted radio frequencyinterference (RFI). Theunderstanding ofbalanced circuits andlow-impedance iscomplicated and isaddressed in Pro Co’swhite papers onmicrophone cables,which can be foundat our website:www.procosound.com.

It is really difficult to buy areally flexible, really reliable,

really quiet, really good-sound, really good-looking

25' microphone cable forunder 30 bucks.

Unbalancing a balanced micro-phone by using an unbalanced cableallows it to sometimes be used in theinput of a Hi-Z mixer. This does notalways work, depending on the inputimpedance of the mixer. When thisdoes not work, a Lo-Z to Hi-Z trans-former must be placed in line at theend of a standard Lo-Z mic cable.These commercially available trans-formers make the proper changefrom XLR to 1/4" for you.

1 2

3

Lo-Z Microphone Cable

12

3

XLR Female XLR Male

1 2

3

Lo-Z Unbalanced Microphone Cable

XLR Female 1/4" Phone Plug

1 2

3

Hi-Z Microphone Cable

XLR Female 1/4" Phone Plug

Lo-Z to Hi-Z Transformer

1 2

3

“One of my problems is makingsure the minister does not trip

on a microphone cable.”

Page 9

The real world problemswith microphone cablesThe quality and type of cablesneeded depend on the application:

“Cannot fail” situations:■ Cables used for live concerts,

amateur and professional, TV/Radio recording and broadcast,ENG (electronic news gathering),recording studios and churchesand all other situations whereperfection is demanded andfailure and noise are not options.

Brutal environments:■ Workhorse cables for touring

bands and hard use situationssuch as A/V (audio visual) rental.

Normal duty use:■ Light-duty church and

auditorium use, weekend bandsand rehearsal halls.

Light duty/little use■ Beginner use and “thrown-in-

with-the-deal” while buying themicrophone, that work enoughto get you started.

Mission Impossible:■ Lead signers in rock bands who

tend to try to destroy mic cables, areal life test of durability.

Note: With the addition of Kevlarto our Ameriquad and Merlin brandsof microphone cable assemblies (1998),these cables can be used in situationswhere everything else breaks.

The Solutions

About Microphone WireMicrophone wire consists of atwisted pair of copper conductors(typically 22 - 24 AWG — AmericanWire Gauge). These conductors arecovered with one of three types ofshielding: braided, spiral (also called“serve” shield), and foil shieldingwhich includes a drain wire. Foilshields work great in snakes, butprove to be unreliable in cablesdesigned for portable use.

Braided shield is best for mic cablesand spiral is a little more flexible andless expensive than braid.

Microphone ConnectorsXLR audio connectors come in avariety of contact materials, gold,silver and tin. The trade generallylikes silver for sound, gold for tarnish-free contacts and tin for price.

Let’s talk technicalabout mic cablesTry at all costs to avoid Hi-Z andLo-Z unbalanced mics. You arenot doing your performances anyfavors by using these products,regardless of price.

4-conductor (quad) mic cableis so dramatic in its noise reduc-tion that the only reason not touse quad mic cables everywherein your sound system is price.

As sound system operatorsfind out how much quad micwire reduces noise compared towell-designed and built twoconductor assemblies, they areturning to the wire as a logicalstep up in their system perfor-mance.

A friend of Pro Co’s, whooperates several county fair P.A.systems, working in the abso-lutely worst conditions imagin-able, has found that with the useof Pro Co’s Ameriquad wire tohelp eliminate “hiss” from hissystems, that the artists, oftentimes, are unable to detect thatthe sound system is “on”. They areso used to listening to hiss as anindicator that the equipment isworking that this unsettles themgreatly. From an engineeringstandpoint all we can say is, “Weget it right and they still com-plain”. Good grief!

This gets you a cheaper price onthe original unit and lots of head-aches hooking it up, night after night.

Aside from these occasionalcompatibility problems and types ofconnector contact finishes, most XLRconnectors will work just fine formost situations. We suggestbuyng cables which use Neutrik orAmphenol (the original ITT-Canon)connectors for best results.

There are about four good suppliersof XLR connectors on the planet and20 or so copy houses, which wreckhavoc on the trade, since they looklike industry standard connectors,but are not properly dimensioned.

Microphone cables, unlike guitarcables, use a female connector on oneend and a male connector on theother. This enables microphone cablesto be daisy-chained, hooked end toend, to increase length when necessary.

This requires a very narrow toler-ance for size and pin locations in theconnectors, to ensure that the femaleXLR (the one with the lockingmechanism) will lock and unlockwhen mated to its male counterpart.

Complicating these problems isone manufacturer in America whouses English measurements, a lot oforiental copiers who have approxi-mated the English measurementwith metric measurements, and themanufacturers who are not copiersand make great, “to spec” connectorsusing metric measurements.

Yup! You guessed it. There arecompatibility problems. Furthermore,there are some budget mindedequipment manufacturers who willuse oriental knockoffs in their backpanels, exacerbating the problem.

With the addition of Kevlarto our Ameriquad and Mer-

lin brands of microphonecable assemblies (1998),

these cables can be used insituations where everything

else breaks.

Page 10

CHOOSING THE RIGHT MICROPHONE CABLESSolutionsMost professional Lo-Z microphoneoutputs can easily be run up to 500feet. However, Hi-Z microphoneshave the same roll off problems thatguitar cables have and their lengthsshould be limited to 20' or less to avoidhigh frequency attenuation.

Microphone wire comes in a widevariety of diameters. Lavalier micsrequire tiny, yet sturdy cables. Nature-sound recording enthusiasts needsmall cables that will roll up into thecompartment provided in their Nagratape recorders to conserve space.Most microphone cables are aboutthe diameter of a normal pencil (1/4")to provide the user with a reliable cable.

We have found that to present anaudience with totally no-hum, no-buzz, no-crackle sound systemsrequires the use of quad (4-conductor)microphone cables.

In situations such as TV studioswith huge hum fields created by TVcameras and county fairs with lots ofstray radio frequency interference, 4-conductor mic cables can lower humand noise up to 20 dB (20 decibels —a lot) comparted to any two-conductor

microphone cable.Why does quad mic cable work?

So, what kind of mic cables do I need:Pro Co Brand 25’ Model # MSRP

Advanced Merlin ME-25 $77.50

Ameriquad AQ-25 $50.00

If you are an advanced play, look for a cable with:a braided shield, 95% or better shield coverage, goldcontacts, Kevlar reinforced core and 4 conductor cable.

Intermediate Mastermike M-25 $38.75

If you are an intermediate player, look for a cable with:a braided shield, 90% + shield coverage and silver/goldcontacts.

Beginner Excellines EXM-25 $28.70

If you are a beginning player, look for a cable with:a spiral shield, 70-90% shield coverage and silver/tin contacts.

Here’s the easiest way to think about it.Balanced mic cables are quieter thanunbalanced mic cables because 1/2of the signal travels on one of thetwo conductors and they tend tocancel out extraneous signals that

XLR Female to XLR Male Balanced Lo-Z Microphone Cable

XLR Female to Balanced Mini (1/8”) Male Microphone Cable

XLR Female to Unbalanced 1/4” Phone Plug,either Unbalanced Lo-Z or Hi-Z depending on how it is wired

For vocalist only: spendingmore on a great vocal micthat sounds like you, and

picks up your tone and youremotions, is something youowe yourself and your audi-

ence.

jump on both conductors. The tighterthe two conductors are twistedtogether, and the shorter their twist,the better the wire is at canceling outnoise. When two pairs of conducts aretwisted together (four conductorstotal), this makes the conductorsmuch more tightly wound, and,subsequently, ten times better atdefending against interference.

25’ Lo-Z microphone cables run inprice from about $15 to $75, depend-ing upon the connectors and wireused. The watertight cables used to filmthe “Titanic” are worlds apart from the“thrown-in-with-the-mic” cables givenaway by retailers to “clinch the deal”.

For vocalists onlyYour microphone is your instrument.There are wireless mics now thatsound nearly as good as mics withcables and allow you complete free-dom of motion on stage. That is,when they cost $3,000 each.

For the rest of you, spending moreon a great vocal mic that sounds likeyou, and picks up your tone and youremotions, is something you oweyourself and your audience. It alsohas to have great feedback rejectionif you are using a monitor system.

If you have spent the money to getyourself a great microphone, get agreat cable to go with it, one thattransmits your sound and your emo-tions to your audience, without noiseand without adding any tone of itsown. We build cables that can to that.They are called “Merlin”, and they aretruly magicians at work.

Page 11

A LOT ABOUT SHIELDINGIn this chapter, you will learn waymore about shielding than you need.We’ll start with what shielding does.Then we will discuss what makes oneshield better than another and talkabout the characteristics of each andwhich is “best”.

What does the shield do?The copper shield of a coaxial cableacts as the return conductor for thesignal current and as a barrier toprevent interference from reachingthe “hot” center conductor. Unwantedtypes of interference encounteredand blocked with varying degrees ofsuccess by cable shielding includeradio frequency (RFI) (CB and AMradio), electromagnetic (EMI) (powertransformers) and electrostatic (ESI)(SCR dimmers, relays, fluorescentlights).

What makes one shieldbetter than another?To be most effective the cable shieldis tied to a ground — usually a metalamplifier or mixer chassis that is inturn grounded to the AC power line.Cable shielding effectiveness againsthigh-frequency interference fields isaccomplished by minimizing thetransfer impedance of the shield.At frequencies below 100 kHz, thetransfer impedance is equal to theDC resistance — hence, more copperequals better shielding. Above 100kHzthe skin effect previously referred tocomes into play and increases thetransfer impedance, reducing theshielding effectiveness. Anotherimportant parameter to consider is theoptical coverage of the shield, whichis simply a percentage expressinghow complete the coverage of thecenter conductor by the shield is.

What are the characteristics ofthe three basic types of cableshields? Which is best?A braided shield is applied by braid-ing bunches of copper strands calledpicks around the insulated, electro-

Spiral Shield

Braided Shield

Foil Shield

statically shielded center conductor.The braided shield offers a numberof advantages. Its coverage can bevaried from less than 50% to nearly97% by changing the angle, thenumber of picks and the rate at whichthey are applied. It is very consistentin its coverage, and remains so as thecable is flexed and bent. This can be

crucial in shielding the signal frominterference caused by radio-fre-quency sources, which have veryshort wavelengths that can entervery small “holes” in the shield. ThisRF-shielding superiority is furtherenhanced by very low inductance,causing the braid to present a verylow transfer impedance to highfrequencies. This is very importantwhen the shield is supposed to beconducting interference harmlesslyto ground. Drawbacks of the braidshield include restricted flexibility,high manufacturing costs becauseof the relatively slow speed at whichthe shield-braiding machinery works,and the laborious “picking andpigtailing” operations requiredduring termination.

A serve shield, also know as aspiral-wrapped shield, is applied by

wrapping a flat layer of copperstrands around the center in asingle direction (either clockwise orcounter-clockwise). The serve shieldis very flexible, providing very littlerestriction to the “bendability” of thecable. Although its tensile strengthis much less than that of a braid,the serve’s superior flexibility oftenmakes it more reliable in “real-world”instrument applications. Tightlybraided shields can be literallyshredded by being kinked andpulled, as often happens in perfor-mance situations, while a spiral-wrapped serve shield will simplystretch without breaking down. Ofcourse, such treatment opens upgaps in the shield which can allowinterference to enter. The inductanceof the serve shield is also a liabilitywhen RFI is a problem; because itliterally is a coil of wire, it has atransfer impendance that rises withfrequency and is not as effective inshunting interference to ground asa braid. The serve shield is mosteffective at frequencies below 100kHz. From a cost viewpoint, the serverequires less copper, is much fasterand hence cheaper to manufacture,and is quicker and easier to terminatethan a braided shield. It also allows asmaller overall cable diameter, as it isonly composed of a single layer ofvery small (typically 36 AWG) strands.These characteristics make copperserve a very common choice foraudio cables.

The foil shield is composed of athin layer of mylar-backed aluminumfoil in contact with a copper drainwire used to termintate it. The foilshield/drain wire combination is verycheap, but it severely limits flexibilityand indeed breaks down underrepeated flexing. The advantage ofthe 100% coverage offered by foil islargely compromised by its hightransfer impedance (aluminum beinga poorer conductor of electricitythan copper), especially at lowfrequencies.

Page 12

Speaker cables hookaudio amplifiers tospeaker cabinets.

BenchmarkThe ideal speaker cable

has zero-length wire, with no resis-tance, no capacitance, no inductance,and no change in sound from ampli-fier to speaker.

The ideal speaker cable does notexist. In its place are literally dozens ofhi-fi speaker cable companies toutingthat their tech-babble-supportedcable is a lot better than those otherpseudo-voodoo-audio guys. Most ofthese companies know nothing aboutlive sound and stay out of our hair. Acouple of them have wandered intoour market, clouding the main issueswith lots of technical nonsense.

Speaker cable selection dependson the output connectors on yourpower amplifier and the inputconnectors on your speaker cabinet,which have been pre-determinedby their manufacturers.

Regardless of which connectorsyou need on either end, cable manu-facturers make cables with all thecombinations you will need. Yourresponsibility is to buy the absoluteshortest speaker cables you can usewith the absolute largest conductorsyou can afford.

The speaker cable situation:Because live performance hasacoustics (often rotten) to deal with— acoustics that you do not have inyour home hi-fi or home theatre,there are lots of problems to dealwith besides exotic cables. Webelieve that current needs copperand lots of it. More about this later.

At Pro Co we believe in two basicrules for speaker cables:■ Less is best. Buy the shortest

cable possible for the application.■ More is best. Buy the largest gauge

speaker cables you can afford(the smaller the gauge number,the bigger the wire. Go figure.)

CHOOSING THE RIGHT SPEAKER CABLESThe three basic types of connectorsused for speakers in live performance are:1/4" connectors (the same ones usedin your guitar’s output), dual bananaplugs (designed 50 years ago to connecttest leads to diagnostic equipment,many of which are too small orcheaply made in the orient and willnot hold together), and Neutrik

three standards. We suggest you useonly G & H Industries Show Savers 1/4" plugs and their Boss dual bananaplugs with all speaker cables needingthese connectors.

Speaker level is not the place tobuy cheap cables. If a speaker cableshorts out, the amplifier’s protectioncircuit will turn on (hopefully) duringperformance to protect the amplifierfrom damage. Also, (hopefully) theamp’s protection circuit will turn offafter the cable is replaced so theshow can go on.

Having intermittent signal atspeaker level because of faultycables is a very bad thing to havehappen to your audience.

Besides being reliable, speakercables need to be flexible. Flexibilitycomes from using more (smaller)stranding in the conductors of thewire. The smaller copper strandinghas to be drawn through smaller andplugs and new banana plugs and we

One of my problems is teaching techniciansthat “Current Needs Copper.”

Speakons, wonderful connec-torsdesigned specifically for speakerapplications. There are other methodsof connecting amplifiers to speakers(spade lugs, bare wire) but these threeconnectors, 1/4" phone plugs, dualbanana plugs and Speakons are the

The ideal speaker cable haszero-length wire, with no

resistance, no capacitance,no inductance, and nochange in sound fromamplifier to speaker.

Page 13

smaller dies, taking longer to manufac-turer than larger strands thus they costmore. Flexibility also is enhanced byusing fillers in the cable to make thewire round and easy to coil and uncoil.Using larger strands of copper and nofiller is cheaper, but creates handlingproblems that just aren’t worth the fewextra bucks difference.

The real world problemswith speaker cablesGetting back to current needscopper, there are two basic specifica-tions to discuss regarding speakercables:■ Loss of power in the wire as heat

(because of resistance).This loss of SPL (sound pressure

level) caused by different gaugesof speaker cables is basically

unnoticeable in live performance,yet loss of power is talked aboutall the time because it is an easyconcept to discuss.

■ What is more important todiscuss is damping factor, acomplex concept which mattersmore to your sound and is noteasy to discuss.

Mackie Designs, says, “Dampingfactor is a number that representsthe ratio of the impedance of theload (speaker) to the output imped-ance of the amplifier. In practicalterms, it is a measure of how well theamplifier can control the movementof a speaker’s cone. The greater thedamping factor, the better its abilityto control the cone’s movement. Alow damping factor (under 20) allowsa woofer to continue to move afterthe signal stops, resulting in anindistinct and mushy low frequencyresponse.

Once the damping factor increasesbeyond 200, the audible effects ofthe damping become vanishinglysmall.

Community Professional Loud-speakers’ Chuck McGregor continuesthe explanation:

“The main effect of damping in aloudspeaker is to reduce the SPLproduced by the loudspeaker’sdiaphragm moving because of its

Let’s get technical about speaker cables:Flexibility in speaker cables comes from using high strand count conduc-tors. Pro Co uses the highest standard strand count available in all itsspeaker cables to enhance flexibility. Underneath the outer jacket, thetwo (or four) conductors are twisted about each other. The length ofeach twist helps to determine the flexibility of the assembly.

In an emergency, if the connectors are compatible, a guitar cable canbe substituted for a speaker cable for a short period of time. It’s tiny centerconductor will cause great resistance compared to its larger shieldgauge, and will cause power loss and poor damping factor. It maycause damage to your power amp as well.

Conversely, if a guitar cable goes bad, never, never, never use a speakercable to replace it. The hum (the speaker cable has no shield) will be sobad that you will not be able to stand it. This will give you a real goodindication of why we need good shields in microphone, instrument anddigital cables.

Pro Co is heading, as quickly as possible, away from soldering as atermination technique. Solder is not a particularly good conductor andthe ability to make good quality solder joints is an art that takes manyyears to perfect (as least we spend that much time with our assemblersworking on improvement).

Two relatively new termination techniques have gained interest inaudio cables. The first is currently used in microphone cables and iscalled IDC (insulation displacement connector), and we have had excellentresults in the past five years with our Excellines mic cables usingthis construction.

The other is ultrasonic welding, a cold weld process where the plugterminal and the wire are scrubbed and compressed at the same time,literally bonding the brass terminals to the copper wires (brass is 70%copper) in under a second. All 8 gauge Pro Co cables are ultrasonicallywelded to their terminals.

Both techniques create solid connections (IDC connectors require asturdy strain relief ), take very little time for human beings to master,and sound better than their soldered counterparts.

Your responsibility is to buythe absolute shortest

speaker cables you can usewith the absolute largest

conductors you can afford.

own inertia after the signal stops. Thefrequency of the sound it produceswith this movement will be at theresonant frequency of the movingsystem. A common term for this is

“overhang”. In severe cases this cantranslate into “one note bass”. Yourbass guitar no longer sounds like youbass guitar; it sounds like the free airresonance of your speaker cabinet.Yuck.

The SolutionTo repeat this for the third time,“Current Needs Copper”. We makecables using wires with these gauges:16 ga., 14 ga., 13 ga., 12 ga., 11 ga., 10ga. and 8 ga.

Pro Co makes 8 gauge cable for allindustry standard connectors nor-mally used. However, G & H Industireshad to design new 1/4"

Page 14

CHOOSING THE RIGHT SPEAKER CABLESSo, what kind of speaker cable do I need?

Pro Co Brand 50’ Model # MSRP

Advanced Fat Max FM-50 $185.008 gauge

PowerPlus S12-50 $75.9512 gauge

Intermediate Excellines S14-50 $50.7814 gauge

Beginner Excellines S16-50 $37.7316 gauge

These prices are for 1/4” to 1/4” cables only. Dual bananascost about the same as the quarter inch products. NeutrikSpeakons are a few dollars more.

Here are the statistics, if you are interestedPounds of copper in 25’ of speaker cable (both conductors):Gauge Pounds of Copper

16 gauge 0.39 lbs.14 gauge 0.62 lbs.12 gauge 0.99 lbs10 gauge 1.53 lbs8 gauge 2.50 lbs

Length of cable that can be made with one pound of Copper:Gauge Length of Cable16 gauge 64.0’14 gauge 40.2’12 gauge 25.3’10 gauge 15.9’8 gauge 10.0’

Damping Factor at 8 ohms Damping Factor at 4 ohmsGauge 10’ 25’ 50’ 100’ 10’ 25’ 50’ 100’16 gauge 90 38 21 10 45 19 10 514 gauge 138 60 31 16 69 30 16 812 gauge 201 91 48 25 101 46 24 128 gauge 113 64 56 30

Damping factor must be 20 or above to optimize live performance. Damping factor over 200 will add no appreciableperformance to the system. Note: the damping factors noted above in red are acceptable for use at the stated lengthand impedance (in ohms), but they are in no way optimized for reduction in power loss.

Damping factor at the outputs of the amplifier must be added to the damping factor of the cables to arrive at thesystem damping factor (alas, there are also more factors to consider that just these to determine an optimum system,but this represents the lion’s share need to make a decision).

Gauge acceptability for run lengths are noted above in red. Pro Co’s recommendations are to use 16 gauge under25 feet, 12 gauge under 100 feet, and if you can afford it, use 8 gauge everywhere.

had to create methodsto allow us to fit the 8gauge Fat Max wire intoNeutrik Speakons. Also,because we know thatgetting as much DC

(direct current) resistance out of ourspeaker cables is best for you, we donot solder the 8 gauge cables. Weultrasonically weld our 8 gauge cableto its especially-designed terminals.This reduces DC resistance in thecables to an immeasurable number,and creates a cable worthy of a placeon any stage on earth.

Page 15

CHOOSING THE RIGHT A/C EXTENSION CORDSA/C electricalextension cordshook the powercords of musicalequipment towhatever A/Cpower source isavailable. The

power source may be theoutlets on the stage, your own“clean” power distributionsystem or a generator at outdoorconcerts.

BenchmarkNobody knows much about powercords, because they are an essentialpart of our lives. Most of the powercords we use on stage are too smalla gauge and are orange (ugly).

Pro Co is going to raise the bar onthis sorry benchmark, if (and it will)it takes 20 years to do it.

The situationElectrical extension cords are away of life for electronic musicians.Everything with a power cord or anoutboard power supply (wall wart)needs to end up in a power strip orA/C cord.

Since music stores do not yet sellthe proper A/C cords that musiciansneed, the musicians buy their audiocables at the music store, then go toHome Depot to buy their orange 25',16-gauge $4.99 economy-dealcables.

The ProblemsOur equipment on stage, especiallythe power amps, needs lots ofcurrent to operate properly. Guesswhat? Power cords are about asclose to speaker cables as it gets.

They have three conductors (onefor ground) instead of two. They aregenerally offered in 16 ga., 14 ga.,and 12 ga. versions in various lengthsfrom 3 feet to 100 feet.

They have the same problems asspeaker cables — resistance (powerlost into the cable). Remember, the

smaller the gauge, the more resis-tance it takes to get all the powerto your equipment.

Gang, this is a no-brainer. If youwant your equipment to work right,you need to give it all the power itneeds to do the job. That is why somany traveling acts take along theirown power distribution systems thatthey tie into a clean (hopefully) 220amp source in the club or whateverthe venue.

Nobody knows much aboutpower cords, because they are anessential part of our lives. Most

of the power cords we use onstage are too small a gauge and

are orange (ugly).

Regular Plug

Tru Link Plug

Power Block Plug

SolutionsShort of your own powerdistribution system, whichis expensive and a luxury,here are some solutions toyour power cable prob-lems.

Buy short 16- or 14-gauge cables for equip-ment like mixers and

processing gear. There is so littlecurrent use that gauge is insignificant.

For power amps, guitar and bassamps and powered mixers, use 12gauge cables, period.

For feeds from A/C outlets on thestage, use 12 gauge cables, period.

None of this guarantees you willget all the power you need to runyour stage, but it will certainly help.

Here’s the only sales pitchin the whole cable guidePro Co sells the first A/C cablesdesigned specifically for entertainers.They are called E-CordsTM brand andhave four redeeming factors:■ They are built to take the rigors of

the road; they are not whimpy.■ The are available in 16-, 14- and

12 gauges and several endconfigurations.

■ They are black. No orange cablesallowed.

■ They are priced the same asother manufacturers interiorproducts.

These are just now (2000) starting tobe sold at smart music stores every-where.

Electrical ExtensionCords, especially

designed for use in the

entertainmentindustries

Cool Locking Feature

UNIVERSAL ATTRIBUTES OF AUDIO CABLES

Page 16

ReliabilityIf your bedroom or your basement is your stage, you can tolerate some equipmentfailures. If your passion and livelihood depend on making live music in clubs, theaters,studios or arenas, you need the confidence that your equipment will get you reliablythrough the gig.

Cables, like all products, come in a wide variety of quality and prices. With cheapprices come cheap materials (bad for you) and cheap labor (good for you, if theworkmanship is good). With expensive cables come (we hope) great materials andexpensive labor (good for you if the workmanship is good and very efficiently done),plus with expensive cables you usually get some “hype” to justify the high price.

You may need only an inexpensive cable or you may need the best inthe business. As you grow from beginner to recording artist,the environment changes (and so does the moneyinvolved). With any change in environment, frombedroom to concert hall, your needs willchange over time.

As you change environments, reliabilitywill become more and more importantto you, as the cost you have to pay forit will become less and less important.

AppearanceMost professional audio cables are round and black. Some are whitewith blue stripes. Some wires look like old tweed amplifier coverings.

Understanding the difference between the cool look and theconstruction and function of a really well designed cable is almost impossiblewithout destroying the cable to get at the answer.

If the connectors on a cable look too fancy or delicate and look like they belong in your home stereo,they probably do. They probably do not belong hooking up a stage full of professional musical equipment.

Stage presence and appearance are crucial to performing groups. Cables can add or detract from theoverall visual effects.

Having clean, uncluttered stages is difficult at best, depending on the equipment and show involved.Keeping your cables basic black so they disappear or blend in with the set is another part of becoming aprofessional artist.

ShieldingMusicians face two types of noise problems.First of all they face mechanical handling noise, created on stage by

moving microphonic cables around on stage and/or by stamping your bootheel into the cable jacket 500 times an hour. As cables are moved and bent,the shield moves and can create noise in your system. Properly designedwire prevents this noise.

Secondly, interference — hum, buzz and crackle, caused by RFI (radiofrequency interference) and less obvious types of interference. Shieldingcannot solve all your noise problems for you, since your stage A/C (electricalpower) and P.A. system A/C grounding must be done correctly to completelyquiet the stage.

Nonetheless, keeping audio signals pure, without the noise, requires well-shielded cables. Otherwise, cables can make dandy radio antennas. Creatinga quiet cable that is still flexible requires tradeoffs in shield coverage, type ofshield and the overall reliability of the cable

Our challenge is to build you a cable that is quiet enough for your needs(and nerves) that is flexible enough for your use, that is strong enough foryour responsibilities.

Page 17

FlexibilityFlexibility and reliability are contradictory elements in cable design. To get bothflexibility and durability takes good engineering, the right materials and consis-tent manufacturing techniques.

Until the last few years, if we built flexible, lie-down-on-the-stage cables, wegave up reliability. New developments in jacket materials, plus wise choicesconcerning the type, percent of coverage and lay (shape) of the shield, plusmore choices available for the insulating (dialectric) materials used, allow us toget very flexible cables with very good shields that are very durable.

By adding Kevlar to the core as a strength member on our Guardian cables,reliability has become a non-issue.

If your cable lies down flat on stage and follows you throughout yourperformance, that’s great. If it does not, it will be an irritation and

inconvenience — always in your way and always in your mind.

SonicsThe more critical your ear becomes, as you progress inyour journey to becoming a respected player, the moreyou will be looking for “your sound”. Cables can changeyour sound. Some manufacturers promote this as a plus.We do not think that this is a plus. Pro Co believes thatyou need control over your instrument’s tone and thatcables should be only a neutral conduit. We believe thatwhat exactly left your instrument should exactly betransmitted to your amplifier, without changes in tone,volume or frequency and without sacrifice to yourpersonal musical flexibility.

Conductivity (for speaker cables only)Guitars and basses put out very small signals (measured in milliamps — a

few 1000ths of an amp). Power amps can put out nearly 20 amps intoyour speaker cable. In order for you to get loud, really tight, punchybass, so you can hear the tonality of your instrument crystal clear,

your speaker cables need lots of copper in their conductors. Allthat current from the power amp needs lots of copper to travelthrough to efficiently transport clean signals to your speakers.

The more copper in the speaker cables, the less resistance inthe wire. The more signal that gets to your speaker, the less youramp has to work for a given volume. Your rig works easier, sendsa cleaner sound to your speakers, improving its ability toduplicate the sound of your instrument dramatically.

CHOOSING THE RIGHT SNAKESnakes are the most compli-cated part of cabling the bandbecause of the large variety ofuser needs, wide variety of

options available to fulfillthose needs and the often

times astronomical costs involved ingetting everything to work correctly.

Not all acts need a snake. Snakes(multipair audio cables) becomea necessity when an act needs asoundman or soundwoman to mixtheir sound for live audiences.

Before we begin our discussionabout snakes, we have to describe theingredients in a Public Address system(aka a sound system or P.A. system).

Then we need give you the ques-tions you need to ask before buyingyour first snake.

A basic P.A. system consists of:■ Microphones, mic stands and mic

cables■ A mixer to plug the microphones

into, to control tone and volume.■ A power amplifier to amplify the

signal from the mixer■ Speakers and speaker cables

Larger P.A. systems include some orall of the following equipment:■ Microphones, mic stands and cables■ An FOH (front of house) mixing

console■ Effects and equalization (E.Q.)

usually in an effects rack■ The snake■ Lots of patch cables■ A monitor system with a

mixer, effects and E.Q.,power amps and speakers

■ Microphone splitters■ Direct Boxes■ Electronic crossovers, as

most larger P.A.s arebi- or tri-amped

■ FOH speakers andpower amps

■ Feeds to the recording truck■ Feeds to the satellite uplink

for live broadcasts.■ Lots of road cases

Sometimes the mixer and amplifierare combined into one unit called apowered mixer. These are wonderfulsystems for wedding bands andother small groups that do notneed a soundman.

However, when it is time to increasethe size and versatility of the soundsystem, it is time to unload thepowered mixer and buy a separatemixer and power amplifier.

they’re still a bargain). There areseveral top-quality national touringcompanies capable of providinggreat sound for any size audience.

We are ahead of ourselves, so let’sgo back to the start of the journey.

BenchmarkIt is really difficult to buy a flexible,reliable, rugged, easy to coil anduncoil long-lasting 100' 20-channelsnake for under $500.

The snake situationThe snake is the audio superhighwayneeded to make larger sound systemswork at all.

When the decision has been madeto add a soundman or soundwomanto the act, the next challenge a bandhas in cabling is how to buy the rightsnake.

Snakes are confusing at first,expensive and have lots of points toconsider before being purchased.Later on, snakes become reallyconfusing, really expensive and haveeven more things to consider. The

point of all thisis to nevermake the samemistake once.

Snakesallows us to

combine severalbalanced (microphone)

cables into one smallerdiameter multipair

cable, making setupand teardown muchfaster and easier,with less spaghettithan would other-wise be the case.

Page 18

The snake is the audio su-perhighway needed to make

larger sound systems workat all.

From this modest beginning,sound system size, complexity andcosts go straight up to and includingsystems that take three semi-trailersof equipment for big venue acts.

By the time P.A.’s have all this equip-ment, they are so expensive that theyare much cheaper to rent than own(at $20,000 a day and up to rent,

“One of my problems ismaking sure musiciansbuy the right snake thefirst time for their use.”

Page 19

Let’s talk technicalabout snakesEach individual pair of conductorsin a snake is 100% foil shieldedfor maximum protection. Thealuminum foil is attached to amylar tape which needs to be 3/4"wide to shield the entire bendradius of the cable, no matterhow “kinked up” the snakebecomes during setup.

Most manufacturers use 1/2"foil. This just isn’t good enoughto do the job right.

Snakes have to be CL2 firerated to meet national electricalcodes. Building flexible CL2 ratedflat-black-jacketed snake wire is atough job. Also, there are trade-offs in flexibility and reliabilityin a snake. We opt, always, forreliability first, and flexibilitysecond. Our goal is to buildreliable snakes for you that youwill not swear at during setup.

Pro Co makes two grades ofsnakes. RoadMASTER, for toughnight after night professional use,and StageMASTER, for once totwice a month use for weekendwarriors, church youth groupsand school presentations. Weuse the same wire so they soundthe same. The hardware, connec-tors, strain relief and cosmeticsare completely different.

The real-world problemswith snakesFirst of all, there are several questionsthat must be asked before thepurchase of a first snake:■ How many microphones and

instrument signals do I need tosend from the stage to the FOHmixing board? You also need toask yourself if you are going toneed more channels later on. Thatway you can decide whether it ispractical or not to buy a larger

channel count snake than youcurrently need. Include in yourthoughts that you may have toadd an additional sub mixer orbuy a new, larger mixer to accom-modate all those microphones.

■ How many returns do I need tosend back to the stage (as drivelines to get signal back from theFOH mixer? Drive lines are a fancyterm for the line level signalsreturned to the stage to “drive” asignal to the power amps fromthe mixer.

Special Note: Those of you withpowered mixers absolutely cannotsend speaker level signals back tothe stage through standard snakes.The wires are too small to accommo-date that amount of current neces-sary. Doing this will cause either thepower amp in your mixer or yourspeakers to blow up.

If you have a powered mixer, youneed a powered snake, one withspeaker lines built in. Nobodyrecommends the use of these forlong runs (over 50 feet). There is

What is a Snake?What is a Snake?1

1

2

PA Speaker

Stage Mics

Stage

Fan Out

Mixing Board

To Power Amplifiers

3

4

5

2

Signal ReturnTo Stage Box3

4

5

Always use speaker cables to connect your

power amp and your loud speakers. Use the largest gauge speaker cables you can to maximize speaker control and minimize power loss. DO NOT USE INSTRUMENT CABLES HERE.

The mixed signals return to the stage via

your snake’s return channels. These signals are usually audio inputs for P.A. amplifiers or stage monitor amps using XLR connectors or 1/4" phone plugs.

The return signal must go to your power

amplifier(s) on stage for them to ultimately be heard through your PA speakers. Use line (instrument) cables or microphone cables. DO NOT USE SPEAKER CABLES HERE.

A Convenient Audio SuperHighway

Your mixing board is connected to the snake

at the "fan out". The signals from your mics and instruments travel through the snake to your mixing board for you to mix them into the great sound you want your audience to hear.

Microphones are connected to the snake

at the "box end" located on the stage. Instruments travel through the snake using direct boxs to balance the signals, correct levels, and minimize noise and interference.

Page 20

AdvancedYou would probably purchase a custom designed snake

that allowed for at least one split to the monitor system,with or without isolation transformers and ground liftswitches (although Pro Co’s rack-mount mic splitters couldallow you to continue to use your old snake if it has enoughchannels). You would buy short sub-snakes to go from themics on stage to the splitter and short mic cables to gofrom the splitter to the monitor board and to the snake.

Or you can buy a complete concert system snake,customized to you band’s specific needs.

When you become a star, the P.A. will be provided for youand you will not have to worry about your snake any more.You will be glad to pawn that responsibility off onto theP.A. guys. Let them worry about it.

IntermediateA hardwired standard fan to box snake, configured for

your mixer inputs/outputs and the length you need. Mostpopular mixers today have either 12, 16 or 24 mic inputsand four returns to the stage. You would ask for a 12x4,100' (or whatever length you need) snake (12 mics, 4returns, 100' long), or a 16x4, 75' snake, etc.

BeginnerNone

So, what kind of a snake do I need?

CHOOSING THE RIGHT SNAKEopportunity for crosstalk anddamage to your equipment. Abetter way to do this is to tapetwo 12-gauge speaker cables

to the outside of a standardsnake. Clumsy and ugly, but

functional and safe.

■ How long do I need the snake tobe? Pro Co’s snake wire is capableof transmitting a balanced signal2,000 feet without much loss.Most portable snakes average100' in length.

■ A weird question you should askyourself is “Is the snake I amconsidering flexible?”

Many snakes are not very flexible,and the time that you will notice thisis the first time you use it. Checkflexibility before you buy. If you aregoing to be setting up several times

a week, this isvery important.Also, if you aregoing to becoiling anduncoiling yoursnake everyweek or moreoften, you willneed to buy amore sturdysnake than youwould need ifyou only movea couple timesa month.

If the wire used in your new snakewas designed correctly, it will last foryears, even with rough use. If the wirewas poorly designed, it will not lastlong. Building very flexible, yet verysturdy snake cable is a science thatfew manufacturers develop correctly.

Solutions:Mixer input connectors are XLRfemales. Mixer left and right stereooutputs are XLR males or 1/4" phonejacks, usually balanced. The “fan”end of the snake must be orderedto match the panel connectors onyour mixer. If these are not orderedcorrectly, you may have to changeout the correct connectors yourself,probably voiding the factory warran-tee for the product.

On stage, microphone inputs inthe stage box are all XLR females.Outputs from the snake to the on-stage amplifiers (or electroniccrossovers) are either XLR males or1/4” phone jacks, usually balanced.

You will need to purchase balancedor unbalanced patch cables that havethe correct ends on them to convertfrom the snake’s outputs to the inputson your power amps. See the sectionin this manual on patch cables.

The secret is to get your poweramplifiers as close to your speakersas possible and run the shortestspeaker cables you can — for goodsound, for less strain on the poweramplifier(s), and less chance oftripping on the cables all over thestage.

Fan to Box Snake,1/4” returns

Fan to Box Snake,XLR returns

1/4” Returns

XLR Female Returns

XLR Females

XLR Females

XLRMales

1/4”StereoPlug

XLRMales

XLRFemales

Page 21

Microphone splittersA single microphone signal (feed)may have to be split to the FOHboard, the recording board, themonitor board and the satelliteuplink if theperformance is alive broadcast.

Each split needsto be isolatedfrom the othersto prevent hum.These splits can behardwired withoutisolation transformers,dangerous unlessyou are using veryexpensive (likeYamaha 4000s)mixers with expen-sive input transform-ers as factoryequipment, or, splitscan be accom-plished with isola-tion transformers —a much safer way toseparate the micsignals into morethan one path, butconsiderablymore expensive(however, notas expensive asbuying Yamaha4000s).

For years wedesignedcustom splitter snakes, with trans-formers and ground lift switchesbuilt in the snake’s stage box to helpwith noise and hum problems. Thenwe designed off-the-shelf 19" (indus-try standard) rack-mountable split-ters to make everyone’s life easier)and lots cheaper.

To see just how complicated aconcert snake system can be, visitpages 16-17 of this guide. A full-sizedposter of this diagram is availablefrom Pro Co for six bucks, includingpostage. Check our websitewww.procosound.com for details.

The Big StuffAs already discussed, snakes typicallyare built with a fan (to plug into themixer) on one end, and a box (intowhich you plug the cables on stagecoming from the microphones andgoing to the power amps). There are“quick disconnects” available thatallow you to detach the fans andboxes from the trunk of the snake.This cuts setup time way down andif you are moving constantly, theyare a great investment.

These snakes are built using time-tested multipin connectors whichare extremely reliable. Nonetheless,they must be handled with morecare than a hardwired version ofthe same snake.

You will not find disconnectsnakes in a store. They are all builtto order, one at a time, because ofcustomization requirements requestedby the particular act needing thesnake.

Regardless of which manufacturerbuilds your snake for you, althoughprice is always a consideration in anypurchase, do not buy somethingbeneath your band’s needs. Pay thelong dollar and get a snake thatworks for you. You may spend $100to $300 more to get what you reallyneed. That’s a lot, but a normal 20-channel, 100' snake is going to cost

Snakes allows us tocombine several balanced(microphone) cables into

one smaller diametermultipair cable, making

setup and teardown muchfaster and easier, with less

spaghetti than wouldotherwise be the case.

$400 to $750. Plan that into yourbudget. Talk to your musical equip-ment supplier about options andcosts up front. If you need a snakeand have not budgeted for it, thesticker shock can be numbing.

If you are strapped for cash, tryto find a good used Pro Co snake.Unfortunately, used snakes arealways at a premium and hard tofind. People call us every week to seeif we have any used snakes to sell.Alas, we do not manufacturer “used”snakes, although if we did, we wouldsell all we could build.

Choosing a snakeis unlike buying anyother cable. Mostcables will not badlydent your pocket-book if you make abad choice. Snakesbite if you let them.

Handwired feedthrough Splitter

Snake

FOH

Monitor

*

A multi-disconnect

snake with twosplits and aDirect FOH

Feed

Recorder

Monitor

FOH

*

* For those observant ones in theaudience, yes, the monitor fan onlyhas mic inputs, no returns. Noreturns are necessary here, so themonitor fan is four channels lessinto the FOH send.

Page 22

CHOOSING THE RIGHT PATCH CABLESPatch cables are short cables whichconnect two or more pieces ofmusical equipment that are generallyless than 5' away from each other.

There are 100’s of different typesof patch cables used:■ in equipment racks■ in keyboard rigs■ in pedalboards or between effects■ in patchbays■ to “Y” two or three pieces of

equipment together■ to “jumper” from one speaker

cabinet to another

The BenchmarkThere is no patch cable benchmark.They come in all shapes and sizesand the connector combinationspossible are mind boggling.

The patch cable situationPatch cables are used for guitar levelsignals, line level signals, microphonelevel signals and speaker levelsignals.

The biggest problem with patchcables is having the right ones at theright time to get through today’sinterface mess aspainlessly aspossible.

The reason the audio industryneeds so many different patch cablesis that, over 50 years, we have beenunable to standardize on one con-nector for one job.

If you get a new TV or get cable TVin your home, the connector on theTV and the one in the wall are alwaysthe same. The connector is called an“F” connector and is universal.

Instrument and line level connec-tors can be 1/4" phone plugs, RCAphono plugs, 1/8" mini plugs, or anycombination depending on the hard-ware we need to connect together.

Balanced signals can terminate atXLR male and female connectors, aswell as 1/4" balanced connectors andbalanced 1/8" mini plugs.

Professional patchbays usually useeither military style 1/4" plugs (alsowidely known as long frame or PJconnectors), or tini-telephone (TTor bantam) plugs.

Typically keyboards and P.A.equipment are at line level, differentfrom instrument, mic and speakerlevel.

Confused yet? All of these connec-tors haveevolvedover 50years andare usedinter-changeably

for these reasons: cost, reliability orreal estate (on the back panels ofequipment).

The ProblemsAfter 26 years of spendingenormous amounts of time

and money learning tohook up this complicatedindustry, we are in awe ofthe standard bearers (theA.E.S. — Audio Engineer-ing Society) total inabil-ity to get anyone toagree to anything.

By its very call out the XLR connec-tor is Pin 1 ground, Pin 2 hot, Pin 3cold. There is still debate in somecamps on whether Pin 2 or Pin 3 is hot.

Manufacturers use whatever jacksthey want to use, depending on backpanel real estate, and costs. In fact,we are concerned enough to feelthat equipment manufacturersignore the real world after theiroutput panels.

Their concern is not making it easyor simple for you to hook up theirgear to anyone else’s. Fortunately forPro Co, that falls on our shoulders.

Although 43% of all the items webuild are 1-off products, never to bebuilt again (at least this year), wethink that is a sad commentary onthe state of the industry.

Our industry flat does not have itsact together; it does not have an “F”connector. Does that mean we, as anindustry, get an “F” in our ability tomake and demand adherence to astandard. We think so. But enoughsoapboxing for one cable guide.

The solutionsPatch cables typically do not needthe durability and flexibility of primaryguitar cables or microphone cables.They do need good shielding andgood sonics. Cosmetics do notmatter a whole lot, since no one willever see them except you or yourroadie.

Nonetheless, Pro Co still makesgreat looking, great sounding,reliable, flexible, well-shielded patchcables because many musicians stillwant the assurance that their rig willsound great, every where, every time.Sacrificing that for a few bucks is notworth the money.

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“One of my problems iskeeping musicians suppliedwith enough patch cables in

the right configuration toget the show on the road.”

Page 23

A word of cautionThere are patch cables availablethat are bubble-packed like fishinglures in a hardware store. There aregenerally very inexpensive and havevery little copper in them (they donot need much copper to get thesignals around, but there is nostrength to the wire itself ). Thesecables have a tendency to quickly“open” (break) or short together theconductors or one of the conductorsto the shield. We do not recommendthem, but in a pinch or if you are on atight budget, they will work to “getyou by”. If you are going to buy oneof these cables, at least buy it in amusic store. These cables can alsobe purchased at stores that sellradios, and theirs are not as good.

Typical patch cables include:

Unbalanced Patch Cables■ 1/4" Phone to 1/4" Phone■ 1/4" Phone to RCA Phono■ RCA Phono to RCA Phono

Balanced Patch Cables■ XLR Male to Balanced 1/4"■ XLR Female to Balance 1/4"■ Balanced 1/4" to Balanced 1/4"■ Balanced 1/8" Mini to Balanced 1/4"■ Balanced 1/8" Mini to Balanced

1/8" Mini■ Balanced 1/8" Mini to XLR male■ Balanced 1/8" Mini to XLR female■ XLR Female to XLR Male (standard

microphone cable)■ TT (tiny telephone) to everything

else■ PJ’s to everything else.■ Sound card cables from your

computer to your speakers (or tobalanced inputs on a mixer, orwhatever the presenter of aspeech wants his/her computerhooked into.

■ Sound card balanced Mini outputto a summed 1/4" phone pluginput.

Get the picture? It never ends.Now we have professional (XLRs),semi-professional (1/4" phone),consumer (1/8" balanced Mini) andcomputer (pick whatever you want)and our job is to hook it all togetherso anything can talk to anything else— so your music, your speech, yourconvention or your message can beheard, with complete clarity, like the1920 inaugural speech we told youabout in the Digital chapter.

A DISSCUSSION ABOUT DIGITAL CABLES30 years ago avery wise mansaid, “Music is aproduct of thetechnology of

the times”.Stradivarius had the technology tomake violins in the 1600’s. In 1723,technology was there to build thepiano. Pipe organs preceded themby many years.

James B. (Jim) Lansing was thefounder of the modern-day JBLloudspeaker manufacturing com-pany. He had the technology toprovide sound for the 1920 presiden-tial inauguration with completeintelligibility for 250,000 people.Many of today’s modern airportpaging and announcement soundsystems have little to no intelligibility.That’s not much progress for 80 years.

Audio has been analog in itstechnology until now. With comput-ers controlling more and more of ourworld, audio is becoming digital in itstransmission.

Analog refers to electronic trans-mission accomplished by addingsignals of varying frequency oramplitude to carrier waves of a givenfrequency of alternating electromag-

netic current. Broadcast and phonetransmissions are both examplesof transmitting through analogtechnology.

The “AES/EBU” (Audio EngineeringSociety/European Broadcast Union)digital audio standard is probablythe most popular digital audiostandard today. Most consumer andprofessional digital audio devices(CD players, DAT decks, etc.) thatfeature digital audio I/O supportAES/EBU.

AES/EBU provides both “profes-sional” and “consumer” modes. Thebig difference is in the format of theirchannel status bits. The professionalmode bits include alphanumericchannel origin and destination data,time of day codes, sample numbercodes, word length, and other goodies.The consumer mode bits have muchless information, but do includeinformation on copy protection(naturally). Additionally, the standardprovides for “user data”, which is a bitstream containing user-defined (i.e.,manufacturer-defined) data.

The physical connection mediaused with AES/EBU are differential,using two wires and shield in (standardlooking) three-wire microphonecable (however, with a specificimpedance).

Alas, this will add great confusionto the world of audio. Now analogconnectors (XLR’s and RCA’s, alongwith mini balanced and 1/4' bal-anced and unbalanced) look just likedigital connectors and the wire usedlooks the same, but the impedancerequired for optimum digital trans-mission is different for analog anddigital. In analog, the two conductorsof the cable carry half of a balancedsignal. In digital one cable carriesboth left- and right-channel audiodata to the receiving device.

Adding confusion to this is theS/P-DIF standard. “S/P-DIF” (Sony/Philips Digital Interface Format)typically refers to AES/EBU operatedin consumer mode over unbalancedRCA cables. Note that S/P-DIF andAES/EBU mean different thingsdepending on how much of a puristyou are in the digital audio world.

Digital describes electronic tech-nology that generates, stores, andprocesses data in terms of two states:positive and non-positive. Positive isexpressed or represented by thenumber “1” and non-positive by thenumber “0”. Thus, data transmittedor stored with digital technology isexpressed as a string of 0’s and 1’s.Each of these state digits is referredto as a bit (and a string of bits that acomputer can address individually asa group is a byte).

There are times when a modemis used toconvert thedigital infor-mation froma computerto analogsignals for

your phone line and to convertanalog phone signals to digitalinformation for your computer.

Digital technology is prima-rily used with new physicalcommunications media, suchas satellite and fiber optictransmission.

So what does this have todo with audio and what arethe standards for the newdigital audio?

James B. (Jim) Lansingwas the founder of the mod-

ern-day JBL loudspeakermanufacturing company.

He had thetechnology to provide

sound for the 1920presidential inauguration

with complete intelligibilityfor 250,000 people.

“One of my problems ishelping musicianskeep analog and

digital cables clearlyidentifed.”

Page 25

S/P-DIF is a standard audio transferfile format. It is usually found ondigital audio equipment such as aDAT machine or audio processingdevice. It allows the transfer of audiofrom one file to another without theconversion to and from an analogformat, which could degrade thesignal quality.

impedance for accurate transmissionis important, shielding is crucial,durability is a really big deal, andclear marking on the wire jacket willbecome an issue as users try to keeptheir audio and digital cables clearlyidentified and separated for properuse, especially in portable situations.

A M.I.D.I. discussion — wheredigital all began in audio

M.I.D.I. (musical instrument digitalinterface) cables are not audio cables.M.I.D.I. is a standard for movingdigital signals around in a musicalsetting between digital keyboards,computers and all the peripheralM.I.D.I. gear used to create today’selectronic music.

Conceived in 1984, M.I.D.I. usesGerman standard 5-pin “DIN” connec-tors and foil-shielded microphonewire to transmit its signals, but usesonly three of the five terminalsavailable on the connector.

A major concern for M.I.D.I. cablesis shielding. Pro Co uses only 100%-foil-shielded wire in its M.I.D.I. cables.Like computers, it is critical that thedigital signals be transmitted abso-lutely accurately without interferencefrom the outside world. It is alsoreally important to keep the digitalsignals between equipment con-tained so that the M.I.D.I. signalsdo not interfere with the lightingcontrollers or other musicians’ rigsor the recording board.

M.I.D.I. cables typically do not takethe stress of instrument and speakercables, and can be lighter-duty innature. Also, since they are not flexedmuch, foil shields are adequate froma reliability standpoint, while offeringthe best shielding available.

M.I.D.I. is still very much around asa standard. Conceived by some verybright people, it is not without itsfoibles, but has withstood the testof time.

The most common connector usedwith a S/P-DIF interface is the RCAconnector, the same one used formost consumer audio products. Also,optical connectors are sometimesused.

As far as the wire is concerned,for the most accurate transmission,AES/EBU requires a two-conductor,shielded wire with a constant imped-ance of 110 ohms (61.7 ohms/km).A stable impedance is specified tohelp keep interface jitter to a mini-mum. Typically polypropyleneinsulation material is used to main-tain the stable impedance. Workingconditions can limit the useful lengthsbetween terminations. Polypropy-lene is a great insulating material foraudio cables as well, second only toTeflon, which is expensive and difficultto extrude into a cable. However, thismakes for a less flexible cable overall.

For S/P-DIF, a coax (single-conduc-tor wire with overall shield) cable isused, with a constant impedance of75 ohms specified.

For comparison purposes, standardmicrophone wire is typically about95 ohms impedance.

The audio cable manufacturers arejust beginning to offer specific cablesfor AES/EBU and S/P-DIF use. Proper

M.I.D.I. is a standard formoving digital signals

around in a musical settingbetween digital keyboards,

computers and all theperipheral M.I.D.I. gear used

to create today’selectronic music.

WHAT TO LOOK FOR IN INTERFACE BOXES

Page 26

There are some points ina sound system where asignal has to be sent tomore than one place.

Direct BoxesWe need direct boxes to send a

signal from a guitar rig to the P.A.system while still allowing theguitarist the freedom to control his/her own tone and volume on stage.A direct box also allows the guitarsignal to be properly split to a Lo-Zbalanced line so that the soundmanor woman can have control over theguitar sound for the audience.

There are 100’s of different directboxes to choose from, from single-use models to rack-mounted 4-unitmodels.

Microphone CombinersWe need microphone combiners

to help us “cheat” a little when weneed extra channels. One scenariowould be that we have two bassdrums to mic and only one channelleft on the mixer. We can combinethe two bass drum mics into a miccombiner with a balanced Lo-Zoutput and get the solution we need.

Yes, this can also be done withmicrophone Y-cables, but this wayaffects the tone and output of themics significantly.

Mic combiners are generallydesigned for single-use applications.

Microphone SplittersWe need microphone splitters to

separate the feed from one micro-phone to two, three or four differentsystems (FOH, monitor, recording,uplink). All these signals must beproperly isolated from each other toprevent problems within one of thefeeds from affecting the purity of thefeed to the others.

Mic splitters are almost alwaysused in large quantities — 16, 24, 32or 40 channels of split (usually to themonitor system) is common. Rack-mounted versions are common, inorder to obtain enough channels to

Let’s talk technicalabout transformersTransformers are held respon-sible for being cure-alls for all P.A.diseases. All a transformer doesis split a signal into two parts (3or 4) , a primary and a secondary(or two secondaries or threesecondaries), while (hopefully)allowing each part of the trans-former to be isolated from theothers to get rid of “hum” in thesystem or to match mismatchedimpedances in two differentpieces of equipment.

There is an art to developingeffective, sweet sounding trans-formers with full range and goodisolation. If you plan to buy acheap direct box (under $50), donot waste your time. It’s a toyand will not work for audio.

Good transformers are expen-sive. You cannot sleaze atransformer’s quality and expectthat you will be satisfied with thesound that comes out of it.

get the job done. Lot’s of mic cables,or snakes with multipin disconnectsare used to be able to hook this alltogether to the rest of the system.

IsolatorsWe need isolators on stage to

break pesky ground loops betweenpieces of equipment connected withunbalanced lines. Also, there aretimes when an act has to perform inan area of high RFI concentration(dirty). The isolation provided by themixing console(s) may just not beenough to filter out unwanted noiseand the system needs a little extrahelp.

These fast-fixers can be as simpleas inline units, designed to be a quicksolution to an individual problem.There include ground lifts, phasereversers, isolation transformers, Lo-Zto Hi-Z adapter transformers, lineoutput transformers and microphonepads.

Isolators can be simple inline unitsor be found in 4- and 8-channelversions suitable for rack-mounting.

SIGNAL SOURCE

MIC INPUT OF MIXING CONSOLE

1/4" (6.3mm)PHONE PLUG

XLRFEMALE

XLRMALE

SIGNALPATH

1/4" (6.3mm)PHONE PLUG

STAGE OR STUDIOAMPLIFICATION (IF USED)

DRUM SYNTH "BRAIN"

PREAMP

DRUM MACHINE

MIXER

AMPLIFIER

KEYBOARD

ELECTRIC GUITARor BASS

MIXER

INSTRUMENT AMPLIFIER

POWER AMP

PREAMP

INPU

T

OUTP

UT

HI C

UTFL

AT

SPKR

INST

GND

LIFT

LO-Z

OUTP

UT