Grimm Audio CC1 User manual

Please read this manual before operating the unit!

TPInLB

3
Table of Contents
Introduction 4
ImportantSafetyInstructions 5
1.Installing 7
2.SignalConnections 8
3.Operation 8
4.SettinguptheStudio 12
5.ProTools 16
6.JitterandPLL’sexplained 18
7.Specifications 23
8.GrimmAudioLimitedWaranty 25

4
Introduction
ThankyouforchoosingtheGrimmAudioCC1CentralClockdistributorforyour
productionenvironment.Thisproductfeaturesarichsetofdistributorfunctions,
baseduponanultralowjitterclockoscillator.Itembodiesourcompanyphilosophy
ofprovidingthemosttransparentsignalchainpossible,enablingyoutoachievethe
bestpossibleresultssonicallyandartistically.LargepartsoftheCC1circuitry,like
theoscillatoranditspowersupplies,useadiscretedesign.BecauseofthisaCC1
hasmorethan700components.Duringconstruction125seperateelementsare
tested.
TheCC1canbeusedinawidevarietyofapplicationssuchas:
•HouseSyncgenerationinaudioand/orvideostudios.Sixteenoutputspermitthe
useofthereliable“star”distributionscheme.TheextremelylowjitteroftheCC1
clockoutputsmaximisesthesoundqualitypotentialoftheattacheddevices.Incase
youneedtoslaveyoursystemtovideoclock,pleaseinsertaGrimmAudioVCC,
‘videotowordclockconverter’beforetheclockinput.
•Clockstabilityimprovement,andhenceimprovedsound,ofdigitallivedesksand
digitalsnakes.
•Clockdistributioninbroadcaststudios.
•Improvementofyourhomeaudiosystem.Forinstanceinconjunctionwithword
clockequipeddevicesorasreclockunitinbetweenatransportormediasystem
andaDAconverter.
Thismanualdescribeshowtosetuptheunitinyourstudio,liveorhomeenviron-
mentaswellasimportanttipsonhowtogetthebestperformancefromtheCC1.In
addition,somebackgroundinformationontheunit’soperationisprovided.
Wehopethisinvestmentwillbringyoumanyyearsofcreativeenjoymentandhelp
youachieveyourgoals.

5
Important Safety Instructions
Grimm Audio gaat er van uit dat u deze Engelstalige tekst volledig begrijpt. Als u hier moeite
mee heeft dient u contact op te nemen met Grimm Audio. Op verzoek sturen wij u een vertaling
toe.
Grimm Audio nimmt an, dass Sie diesen Englischen Text völlig verstehen. Wenn notwendig,
nehmen Sie bitte Kontakt auf mit Grimm Audio. Auf Wünsch wird Ihnen eine Übersetzung zu-
geschickt.
Grimm Audio suppose que le lecteur comprend parfaitement le texte en Anglais ci-dessous. En
cas de doute s.v.p. contacter Grimm Audio. Si necessaire, on pourra vous envoyer une traduc-
tion.
Grimm Audio da por supuesto que el texto en versión Inglesa no ofrece ninguna duda de in-
terpretación y se entiende integramente. Si este no fuese su caso rogamos contacte con Grimm
Audio quien, a petición, se encargaría de enviarle la correspondiente traducción.
Please follow these precautions when using this product:
1.Readtheseinstructions.
2.Keeptheseinstructions.
3.Heedallwarnings.
4.Followallinstructions.
5.Dangerousvoltageisinsidethisapparatus.Openingisonlyallowedbyqualified
servicepersonnel.
6.Verifylinevoltagebeforeuse.
7.Donotdefeatthesafetypurposeofthepolarizedorgrounding-typeplug.A
polarizedplughastwobladeswithonewiderthantheother.Agrounding-typeplug
hastwobladesandathirdgroundingprong.Thewidebladeorthethirdprongare
providedforyoursafety.Whentheprovidedplugdoesnotfitintoyouroutlet,con-
sultanelectricianforreplacementoftheobsoleteoutlet.
8.Protectthepowercordfrombeingwalkedonorpinched,particularlyatplugs,
conveniencereceptables,andthepointwheretheyexitfromtheapparatus.
9.Unplugthisapparatusduringlightningstormsorwhenunusedforlongperiods
oftime.

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10.Donotusethisapparatusnearwater.
11.Donotusethisapparatusoutside.
12.Donotexposetheapparatustodrippingorsplashing.Donotplaceobjects
filledwithliquids(flowervases,drinkcans,coffeecups,etc)ontheapparatus.
13.Cleanonlywithadry,soft,non-fluffycloth.Donotsprayanyliquidcleaneronto
thecabinet,asthismayleadtodangerousshocks.Donotsprayanyliquidcleaner
ontothefaceplate,asthismaydamagethefrontpanel.
14.Installinaccordancewiththemanufacturer’sinstructions.
15.Donotinstallnearanyheatsourcessuchasradiators,heatregisters,stoves,or
otherapparatus(includingamplifiers)thatproduceheat.Avoidexposuretodirect
sunlight.
16.Useonlyattachmentsoraccessoriesspecifiedbythemanufacturer.
17.Useonlywithacart,stand,bracket,ortabledesignedforusewithprofessional
audioormusicequipment.Inanyinstallation,makesurethatinjuryordamagewill
notresultfromcablespullingontheapparatusanditsmounting.Ifacartisused,
useprecautionwhenmovingthecart/apparatuscombinationtoavoidinjuryfrom
tip-over.
18.Thisunitrunsslightlywarmwhenoperatednormally.Operateinanormalventi-
latedarea.Ifthisproductwillbeinstalledinarack,makecertainthereissufficient
airmovementwithintherack.
19.Referallservicingtoqualifiedservicepersonnel.Servicingisrequiredwhenthe
apparatushasbeendamagedinanyway,suchaswhenthepower-supplycordor
plugisdamaged,liquidhasbeenspilledorobjectshavefallenintotheapparatus,
theapparatushasbeenexposedtorainormoisture,doesnotoperatenormally,or
hasbeendropped.
20.WARNING: Toreducetheriskoffireorelectricshock,donotexposethisappa-
ratustorainormoisture.

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1. Installing
Unpacking and Inspection
YourCC1wascarefullypackedatthefactoryandthecartonitcameinwasde-
signedtoprotectitfromthetrialsandtribulationsofshipping.Keeptheboxandall
packingmaterials,sothatintheunlikelyeventthatyouneedtoreturntheCC1for
servicing,youcandososafely.
Mounting the CC1
TheCC1canmountinanystandard19”rack.TheCC1doesnotproduceRFfields
norissusceptibletothem.Youcanpositionitnearotherdigitalgearsuchascom-
puteranddiskrecorderswithoutworry.Ingeneralitisagoodideatokeepsome
distancebetweenmonitors(LCDandCRT)andaudioandwordclockcablesbecause
ofriskofinducedlowlevelnoiseduetostraymagneticfields.
GrimmAudioproductshavearealwoodfaceplatethatprovidesabeautifuland
vividappearance.Tomaintaintheoutstandinglooks,oneisadvisedtotakesome
precautions:
-DonotplacetheCC1inhumidnorverydryenvironments.Thewoodmightcrack.
-Donotusechemicaloralcoholbasedcleaneronthewood.
AC Power Hookup
TheCC1hasalinearpowersupplythatneedstobefactorysetforyourlocalline
voltage.MakesuretocheckthenotedlinevoltageonthebackbelowtheIECcable
entrance(‘wiredfor...V’)andverifythatthiscomplieswithyourlocallysupplied
linevoltage.GrimmAudiocannotberesponsibleforproblemscausedbyusing
theCC1withimproperACwiringorvoltage.SincetheCC1doesnothaveapower
switchonthefrontpanel,aconvenientwaytopowerdowntheunitistousea
powerstripequippedwithaswitch.

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2. Signal Connections
TogglesMaster44.1/48kHzandSlave
Togglesgroup1sampleratemultiplicationfactor
Togglesgroup2sampleratemultiplicationfactor
AES3-out
(follows
AES3-in when
available
and selected,
otherwise
group 2)
AES-in
lockstatus
Inputs
(AES3-in also
for reclocking
purpose)
AES-out
behavior
(thru or
mute) Impedance
group1
(75 Ohm
or Lo-Z)
Impedance
group2
(75 Ohm
or Lo-Z)
Phaseof
BNC11,
12,13,14
(normal or
180°)
Outputs
group1
Outputs
group2 Indication
offactory
setline
voltage
value
unlock
behavior
(hold or
mute)
3. Operation
Master mode
Theleftmostfrontpanelpushbuttonselectsbetweentwobaseclockrates:44.1kHz
or48kHz.Thetwootherpushbuttonsdeterminetheactualclockfrequencytrans-
mittedacrossthe16BNCoutputs.Theycontrolintwogroups.Group1arechan-
nels1-12.Thesecondpushbuttonsetsthemultiplicationfactorforthisgroupto
1x,2xor4x.Group2arechannels13-16,andtheirmultiplicationfactorissetby
thethirdpushbutton.Setting“48kHz”usingtheleftmostpushbutton,“1x”onthe
middleselectorand“2x”ontherightmostselectorwillsettheclockrateongroup1
BNC’sto48kHzandongroup2BNC’sto96kHz.

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TheAES3outputhastwofunctions,dependingonthesettingofthedipswitch
marked“aes”ontherear.Itdetermineswhethertheaudiocontentfoundatthe
AES3inputispassedthroughtotheoutput(“thru”)ornot(“mute”).In“mute”mode
theAES3datawillbeblackandrunattherateselectedforgroup2.In“thru”mode,
theAES3outputwillobviouslyrunatthesamerateastheAES3input.Onlossof
inputsignal,theoutputwillremainatthesamesamplingrate.
TheexactbehaviouroftheAES3outputinmastermodedependsontheusecase:
1.NosignalconnectedtotheAES3input.TheAES3outputisablacksignal(no
audio)withthesamesamplingrateastheGroup2BNCoutputs.Thechannelstatus
bitsindicate“Grade1reference”iftheCC1hasgonethroughtheoptionalfrequen-
cycalibration,otherwise“Grade2reference”.TheAESlockindicatorontherearis
off.
2.AsignalisappliedtotheAES3inputthatisnotsynchronoustotheCC1.The
AES3outputisablacksignalwiththesamesamplingrateastheGroup2BNCout-
puts.TheAESlockindicatorontherearblinks.
3.AsignalisappliedtotheAES3inputthatissynchronoustotheCC1,butthe“aes”
dipswitchissetto“mute”.TheAES3outputwillstillbeblackandsynchronous.The
presenceoftheaessignalhasnoeffect.In“master”modewiththe“aes”dipswitch
setto“mute”,anysignalattheAES3inputisbasicallyignored,exceptthatthe“aes
lock”lightontherearwillbeontoindicatethepresenceofasynchronousinput.
4.AsignalisappliedtotheAES3inputthatissynchronoustotheCC1,andthe
“aes”dipswitchissetto“thru”.TheAES3outputfullycopiesaudioandsubcode
data(butnotthejitter!)fromtheAES3input.InthismodetheAES3outputwill
neverindicate“grade1”asAES11requiresablacksignal.The“aeslock”lightison.
5.Iftheinputsignalislostfromcase4,thesamplingfrequencysettingisretained,
assuddenlossofsignalismostlikelyaccidental.Thisisdifferentfromcase1
whereanAES3inputsignalwasneverpresent.IftheremovaloftheAES3inputwas
onpurpose,changingthegroup2multipleonthefrontwillreturntocase1,and
theAES3outputwillonceagainbesynchronoustotheselectedmultipleofgroup2.
Slave mode
Slavemodeisthethirdsettingontheleftmostselector.Inslavemode,theCC1will
lookatthewordsyncinputaswellastheAES3inputforavalidsignal.Slavemode
permitsthefollowingusecases:
1.Wordsynconly.Uponselectionofslavemode,theCC1selectsthewordsync
input.Themiddleandrightselectoronceagainsetgroups1and2toamultipleof
thebaserate.TheAES3outputwillbeblack,synchronisedtogroup2andthechan-

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nelstatusmarked“noreference”.Uponlossoflock,theoutputfrequencywillbe
heldconstant,seecase4.
2.AES3only.Uponselectionofslavemode,theCC1selectstheAES3input.The
“aes”dipswitchattherearselectswhethertheaudiodataistransmitted(thru)or
not(mute).Inthrumode,theAES3outputwillobviouslyrunatthesamemultipleas
theAES3input.Inmutemodeitwillbesynchronoustogroup2,audioisblackand
marked“noreference”.Uponlossoflocktheoutputratewillbeheldconstant,see
case4.The“AESlock”lightontherearwillbeonaslongastheCC1PLLislocked.
3.BothAES3andwordsyncarepresent.Wordsyncwilltakeprecedenceoverthe
AES3input.In“thru”modetheAES3outputwillproduceajitter-freecopyofthe
AES3input,providedtheinputsignalissynchronous.In“mute”modetheAES3
inputwillbeignoredaltogether.UponlossoftheAES3inputtheAES3outputwill
reverttoblack.Uponlossofthewordsyncinputtheoutputfrequencywillbeheld
constant(within1ppmofthelastdetectedfrequency)andthefrontslavelightwill
blinktoindicateanerror.Thefaultconditionisclearedeitherbyreattachingthe
wordsyncorbycyclingthesourceselectorthroughthetwomastermodesbackto
slavemodetoforcetheCC1tolocktotheAES3signalinstead.TheCC1willnever
automaticallyswitchfromwordsynctoAES3topreventclockloops.
4.NovalidsignaloneitherwordsyncorAES3input.Theresponseisnowdeter-
minedbythedipswitchnamed“unlock”.Whensetto“thru”,theclockfrequencywill
beheldconstantwithin1ppmofthelastvalidmeasuredfrequency.Whensetto
“mute”,theoutputswillbemuted.Inbothcasestheslavelightwillblinktoindicate
anerror.The“mute”modeisadvantageousatforinstancepostproductionwhere
theclockusuallyisoutofsightinamachineroom.Uponlossoflock,allclocksdis-
appearandyoursoftwareautomaticallyprovidesawarning.The“thru”modehasan
advantageinforinstanceliverecordingorPublicAddress.Heresoundshouldnever
mute,whateverhappens.
Lock indication
TheCC1detectswhethertheinputsignalisamultipleof44.1kHzor48kHz,and
indicatesthisontheLEDsabovethesourcepushbutton.Thefrequencymultiple
settingsofgroups1and2remainassetbytheuser.WhiletheCC1acquireslock,
theslavelightwillblink.Thiscantakeupto20s,onaccountoftheCC1’sextremely
slowPLLdesign(seechapter6,“JitterandPLL’sexplained”).Oncefrequencylock
isachieved,theslaveLEDwillcomeoncontinuously.ThePLLwillthensettleto0º
phaselockwiththeinputinanevenslowermode.Thesmallestachievablephase
errordependsmostlyonthestabilityoftheincomingclock.Thestatic(average)
phaseerrorisfactory-alignedtowithin50ns.

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The“lock”LEDontherearindicatestheAES3receiverstatus:
1.Off:NoAES3signalpresent.
2.On:AES3signalpresentandfoundtobesynchronouswiththeCC1.
3.Blinking:AnAES3signalispresentbutitisoutofsyncwiththeCC1.
Impedance
The“impedance”DIPswitchesontherearalloweachindividualoutputtobeset
tolow-impedance(25ohmstypical)orcharacteristic(75ohms)impedance.The
switchesarefactorysetto75ohms.Shouldthereceivingdevicehaveproblems
recognisingthewordsyncsignal,youmighttrythelowimpedancesetting.
Wordsyncconnectionsareusually5Vsquarewavestransmittedover75ohm(vid-
eo)coaxcables.Althoughthewordclockfrequencyitselfisrelativelylow,thetran-
sitionsaresteep.Takenasawhole,wordsyncisawidebandsignal,necessitating
characteristicterminationatleastatoneendofthecable.Single-terminatedlines
areusuallyterminatedonthesourceend.Betterstillisseriesterminationonthe
transmitendandparallelterminationonthereceivingend.Thisminimisesreflec-
tionsevenwhenthecableimpedanceisnotexact.Doubleterminationlikethispro-
ducesa6dBloss,resultingina2.5Vsignal.AllGrimmAudioproductsaredesigned
toworkinthismanner.
Thereisnostandarddefiningwordsyncconnections.Asaresult,impementations
varyacrossmakes.Outputsmaybeseriesterminatedorlowimpedance,DCorAC
coupled.Inputsmaybeparallelterminatedorhighimpedance.Thisyields8permu-
tations,allofthemencounteredinthewild.TheCC1inputwillcorrectlyinterpret
allvariantswithoutusermanipulation,buttheimpedanceoftheCC1’soutputs
mayneedtobesetlowinsomecases.Aparallel-terminatedinputexpectinga4V
inputsignalwillonlyworkwiththeCC1’soutputimpedancesetlow.Afairnumber
ofproductswerefoundtohaveparallelterminatedinputbutstopworkingaround
2.5VwhichiswhytheCC1putsoutaslightlyhigher-than-normalvoltageinorderto
allowcorrectoperationinthefactorypresetmode.Nevertheless,someequipment
willonlyrespondcorrectlywhentheoutputimpedanceDIPswitchissettolow.
Phase
Channels11to14canbepolarity-reversed(180ºphaseshift)tocaterforequip-
mentthatusesthefallingedgetosynchroniseoninsteadoftherisingedge.Should
youencounteroperationalproblemswithequipment,eventhoughitislocked,
checkthemanualforanymentionofclockphaseandtrythe180ºswitchsetting.

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AES and unlock switches
The‘aes’and‘unlock’switchescanbesetto‘‘mute’or‘thru’.Thebehaviorofthe
CC1inthesemodesisdescribedinChapters‘Mastermode’and‘Slavemode’.
Key Lock mode
IfyourCC1isusedinonesettingmostofthetimeyoucanuse“KeyLock”modeto
preventclockingerrorsbyaccidentalpressingofcontrolbuttonsontheCC1’sfront
panel.InthismodetheCC1doesnotrespondtothepushofanybutton.“KeyLock”
modeisengagedbyholdingthe“44.1/48/Slave”buttonduringpowerup.Itwill
thenlockthemodethatwassetbeforethelastpowerdown.Toleave“KeyLock”
mode,holdthe“44.1/48/Slave”buttonduringpowerupagain.
4. Setting up the Studio
Inadigitalstudioallequipmentwillneedtobesynchronised.Ifallthereisaretwo
boxes,onesendingandonetransmitting,allthatisneededisadigitalsignaland
therecipientwilllocktothat.Whenmultiplesourcesarefeedingintoonerecipi-
ent(e.g.adigitaldeskconnectedtoseveraldigitalrecordersandconverters),all
sourceswillneedtobesynchronous.Thisiswhatahousesync(akamasterclock)is
for.Severalformatsareinuse.TheAESpromotesastandardcalledAES11thatuses
anAES3link,butmostequipmenttendstouseawordsyncsignalonaBNCconnec-
tor.TheAES11standardistobeamendedtoincludethispractice.Wethinkthisisa
goodmove,sincethepurityofaclockrecoveredfromanAES3linkisrathersuscep-
tibletoissueslikecablelengthandbandwidthlimitations.TheAES3outputonthe
CC1isprovidedtocaterforthefewequipmentthatneedsAES11overAES3.When
theoutputisnotusedforthispurpose,itdoublesasajitterremovalfunctionfor
anyAES3signal(provideditissynchronouswiththeCC1).
Moststudiosthathaveintroducedahousesynchavenoticedachangeintheoverall
soundqualityoftheirequipment.Usuallyforthebetter,sometimesfortheworse.
Atissueisjitter(akintowowandflutter,butthenappliedtothesamplingclock).
Chapter6“Jitterexplained”willgointomoredetails.Theimportantpointtoremem-
beristhatjitteraffectsaudioqualityonlyatpointsinthechainwhereanactual
time-basedconversionistakingplace,typicallyADandDAconvertersbutalso
increasinglyasynchronoussamplingrateconverters.

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Connection
TheCC1willusuallybelocatedinthemachineroom.Eachdeviceconnectedtothe
CC1issetto“slavetowordsync”.Thebestconnectionschemeis“stardistribu-
tion”witheachoutputoftheCC1connectedtoonedevice.Thesixteenoutputswill
normallysuffice.Daisychainconnectionsarebestavoided,asareT-junctioncon-
nections.Thelatterwillmostlikelyfailanywaybecauseofthelackofstandardisa-
tionofterminationimpedanceandsignallevel,nottomentionmechanicalfailureof
T-junctionsthemselves.
Trytopreventcirculatinggroundcurrentsthroughthecoaxcables(groundloops).
Ascoaxcablesgo,theyareunbalancedandcurrentsflowingthroughthecable
shieldswillimposeanerrorvoltageonthesignal,causingjitteratthereceivingend
thatwasn’tthereatthetransmittingend.Onecommoncauseofcirculatingcurrents
isleakagecurrentthroughthepowersupplyofanungroundedproduct.Anotheris
voltagedropbetweentheearthgroundconnectionbetweendevicesthatarelo-
catedfarapart.Minimizingtheloopareaencircledbytheentireloop,comprising
thewordsynccableandthemainscordsisusuallyagoodidea.Byallmeans,never
defeatthesafetyearthconnectionofanydevicethatisdesignedtohaveanearth
connection.Liftinggroundsmayproducealethalshockhazard.
TheCC1itselfhasalow-impedancereferenceplaneattherear,insuringthatit
willneverbeaffectedbycirculatingcurrents.Notallequipmentisdesignedinthis
manner.Incaseyoursystemholdsinterfacingequipmentthatissensitivetoground
loops,GrimmAudiohasanisolationtransformeravailableondemand(CI1).Such
devicesdegradeclockqualitysomewhatsotheyshouldbeavoidedwhendriv-
ingequipmentofwhichtheAD/DAsectionisused.Whenacurrentloopinvolving
severalpiecesofgearneedstobebroken,itisbesttoinstalltheCI1inlinesfeed-
ingnon-performance-criticalequipmentsuchasdigitalI/Osoundcards,andtouse
normal,directconnectionsbetweentheCC1andanyAD/DAconvertingequipment.
AES3 reclocking
Apartfromthewordsyncinputandsixteenoutputs,theCC1alsosportsanAES3
inputandoutput.TheoutputcancarryanAES11DARSsignalbutitmayalsobe
usedtotransmitare-clocked(de-jittered)copyofthesignalattheAES3input.This
maybeusefulwhendrivingajittersensitivedevicelackingawordsyncinput,most
typicallyanoutboardDACinthemonitoringsystemoradigitalloudspeaker.
Thereclockingfunctionisavailableinallconfigurations,thatis,master,slavedto
wordsyncorslavedtotheAES3inputitself.Apartfromthelattertrivialcasethis
impliesthatthesourceoftheAES3signalshoulditselfbesomehowsynchronised
totheCC1.Settingthe“aes”switchto“thru”activatesthereclockingmode,pass-
ingmaximallyjitter-freesignaltoe.g.aDAC.Inmostcasesthiswillimprovereplay
qualitysignificantly.

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Inconsumeruse,mostequipmentfeaturesRCAS/PDIFconnectorsinsteadofXLR
AES3connectors.TofacilitateHi-FiuseoftheCC1,allourconsumerunitsare
shippedwithanS/PDIF<->AES3conversioncableset.
Clock Loop
Aclockloopisarunawaysituationwheretwodevicesareslavedtoeachother,for
instancetheCC1slavedtoarecorderwhichinturnisslavedtotheCC1.Neitherde-
viceistheclockmasterandtheresultwillusuallybethattheclockfrequencyends
upatanextremeofthetuningrangeofoneofthedevices.BeforesettingtheCC1
toslave,insurethattheclockinputoriginatesfromamaster.
PLL setting in attached devices.
Audiodevicescapableoflockingtoanexternalclockuseaphase-lockedlooptodo
so.Detailsofthisarecoveredinourwhitepaper“PLLandclockbasics”thatcanbe
foundontheinfopageofourwebsite.AnimportantthingtoknowforaCC1useris
thatsomeproductshavetwomodes,usuallycalled“fast/wide”or“slow”.Theslow
settinghasthebestsuppressionofincomingjitter,andistheoptimumchoicewhen
theincomingclockispolluted.Thedownsideoftheslowsettingisthatthejitterin
therecoveredclockisfullydominatedbytheclockoscillatorthatformspartofits
PLL.Iftheincomingclockhappenstobemuchstablerthanthat,theslowmodewill
actuallyendupaddingjitter.Thelatterscenarioisalmostguaranteedtobethecase
withtheCC1,whichissignificantlycleanerthananyclockoscillatorwe’vefound
incommerciallyavailableaudioproductssofar.Asarule,inthiscaseitisusually
bettertoselectthe“fast”mode.Infastmode,thePLLwilltracktheincomingclock
morecloselyandiftheincomingclockisextremelyclean,thesamewillgoforthe
regeneratedclock.
ProductsthathaveafixedslowPLL,suchasthosefromApogee,dCS,LynxorPrism
Sound,willimprovecomparablylittlecomparedtoproductswithaswitchableor
relativelyfastPLLlikethosefromAvid,LavryEngineering,MOTU,Mytec,SSLor
RME.Digitalloudspeakersthatfeatureawordclockinput,likeDynaudioAir,will
alsobenefitfromslavingtotheCC1.
Syncing to Video
Beforecomplicateddigitalstudiosbecamepractical,videostudioshavebeenus-
inghousesyncsfordecades.Assoonasmorethanonecameraisused,allsources
needtobesynchronised.Apartfromatimebasereferencethereisalsoaneed
toknowtheactualtimingofaframe.Thisinformationisprovidedbytimecodes.
Althoughthetimecodesignalisofcoursesynchronouswiththevideosync,itis
usuallytransmittedseparately.Insomecasesthe“LTC”codeisusedasmainvideo

15
sync,butfortunatelyitisgoingoutoffashion.LTCisprobablytheleaststabletime
referencearound.
Enterdigitalaudio.Theaudiotracknowneedstobesynchronisedtothepicture.
Wordsynchasabettertimeresolutionthanvideosync,butstillthemostcommon
practiceislockingtheaudioclocktothevideoclock.Evenmoderndigitalvideopro-
ductionpracticetendstolockaudiotoananaloguevideosignal.Thisisunfortunate
becauselowjitterisnotexactlyadesignspecforavideosyncgenerator.
TheCC1cannotslavetovideosyncdirectly.Inordertoavoiddirectcrosstalkbe-
tweentheblack-burstgeneratororreceiverandtheaudioclock,wehaveomitted
videosyncfunctionality.OurbestadviseistousetheCC1astheaudiomaster
andslaveallvideototheaudiowordsync.Ifyouneverthelessdoneedtoslavethe
audiosystemtovideosyncyoucaneitherbuyourVCC‘VideotoWordClock’con-
verteroruseanyothergenericvideotowordclockconverter.Connecttheretreived
wordclocktotheCC1’swordclockinputandhavetheCC1cleanupthesyncand
distributeclocktotheaudiodevicesasusual.Theextraordinarystabilityofthe
CC1’sPLLwillmakesuretheresultcomesascloseaspossibletomakingtheaudio
chainmaster.
Hints
•Selectdecentquality75Ohmcoaxcablesandcertainlydonotskimponthequal-
ityoftheconnectors.
•Makecablesnolongerthannecessary.
•Cablesaddpropagationdelay.Itisexceedinglyrarefordifferencesinclockphase
toaffecttheinteroperabilityofconnectedaudioequipment,butifithappens,using
equallengthcablesthroughouthelps.
•Disconnectunusedgear.
•IdeallydonotleavethewordclockinputconnectedwhentheCC1ismaster.
Althoughunlikely(theCC1hasarelaytoactivelydisconnecttheinputwhennotin
use),thereisapossibilityofcross-talkfromtheinputclocktotheoutputs.Like-
wise,donotleaveanAES3cableattachedifnotneeded.

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5. Pro Tools
AvidProToolsisbyfarthemostcommonDAW,warrantingaspecialsectionon
howtosetuptheCC1inaPTrig.Inourexperiencedescribedmethodistheset-up
thatleadstothebestsoundquality.Anydeviationfromthismethodmightgiveyou
stablesync,butwillprobablynotbesonicallyoptimal.
Pro Tools in music production, CC1 master
ProTools192interfacesfeaturea“LoopSync”functionwhereclockcablesarecon-
nectedinaring:every“LoopSyncin”isconnectedtothenextunit’s“LoopSync
out”,thelastunitconnectstothefirst.Likeinanycorrectclocksetup,oneunitis
masterandallothersslave.TheadvantageofLoopSyncisanyunitcanbedesig-
natedmasterandrunonitsinternalclock.Allothersslavetothatunit.TheLoop
Syncinputofthemasterunitisignoredandeffectivelyanordinarywordclockdaisy
chainresults.NowifProToolsistoslavetowordclock,theunitthatreceivesthe
wordclockalwaysbecomesloopmaster,theothersautomaticallyslavetoLoop
Sync.WecanmakeuseofthisfeaturebyfoolingthesystemintobelievethatLoop
Syncisinuse,whileactuallyastarclockdistributionisutilized.Starclockdistribu-
tionhastheadvantagethatitismorefailsafethandaisychainingandjittergainof
subsequentPLL’sisavoided.
•ConnectanoutputofCC1’sgroup2tothe“ExternalWordClock”inputofthefirst
unitinthechain(ifpresenttheSyncI/O,otherwisethefirst192).
•ConnecttheoutputsofCC1’sgroup1totheLoopSyncinputofeach“192”inter-
face.Every192getsitsownconnectiontotheCC1(stardistribution).Makesure
group1issetto‘x1’.
Incaseyouneedtorunhighersampleratesthan44.1or48kHz,onlysetgroup2
ontheCC1frontpanelto“x2”or“x4”andleavegroup1on“x1”.ThisbecausePro
Tools“ExternalWordClock”inputneedstoreceivetheactualsamplerate,butthe
LoopSyncinputsalwaysrunatthebaserate.
•Softwaresettings:
Setup – session setup
1.SetSyncsourceto“WordClock”.Thisconfiguresthefirstunittolocktoex-
ternalwordclockandtheotherstoloopsync(indicatorslightup).
Pro Tools in music production, CC1 slave
AnalternativesetupwhenusingaSyncI/Oasfirstunitinthechainistoassignthe
SyncI/OmasterandslavetheCC1toitsLoopSyncoutput.Theadvantageisthat

17
thewholesystemwillautomaticallytracktheproject’ssamplerate.Disadvantage
isthatintheoryjitterontheCC1’soutputswillbeslightlyhigher.TheCC1’sjitter
attenuationhoweverissolargewedonotexpectthistobeaproblem.
•ConnecttheLoopSyncoutputoftheSyncI/O(whichisfirstunitinthechain)to
thewordclockinputoftheCC1.PutCC1inslavemode.
•ConnecttheoutputsofCC1’sgroup1and/orgroup2totheLoopSyncinputof
each“192”interface.Every192getsitsownconnectiontotheCC1(stardistribu-
tion).Makesuregroup1and2aresetto‘x1’.
•Softwaresettings:
Setup – session setup
1.SetSyncsourceoftheSyncI/Oto“Master”.All192interfacewillautomati-
callyswitchtoLoopSync,whichistakencareofbytheCC1.
Pro Tools in post pro.
Hereyou’llneedtosynctovideoandtimecode.Asoutlinedabove,setthevideo
equipmenttolocktowordsyncoruseavideosyncgeneratorthatacceptsaword
syncinputfromtheCC1.NaturallytheProToolshardwareisreceivingwordclock
directlyfromtheCC1.AlsoconnectvideosynctotheSyncHD,itwillbeusedjust
fortimecodesynchronisation.
Thewordclockconnectionsareasdescribedintheformerparagraphs“ProTools
inmusicproduction”.Specialattentionisneededforthetimecodeconnection.Up
tillProTools8therewasnowayofcombiningtheSonyP2“MachineControl”time
codesignalwithanexternalwordsyncliketheCC1.SelectingSonyP2forcedthe
SyncI/Otoslavetovideosync.WithcurrentversionsofProToolsyoucanlock
towordclockwhileatthesametimeusingthevideorefinputontheSyncHDfor
frameedgealignmentofP2sync.However,thisonlyworksforPALandNTSC,not
forhidefrates.Itishopedthatafuturesoftwareupdatewilladdressthis.Inthe
meantime,forhidefproduction,pleaseusethefollowingworkaround.
SincethereisnosuchissuewithLTC,wegettousethreeconnectionstotheSync
HD:wordclock,LTCandSonyP2forpuremachinecontrol.Forclocking,havePro-
Toolsslavetowordclockasdescribedinthismanual.Inthiscasedonotconnect
videosynctotheSyncHD.Thisinsuresthat,ifyouhappentoaccidentallyswitchto
thevideosyncinput,yougetaclearerrormessagetoalertyoutotheproblem.For
timecodeandmachinecontrol,followthenextsteps:
•Softwaresettings(takecaretoexecutethefollowingstepsintheorderde-
scribed):

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Setup – Peripherals
1.Onthe“Synchronisation”tab:selectdevice“SyncHD”andport“any”(theLTC
inputwillbeautomaticallyselected)
2.Onthe“MachineControl”tab:tick“9pinsserial”(SonyP2).Untick“useserial
timecodeforpositionalreference”.LeavingthisoptiontickedcausestheSync
HDtotrysyncingtovideosyncinsteadofwordsync.Anadditionaldisadvan-
tageofSonyP2isthatitdoesnotsporta“continuousresync”likeLTC,signal-
ingtimecodeonlytogetherwithtransportcommands.
Setup – Session setup
3.SetSyncSourceto“WordClock”(thepreviousstepwillhaveautomatically
selectedvideosyncinstead,hencetheneedforexecutingthestepsinorder).
TheLoopSyncindicatorswilllightup.
Controllingtheexternalmachinecanbedoneintwoways:
a.ThetransportbuttonsonProToolscontrolthemachineviatheSonyP2interface.
ThemachinegeneratesLTC.ProToolsisslavedthroughtheSyncI/O’sLTCinput
oranyotherLTCtoMTCconverterconnectedtoyourcomputer.Lockisachieved
withinonesecond.Thisisthepreferredmethod.
b.ProToolsiscontrolleddirectlybyitstransportbuttons.Theexternalmachine
locatesandgetsintoplaythroughSonyP2locatorcommands.Theuserselectsa
cuepointandhitsplay.Theexternalmachinewillrewindtothistimecodeminusa
pre-rollandstartsrolling.ProToolswaitsuntilitseesthecorrecttimecodecoming
back(ProToolsslavestotheLTCofthemachine).Apotentialproblemoccurswhen
theexternalmachinefailstoachievesyncduringthepre-rollperiod.Whenevery-
thingisslavedtowordsyncthereislittlechanceofsuchathinghappeningandone
secondofpre-rollshouldsuffice.Whileplaying,ProToolswillrunintriggersync
mode.Thatis,onceit’sstartedplayingitwillignorepositionalinformation,verify-
ingonlythattimecodeisstillrunning.Thismethodmayforinstancebeselected
whenusingharddiskvideoplayers.
6. Jitter and PLL’s explained
Jitterisaninstabilityinthetimingofaclocksignal.Ideallytherisingorfalling
edgesofaclocksignalareallseparatedbyexactlythesameamountoftime.In
reality,thetimingismoreuncertain.Thegraphbelowshowsthetime-domainview
oftheproblem.

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Astableandajitteryclocksignal
Wecanalsolookattheproblemspectrally.Anidealclockhasonlyasinglefrequen-
cycomponents(andharmonics).Allenergyisconcentratedonaninfinitelynarrow
frequencyband,seethetoppicturebelow.Whenjitterispresent,sidebandsoccur.
Somespectralenergyislocatedawayfromtheclock.Thefasterthetimingchatters,
thefurtherawayfromthemainfrequencyyou’llfindenergy.
frequency
frequency
Amplitude Amplitude
Jittery clock
Jitter-free clock,
slightly off the
ideal frequency
Theredcurveinthebottomgraphshowsonlyrandomjitter.Sometimesjitter
isperiodicalandthenyouwouldn’tseeasmoothslopebutsharppeaks.Anim-
portantnoteisthatfrequencyaccuracyhasabsolutelynothingtodowithjitter
atall.Theredgraphshowsajitteryclockwithanexactlycorrectfrequency,say
44100.0000000Hz,theblueoneshowsaclockthat’ssomewhatoffbutotherwise
brilliantlystable.Afrequencyerrorcanbeannoyingfromapracticalperspective,
Spectraofclocksignals

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butasfarassignalqualityisconcernedyou’rebetteroffwithastableclockatan
inexactfrequency.
Jitterisnotaprobleminfullydigitalprocesses.Aslongasitisn’tsolargethata
processorcan’tdistinguishthepreviousbitfromthenext,all-digitalprocessesare
completelyindifferentaboutjitter.Theproblemoccurswhenyougofromtheana-
loguedomainintothedigitaldomainorback.Digitalaudiopresumesuniformsam-
pling.Thatway,givenastringofnumbersandknowledgeofthesamplinginterval,
youcanperfectlyreconstructasampledsignal.Withjitterthattheoryfallsflatonits
back.
Imaginethesignalontop.TheADconvertersamplesitatneatlyuniformintervals.
TheDAconverterreconstructsthecorrectvaluesbutitgetsthetimingwrong.The
differencebetweentheredandbluecurveshowstheerror.Ortaketheconverse:
theDACisfinebuttheADCtooksamplesatthewrongtime.Theeffectismuchthe
same.What’sworseinthiscaseisthatthenumberswe’verecordedarenowwrong.
InthepreviouscasewecouldslapinabetterDAC,withajitteryADCthegameis
over.
PLL’s
Converterchipsneedahighfrequencyclocksignal,usuallysomethingaround
22MHz.Itisalwaysmadebyalocaloscillator(anythingfromasimpleRCoscillator
inareceiverchiptoacrystaloscillator)regardlessofwhethertheunitisoperating
inmasterorslavemode.Thislocaloscillatorisindispensible:externalsyncsig-
nalsmaybeAES/EBU,asampleratefrequency“wordclock”orevenavideosignal,
neitherofwhichareofanydirectusetotheAD/DA.Instead,thelocaloscillatoris
speduporsloweddowntomakeitruninstepwith(“lockedto”)thesyncsignal.A
systemthatusesalocaloscillator“pulled”insyncwithanexternalsignaliscalled
aPhaseLockedLoop(PLL).A“phasedetector”comparesthelocalclockwiththe
JitterinAD(top)andDA(bottom)converters