Crown CM-30 User guide

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7/00
Crown International, Inc
P.O. Box 1000, Elkhart, Indiana 46515-1000
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reserved PZM®, PCC®, SASS®and
DIFFEROID®,areregisteredtrademarksof
CrownInternational,Inc.Alsoexported
as Amcron®

vibrations,butitdoeshearfootstepsacoustically,like
yourears.Normallythis isnotaproblembecausethe
audienceseesandhearstheactorswalkingacrossthe
stage.
ThePCC-160picksupsoundfromthefront,butitrejects
soundfromtherear.Thatis,itpicksuptheactors,butnot
muchofthepitorchestraorP.A.speakers.Also,thePCC-
160rejectsfeedback.ItwillfeedbackifthePAistooloud,
likeanymic,butyoucanturnituplouderwithout
feedbackthanmostothermics.
Tofurtherrejectthepitorchestra,placethePCC-160in
asmallL-shapedcornermadeofthin cardboard
(Figure2).Orlayapadofacoustic foamonthefloor
behindthemicrophone(2"to4"thickby1foot
square).
Inuse,thePCC-160is nearlyinvisible,soit doesnot
distractfromtheset.Itreducesstagefright.Young
actorstalkmorenaturallybecausethey’renottalking
intoamicrophone.
How doyouusethem?Typicallyyouevenlyspacethree
PCC’sneartheedgeofthestage(Figure3).Placethem
ascloseaspossibletowardtheactors.OneortwoPCCs
mightbeenoughforasmallstage.
Themoremicsthatareon,themuddierthesound,and
themorefeedbackyouwillhave.Toaidclarityand
reducefeedback,turnupasfew micsaspossible.For
example,supposeanactorwalksacrossthestagefrom
lefttorightwhiletalking.Firstturnupjusttheleftmic,
thenturnitdownwhileturningupthecentermic.
Thenturnit downwhileturninguptherightmic.
Follow cuesin thescriptsoyouknow whentoturnup
variousmicrophones.
Whenyoudosoundreinforcementforspeech,you
wantthesoundtobeclear,natural,andloudenoughfor
everyonetohear.High-qualitymicrophoneswillhelp
youreachthis goal.Inthis guide,we’lloffermikingtips
forfiveapplicationsinspeechreinforcement:stage,
lectern,conference,courtroom,andathleticevents.
We’llsuggestwhichmicrophoneis bestforthejob,and
wheretoplaceit.
Whenyouputtogetherasoundsystem,onegoalisto
minimizefeedback.This isthesquealingsoundyou
hearwhenthemicspickuptheP.A.speakers.Most
Crownmicrophonesaredesignedtorejectfeedback,
soyoucanturnthemuploudenoughforeveryoneto
hear.
Also,Crownmicsaredesignedforclear,cleansound
sothatspeechwillbeeasytounderstand.Crownmics
soundnaturalandtrue-to-life,ratherthan“canned”or
muffled.
Besidesgoodmics,it’simportanttousehigh-quality
speakers.Placethemasclosetotheaudienceasis
practical,aimingattheaudience.Nomic soundsgood
throughapoorlylocatedspeakersystem.
Let’slookatavarietyofaudiosetups.Ineachcase,we’ll
suggesthow tochoosetherightmic andhow touseit
effectively.
THEATERSTAGE
Playsandmusicalsin anauditoriumarearealchallenge
topickupandamplifywell.First,trytosolvethe
problematitssource.Thedirectorshouldaskthe
performerstospeakloudlyandclearly.Ifthemusic
drownsouttheactors,youmighttactfullyaskthe
musicaldirectortohavethepitorchestraplaymore
quietly.
Goodmicrophonescanhelp,too.Threetypesof
microphonesforstagemikingarefloormics,hanging
mics,andminiaturewirelessmics.
FloorMics
The Crown PCC-160 is a stage-floor microphone for
mikingdrama (Figure 1).Youplace it on thestage floor,
near the footlights.It’s the industry-standard stage mic
onBroadway,and has beenextensively field-tested in
schools.
The PCC-160 sounds clear and natural,and can be
turned uploud enoughfor everyone to hear the
performance and understand the words.It’s rugged
enough to withstand kicksby dancersand can be
stepped on withoutdamage.
You might wonder if the mic picks upfootsteps,since
it’s on the floor.The PCC-160 is not sensitive to floor
Figure 1 – PCC-160 supercardioid surface-mount microphone.
Figure 2 – Two methods to improve rear rejection of PCC-160.

Stage—HangingMics
TypicallythePCC-160can“reach”about30feet.Butifyou
havetroublehearingactorsfartherupstage,hangoneto
threemicsnearthem.Themoremics,themorefeedback
potentialthereis,however.
Crownmakesaminiaturehangingmicrophonecalledthe
CM-31(Figure4).Itsoundsclearandnatural.Themic
picksupfromthefrontandrejectssoundfromtherear,
whichhelpsrejectfeedback.Youhangitfromtheceiling.
TheCM-31comesintwoparts-microphoneandtubular
electronicsmodule,whichyouplugintoamiccable.In
anotherCrownmodel,theCM-30,theelectronicsmodule
mountsinastandardelectricaloutletbox.
Stage—MiniWirelessMics
Anotherwaytopickupthemainactorsonstageiswitha
miniaturelavalierwirelessmic. It's about asbig as asmall
paperclip.Youcanclipitonclothing(Figure5),orhangit
overtheactorsforehead with thecablerunning through
thehair.Topreventsweat damage, youmightwant to cover
themicinathinplastic sandwich bagorplastic wrap.
Plugthemicintoabelt-pack transmitter ofyourchoice.
Sincethemicisveryclosetotheactor,thesoundislouder
andclearerthanyougetwithafloormic.Ifbudgetpermits,
useminiwirelessmicsforthemainactors,andPCC-160
floormicsforgrouppickup.
Whenyouuseawirelessmic,putthereceiveronstageand
runacablebacktoyourmixer.Thiskeepsthepathshort
betweenthetransmitterandreceiver,preventingdropouts
andnoise.Ifyouwanttomonitorthereceiver’sperfor-
mance,putitbackatthemixer.Butmakesurethetrans-
mitterhasalineofsighttothereceiver.
Alwaysusehigh-qualityalkalinebatteriesinthetransmit-
terandchangethembeforeeachperformance.
Adjusttheaudiotrimpotinthetransmitterashighas
possiblewithoutanydistortionorclipping.Here’show:
1.Turnuptheaudiotrimpotalltheway(fullclockwise).
2.Havesomeonetalkloudlywhiletransmittingoverthe
wirelessmic.
3.Listentothereproducedsound.Ifitsoundsgrittyor
fuzzy,itisdistorted.Turndownthetrimpotalittleata
timeuntilthedistortionstops.Note:Useaplasticscrew-
drivertoavoiddetuningthetransmitter.
UsinganEqualizertoPrevent
Feedback
Aneffectivewaytoreducefeedbackistouseathird-octave
graphicequalizer(Figure6).Thisisanelectronicdevice
witharowofknobs.Eachknobcontrolsaspecificband
of frequencies.Theknobstowardtheleftcontrolthelow
frequenciesorbass,whiletheknobstowardtheright
controlthehighfrequenciesortreble.
Here’showto usethegraphicequalizer.Connectit
betweenyourmixeroutputandpower-amplifierinput.
Startwithallthecontrolsattheircenteror“flat”position.
Turnthemixer’smastervolumecontrolsabout3
⁄4up
(to0,ortheshadedportionoffadertravel).Onthemixer,
slowlyturnupthevolumecontrol(fader)foronemicro-
phoneuntilthesoundsystemstartstoringorfeedback.
Theringingwilloccuratacertainfrequencyornote.On
thegraphicequalizer,pushdowneachknobinturn,then
returnitto0orflat.You’llfindoneknobthatstopsthe
feedback.Pushitdownjusttothepointwherethe
ringingstops.
Nowturnupthemicalittlemoreonthemixeruntil
feedbackstartsagain.Itmightbeatadifferentfrequency.
Figure 3 – Stage miking with PCC-160 microphones.
Figure 4 – Upstage miking with CM-30/CM-31.
Figure5 –clip-on microphone.

Findtheequalizerknobthatreducesthefeedback,and
pushitdownuntiltheringingstops.Keeprepeatingthis
procedureuntil thesoundsystemis loudenough.
Therearedevicesavailablethatcontrolfeedback
automatically.Suchadevicedetectsfeedbackandthen
turnsdownthecorrectfrequencyallbyitself.Askyour
localCrowndealerfordetailsonthesedevices.
LECTERNS
Herearefourwaystopickupspeechesatalectern:
•Gooseneckmic
•Clip-onmini mic
•Surfacemountedmic
•Handheldmic onaboomstand
Let’slookateachone:
GooseneckMic
Agooseneckmicis alectern-mountedmicrophone
withanarm(gooseneck)thatpositionsthemic near
thepersonspeaking.TheLM-300Agooseneckmic has
aslim,elegantdesignthatdoesnotdetractfromthe
personspeaking.Itsdualgoosenecksadjustsilently.The
AtlasAD-11flange.Itscablecanexit downoroutthe
side.
Needextraruggedness?TrytheLM-201,whichhasa
ball-and-socketswivelinsteadofagooseneck(Figure
7).Theswiveloperatessilently.
Touseagooseneckmic,talkabout8"away,overthemic
topreventbreathpops(asin Figure7).
Lectern—Clip-onMiniMic
Ifthepersontalkingwandersaroundwhilespeaking,
you’llneedtoclipa miniaturemicontotheirclothing.
Figure5shows aCrownCM-10in thisapplication.
Lectern—Surface-mounted
DirectionalMic
Some micsaremadetobeplaceddirectlyonthelectern
surface.Theyalsoaredirectional,sotheyrejectsound
fromtherear,suchasfeedbackfromtheP.A.speakers.
Crownmakesthreemicsforthis purpose:ThePCC-
160,PCC-170,andPCC-130.Thesemicssound
almostthesame butlookdifferent:
•PCC-160is themostrugged
•PCC-130is stylishandsmal
•PCC-170is stylish,thoughlargerthanthePCC-130
Figure6– Graphicequalizer.
Figure7 –LM microphone on alectern.
Figure8 –PCCmicrophone on alectern.
microphoneplugsintoafemaleXLR-typechassis
mountconnectorin yourlectern,orit canbeinstalled
inanLM-SM shockmounttoreducelecternthumps.
Inthiscase,themic plugsintoafemaleXLRcable
connector.Anothermodel,theLM-300AL,is 3inches
longer.
ThemodelLM-301Ascrews ontoamic standoran
Laythemic ontopofthelecternasin Figure8.Since
themic isrelativelyfarfromthetalker,thetalkercan
movearoundmorewithoutgettingoff-mic.Thegain-
before-feedbackisnotasgoodaswithagooseneckmic
becausethePCCisfartherfromthetalkersotrythe
PCCin yoursystemfirstbeforesettlingonit.
Lectern—BoomMic
For a temporary setup,use a handheld micona boom
(Figure 9).Crown mics for this purpose are theCM-
700 orCM-200A.

OntheCM-700,setthemic switchtoBASS ROLLOFF.
Placethemicabout8"awayfromthetalker.Putthe
suppliedfoamwindscreenonthemic topreventbreath
pops.Topickupsomeonewhoisnotusingalectern,
placethemic onaregularmic stand(Figure10).
SupposeyouhaveatemporaryP.A.setup,suchasaschool
principaltalkingtoacrowdofpeoplesittinginbleachers.
ObtaintwoP.A.loudspeakers,eachcontainingoneortwo
woofersandahorn.PuttheP.A.speakersoneithersideof
themic,behindthemicandtowardtheaudience.The
speakerscangoeitheronthefloorangledup,orontop
ofspeakerstands(Figure11).
CONFERENCES
Suppose you need toreinforcespeech ata conference
table.You’ll useseveral microphonesfedinto a mixer.
This mixer can be either standard or automatic.An
automatic mixer (gated mixer) turns on a microphone
when someone speaks into it and turns off all the other
mics.This makesthe soundclearerand reduces feed-
back.
An automatic (gated) mixer also allows extra features
such as chairperson override,number-of-open-micro-
phones compensation,andsoon.
If you want to use a standard(non-gated) mixer,
each user needs tomanuallyswitch hisor her mic on
or off.
Chooseone of these switchable microphone models:
PCC-130SW:Smallmicwithahalf-cardioidpatern.
PCC-170SW:Largermicwithahalf-supercardioid
pattern forextra clarity.
PCC-170SWO:Like the PCC-170SW,but provides
remote sensing of switch closure.This mic canbe used
witha video camera switcher.Whena person turns on
their mic,the camera aiming at that person is switched
on.Then the TV-monitor view tracks whoever is
speaking.
MiniBoundaryMics: Very smallmics withahalf-
supercardioidpattern.Three switchable models are
available:
MB-1: Plugsintoanaluminumorbrassinsertinthetable.
MB-2: Plugs into a jack in the table.
MB-4E: Lowest cost.Cable fitsthrough a smallhole in
the table.
Thesesmodels require an MB-100 or MB-200 interface.
The MB-100 interface has connections for an on/off
switchnear each user.The MB-200 interface also
allows remote sensing of switchclosure,so it can be
used with a video switcher.
If you want to use an automatic (gated) mixer,
choose one of these mics:
PCC-130: Smallmic with a half-cardioid pattern.
PCC-170: Largermic witha half-supercardioid pattern
forextra clarity.
Figure 9 – CM-200ASW microphone at a lectern.
Figure 10 – CM-200A microphone on a mic stand.
Figure 11 – Temporary P.A. setup.

backrow.Ifyouprefertouseamic standinstead,usea
CM-700orCM-200Acardioid mic.Youcouldalsouse
aPCCtypemicrophoneonanearbysurface.
ATHLETICANNOUNCEMENTS
Forathleticevents,youneedamicthatpicksupthe
announcerwithoutpickingupthecrowdnoise.Thatis,
youneedanoisecancellingmic.Crown’snoicecancelling
micistheCM-310ADifferoid.Ithasthemostgain-
before-feedbackandisolationofanymicrophoneavailable.
Youcanturnitupveryloudwithoutfeedback.Sinceit
cancelssoundsafewinchesaway,themicmustbeused
withthelipsjusttouchingthegrille(Figure14).Youmight
prefertheCM-310ASW,whichhasanon/offswitch.
TheDifferoidisusedattheIndianapolis500Speedway.
Anannouncersitsinthestandswiththeaudience.Even
withthetrackspeakersblaringathim,thereisnofeedback.
Ifannouncersmovetheirhead tofollow thesportsaction,
youmightwanttouseaheadwornmic suchastheCrown
CM-312A.It’slightandcomfortable,andprovidesgood
volume withoutfeedback.Themic ismountedtotheside
ofthemouth.
Iffeedbackis abig problem,trytheCM-311Differoid
headwornmic (Figure15).It’splacedin frontofthe
mouth.ModelsCM-311AHSandCM-312AHSmount
onaSonyMDR-7506headphone.
MiniBoundarymics:Verysmallmicswithahalf-
supercardioidpattern.Fivemodelsavailable:
•MB-1:Plugsintoabrassoraluminuminsert
in thetable.
•MB-2:Plugsintoajackin thetable.
•MB-3:Tubular;mountsinceiling,wallortable.
•MB-4:Fortemporaryuse.Hasathin,cablewith
anXLRconnector.
•MB-4E:Lowestcost.Cablefitsthroughasmall
holein thetable.
ModelsMB-1,MB-2,andMB4ErequireanMB-100or
MB-200interface.TheMB-200interfacealsoallows
remotesensingofswitchclosure,soitcanbeusedwith
avideoswitcher.Eachinterfacecantakeuptofour
mics.
Forteleconferencingapplications,seetheCrown
MicrophoneApplication GuideForTeleconferencing
andDistance Learning.
COURTROOM
Here are suggestions formiking the people in acourt-
room.Please refer to Figure 13.
Judge: Place a PCC on the judicialbench.This is a
surface-mounted mic which rejects feedback.Three
models are available:
•PCC-130 is a small,inconspicouscardioid mic.
•PCC-170 is largerbutis supercardioid.
• PCC-170SW or PCC-130SW has an on/off
membrane switch.
If you want this microphone to pick upboth the judge
and people standingat the bench,use aCrown PZM-
30D,whichpicksupallaround.
Lawyer: If thelawyerwandersaroundwhilespeaking,
clipa CM-10 mini mic to their clothing about 8" under
the chin.If you preferto go wireless,use a CM-10E mic
into a wireless transmitter.If the lawyer speaks mostly
from a table,install aPCC of yourchoice on the table.
Witness: Installa Crown lectern mic such as the LM-
201,LM-300A,LM-300AL, or LM-301A.Use the
supplied foam windscreen.Another option is a PCC
surface-mounted mic of your choice.
Jury: Hang aCrownCM-30 or CM-31 microphone
over and in front of the jury.Place the mic 18" in front
of the front row,and 18" overthe head-height of the
Figure 12 – Miking a conference with PCC microphones.
Figure 13 – Courtroom miking.
Figure 14 – Proper use of a CM-310A Differoid microphone.

UNDERSTANDINGSPECS
We’ve covered how to choose and use Crown micro-
phones in various applications.Now let’s explain the
specs found inmicrophone data sheets.
Transducer Type or Element: This spec describes how
the mic converts sound into electricity.The three main
types are condenser,dynamic,and ribbon.All current
Crown mics are the condenser type,which generally
provide the highest sound quality.
Powering: Condenser micsneed apower supply to
operate.All Crown mics can be powered bya phantom
power supply,which provides powerto the mic along
the mic cable.Phantom power is 12to 48 volts DC on
pins 2 and 3 with respect to pin 1 of the mic-cable
connector.Most modern mixers have phantom power
built in.
If your mixer lacks phantompower,youcan usean
externalphantom supply made by Crown.Use either
the model PH-4B (4 channels,AC powered) ormodel
PH-1A(onechannel,batteryorACadapterpowered).
Model PH-4B is shown in Figure16.
Frequency response. This istherangeof frequencies
that themic reproduces at an equal level,usually within
a tolerance (such as +/- 3 dB).A frequencyresponse of
80 Hz to12 kHz isgood,60 Hz to 15kHz is better,and
40 Hz to 20 kHz is excellent.Note,however,that 80 Hz
to 12 kHz is morethan adequate forspeech.
Polar pattern. This spec describesthe directional
pickup pattern of a microphone —how it picks up
sounds fromvarious directions.Figure17 shows
various polar patterns.
An omnidirectional mic picksupsound equally well
from all directions.This pattern can causefeedback in a
P.A.system unless the mic is clipped onto the person
speaking.
Aunidirectional mic picks upsound best from one
direction—in front of the microphone.It reduces
sound pickup from the rear.The three main types of
unidirectional patterns arecardioid,supercardioid,and
hypercardioid.They have progressively more rejection
of sounds from the side.
Impedance: Thisis an electrical characteristic of a
microphone.All Crown microphones are low impedance
(lessthan600 ohms).This lets you run long mic cables
without picking uphumorlosing clarity.
Crown has other microphone application guides,free
from your Crown dealer or directly from Crown:
• Microphone Application Guide.Thiscoversmusic
recording andsound reinforcementfor CM,LM,and
GLM series microphones.
• Boundary Microphone ApplicationGuide.Thiscovers
boundarytheory and applications,teleconferencing,
musicandspeechrecordingandreinforcementforPZM,
PCCand SASS microphones.
• Microphone Application Guide for Video
• Microphone Application Guide for Houses
of Worship
• Microphone Application Guide for Schools
• Microphone Application Guide for Teleconferencing
and Distance Learning
• MicrophoneApplicationGuide for Security and
Surveillance
• Microphone Application Guide for Studio Recording
Wehopethisguidewillhelpyoureinforcespeechwitha
clear,naturalsound.Whateveryouraudioapplication,
Crownmakesamicrophonedesignedforit.
Figure 15 – CM-311A headworn microphone.
Figure 16 – PH-4B phantom power supply.
Figure 17 – Polar patterns.