An in depth look at the way audio is transmitted for remote sports broadcasting. Topics include stereo, 5.1, Immersive Audio, and network specific configurations.

1. Unraveling The Complexities Of Audio Transmission For Sports Broadcasting
Courtesy: Calrec
As a Freelance TechManager/OpsProducer,it’salwaysabitof a rush to openthe email,andsee the
OpsMemo or Tech bookfor the upcomingshow.Inevitably,myeye alwaysgoestoone thingfirst…and
it’snot the camera complement,transmissionsheet,orthe mobile unitwe’re in.Italwaysgoestothe
audiotransmission,andwhat’srequired.Why?Because untilmostrecently, it’salwaysbeen mybiggest
weakness.
In an attemptto demystifyStems,LFE,BS&P, Sanitizedaudio, andsome otherthingsyoumaynot have
heard, I wentdirectlytosome of the top A1’sin the country to get some clarification.
Let’sdive rightinand start withthe basic 5 camera basketball show uptothe FOXNFL SundayGame of
the Week.
Dependingonthe size of the show,andthe NetworkorRSN,there are multiple waysof mixingaudiofor
transmission.Butlet’sstartwithsome of the basicsfortransmission,andthatisthe audioSTEMS.

2. STEMS
Stemsare defined asa discrete orgroupedcollectionof audiosourcesmixedtogether,usuallybyone
person,tobe dealtwithdownstreamasone unit.A single stemmaybe deliveredinmono,stereo,orin
multiple tracksforsurroundsound. Whenwe thinkof STEMS in sports production, we generallylookto
the individual channelsthatmake upthe audiomix.Left,center,right,andnats.
Thisbringsus to our nextpartof audiotransmission…
BASIC MIXES
There are manydifferentwaystomix audiofora show.We’ll lookatthe basicsall the way up to a
Primetime game.
The basic mix fora showisa STEREO MIX. This incorporatesfourdiscrete STEMS:
Ch1-PGMStereoLeft
Ch2-PGMStereoRight
Ch3-Mono Mix (Sumof the PGM mix Leftand Right)
Ch4-Nats
Next,we move upone level toa 5.1 mix or commonlyknownas SurroundSound,which incorporatessix
discrete STEMS:
Ch1-FrontLeft
Ch2-FrontRight
Ch3-Center
Ch4-LFE (LowFrequencyEffects)
Ch5-LeftSurround
Ch6-RightSurround

3. Courtesy: dotmedia.com
The LFE Channel isa mix of available audiosourcesselected bythe A1. The LFE fallsinthe 3-120Hz
frequencyrange.The audioconsole inthe mobileunitextractsthisfrequencyfromthe selectedsources
and sendsthemoutfor transmission.Sourcesthatare generallyput tothe LFE are musiccuts, sound
froma SpotBox,soundfromgraphics systems,andselectedmicsdependinguponthe sport.
LFE is commonlyreferredto asthe .1 Channel or subwoofer.Itshouldbe notedthatthe there isa
difference betweenthe two.Tounderstand thisfurther,Dolbyhasputouta greatdescription of this,
and youcan read aboutit here:
https://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/38_LFE.pdf
It isimportantto note that ona higher-level Networkshow,these sixdiscreteSTEMS do not necessarily
have to reside onChannels1-6for transmission.
NETWORK SPECIFICTRANSMISSION CONFIGURATIONS
All Networkshave specificconfigurationstheyuse for audiotransmission.If yousee a Remote Traffic
Orderthat asks forsix channelsof audio thatisn’tyour traditional Stereoor5.1 mix,itmay look
somethinglikethis:
Ch1-SanitizedPGML/T
Ch2-SanitizedPGMR/T
Ch3-InternationalStereoLeft
Ch4-InternationalStereoRight
Ch5-Commercial PGML/T
Ch6-Commercial PGMR/T

4. In thisscenario,there are three distinctaudio configurations.
1. SanitizedreferstoProgramaudiowithnon-copyrightedmusicplayinggoingtocommercial
breaks,or musicthat isrolledduringatease or promo. Thiscan alsoinclude the announcers
minusedoutduringcommercial breaksandrehearsals.
2. International isthe feedof ALLsources,minusthe announcers.
3. Commercial referstothe Programaudiowith copyrighted musiccuts.Thisisthe traditional live
to air feed,orthe “overthe air” feed.
Remember,all Networksarrange theirrespective audiomixesdifferently.Whenindoubt,call the TOC!
OtherRemote Opsmemosor TechBooksmay specout audiotransmissionwitheightdiscrete channels.
Thiswouldbe a combinationof SurroundandStereo:
Ch1-FrontLeft
Ch2-FrontRight
Ch3-Center
Ch4-LFE (LowFrequencyEffects)
Ch5-LeftSurround
Ch6-RightSurround
Ch7-PGMStereoLeft
Ch8-PGMStereoRight
MIXING FOR 16 CHANNELS OF TRANSMISSION
The largestscale showson remote canhave up to 16 Channelsfortransmissiononmultipletransmission
paths. We’ve alreadylookedat 5.1 Surround,StereoEFXLeftand Right,InternationalMix,anda
SanitizedLeftandRightMix.Whenwe combine all of those combinations,that’stwelve channelsright
there. Now we needtotake intoaccount Deportes,andBS&P.
In some cases, a Deportesfeedwill be necessary foragame.Deportesisa Network’sSpanishlanguage
feed,andisa divisionof the mainNetwork.The Deportes transmissionpathwilluse aLeftand a Right
Stereomix. Generally speaking, thismix isthe fullgame mix withthe Deportesannouncers, alongwitha
genericmusicmix.
If you’re sittingathome watchinga game,and all of a suddenyoucan’thear the announcer
microphones,chancesare aloudor discernable enoughexpletivehasbeendetected,and someone has
manuallyswitchedovertoa feedwhere all youhearare crowd mics.Thisisthe BS&P (Broadcast
Standardsand Practices) channel onthe transmissionpathbacktothe TOC. At the TOC, the audiofor
everyshowismonitoredforthese scenarios.

5. So a broadcast witha transmissionof 16 audiochannelscouldlooksomethinglike this:
Ch1-SanitizedPGML/T
Ch2-SanitizedPGMR/T
Ch3-InternationalStereoLeft
Ch4-InternationalStereoRight
Ch5-Commercial PGML/T
Ch6-Commercial PGMR/T
Ch7- BS&PCrowd Left– Pre-Fade
Ch8-BS&PCrowdRight– Pre-Fade
Ch9-Left
Ch10-Right
Ch11-Center
Ch12-LFE
Ch13-LeftSurround
Ch14-RightSurround
Ch15-DeportesLeft
Ch16-DeportesRight
Here’sa linkthatdescribeswhatelse BS&Plooksforina show:
https://en.wikipedia.org/wiki/Broadcast_Standards_and_Practices
Andhere youcan findthe FCCguidelines: https://www.fcc.gov/consumers/guides/obscene-indecent-
and-profane-broadcasts

6. THE FUTURE IS NOW…ATMOS…IMMERSIVEAUDIO
FirstdeployedforbroadcastbyNBCon the openingandclosingceremoniesof the Rio2016 Olympics,
Atmosisthe nextgeneration audioplatform.DevelopedbyDolby,itwasfirstinstalledinthe Dolby
Theatre inLos Angelesin2012. Immersive Audiotakesthe traditional 5.1mix,andupsthe experience by
adding4 additional overhead speakerstocreate a three-dimensional space witha5.1.4 mix.
Courtesy: Dolby
Atmosisseeninsome circlesas a complementto4KHDR broadcasts.Karl Malone, Directorof Sound
DesignforNBC,is a leadingauthorityonImmersive Audioforremote production.
https://www.sportsvideo.org/2018/02/20/live-from-pyeongchang-karl-malone-nbcs-director-of-sound-
design-on-the-2018-games/

7. You can read more here howNBCimplementedDolbyAtmosforNotre Dame football:
https://www.sportsvideo.org/2019/12/12/nbc-sports-caps-second-year-of-dolby-atmos-for-notre-
dame-football/
So nowwhenthe email arriveswiththe TechBookattached,andyou lookat youraudiotransmission
page,you’ll instantlyhave abetterunderstandingof all the possibleconfigurationsneededforyour
show.
Special thanks to:
FredAldous,FOXSportsAudioConsultant/SeniorNFLMixer
Jeff Cohen,A1forthe NFLon FOX
Steve Miller,A1forNBC,ESPN, FOX Sports
Karl Malone,Directorof SoundDesignforNBC