Happy Days: Tom Bosley's character of Howard Cunningham became this after the show began taping in front of a live, studio audience in 1975. Comparably quiet and somewhat distant in the early years, he became much more, well, loud in the later seasons.
Trigger Happy TV has the giant cellphone man who answers his ridiculously large phone and shouts into it as loud as possible, and does it in traditionally quiet places, such as a restaurant, or a movie theater, or an acapella concert, or even a book store.
Peter Boyd in Waking the Dead is surely one of the most obnoxious examples of the trope. Constant shouting is supposed to reinforce how mentally edgy the character is — if the police harassment, property damage and general violence haven't tipped you off already. Might be a case of Chewing the Scenery gone badly wrong... especially in later episodes, when every other regular character follows suit. The fact that they're always interrupting each other makes it even more frustrating.
Crazy Steve from Drake & Josh. Someone even once told him to use his indoor voice, and he continued shouting.
Zoey 101 had Coach Keller, who had few appearances but was always loud. At least once an episode, there will most likely be a sequence where the characters are obnoxiously shouting at each other, usually in the form of an argument.
Everybody on iCarly except for Freddie and Principal Franklin. Special mention goes to the cranky doorman Lewbert.
Victorious: Tori in the episode "Sleepover at Sikowitz's". "I AM A POLICE OFFICER!" And stuff like that. (Andre's grandmother, too.)
CBBC seems to have "must be audible from overhead aeroplanes" as a requirement for its presenters.
Timmy Mallet made a career out of this trope, in his case to increase his image of wackiness. Sometimes it worked, sometimes it just deeply irritated everyone who saw him. This was illustrated rather nicely in an episode of Room 101 where one prop was a "scale of children's TV presenters" with the zones "Loud", "Very Loud", "Obnoxious", and finally "Timmy Mallet".
When Davros removed the genes for emotions and conscience from the Daleks, he must have also removed the ones enabling them to speak quietly. As a consequence, the Daleks, even in casual conversation, scream every word out.
The Doctor: Sealed inside your casing. Not feeling anything... ever. From birth to death, locked inside a cold metal cage. Completely alone. And that explains your voice! No wonder you scream.
Azal, in the Third Doctor serial "The Daemons". For once, the effect is awesome. Partly justified by the fact that he's a 30-ft tall megalomaniac.
The Tenth Doctor isn't immune to this trope; he does have an indoor voice, but he seems to forget this a lot.
The Captain from "The Pirate Planet". Even the Doctor called him on that:
The Doctor: What do you want? You don't want to take over the universe, do you? No... you wouldn't know what to do with it, beyond shout at it.
24. JACK BAUER DEMANDS TO KNOW WHO THE TRAITOR IS AND WHERE YOU'VE HIDDEN THE PLANS. When he's not dramatically whispering, that is.
As Entertainment Weekly put it whilst discussing Kid Nation, "MY NAME IS JONATHAN KARSH! I YELL LOUDER THAN ANY OTHER HOST IN REALITY SHOW HISTORY!"
Bob Fossil in The Mighty Boosh yells (and yells nonsense) at least 90% of the time he's onscreen (of the remaining screen time, 8% is spent dancing).
The Supernatural boys have no concept of this. Perhaps they learned it from their father?
The army instructor in 'The Meaning of Life'. "DON'T STAND THERE GAWPIN'! LIKE YOU'VE NEVER SEEN THE HAND O' GOD BEFORE!"
As well as this instance from the skit "Interesting People":
David: ... With me now is Mr. Ken Dove, the most interesting man in Dotking. Mr. Dove, I do believe you're interested in shouting. Mr. Dove: YEAH THAT'S RIGHT DAVID! I'M VERY INTERESTED IN SHOUTING ALRIGHT! I THINK SHOUTING IS WONDERFUL! David: What does your wife think about it? Mrs. Dove: I AGREE WITH HIM!
NOBODY EXPECTS THE SPANISH INQUISITION!
The writers of All That apparently thought that if you couldn't think of a joke, just have a character act loud and obnoxious. Ms. Hushbaum in particular. The fact that she was a rather noisy librarian in addition to enforcing the rules by constantly screaming at the top of her lungs made her an example of Hypocritical Humor. Not to mention Billy Fucco.
Dustin Hoffman in the TV movie version of Death of a Salesman. He starts at about 7 or 8, cranks it up to 11 in the first five minutes and then never backs down a peg. It makes the whole play Dustin Hoffman SHOUTING AT THE TOP OF HIS LUNGS! YOU CAN'T EAT THE ORANGE AND THROW THE PEEL AWAY!!!! A MAN IS NOT A PIECE OF FRUIT!!!! It gets tiring.
FBI Agent Gordon Cole — played by David Lynch himself — in Twin Peaks is nearly deaf and yells nearly every line of dialogue. Combined with his Cloudcuckoolander personality, this makes for one odd character.
One of Will Ferrell's recurring characters on was Jacob Silge, a correspondent on Weekend Update who suffered from "Voice Immodulation Syndrome", which caused him to speak in a uniformly loud voice.
Inverted for laughs with the character "Man Without a Shout" played by John Goodman. A fake television series where the main character feels so guilty of killing his friends by triggering an avalanche that he is incapable of anything higher than a hushed whisper. He constantly gets placed in situations where he is required to scream and fails to do so.
Frasier: Chopper Dave got a little too used to reporting from a helicopter.
Played for laughs on Chappelle's Show, when Dave does his "Samuel Jackson Beer" sketch. He spends the entirety of it pretending to be Jackson and shouting his lines at people, which he acknowledges that he does.
Consumer: Could you stop yelling at me, please? Chappelle: NO, I CAN'T STOP YELLING, 'CAUSE THAT'S HOW I TALK! AIN'T YOU NEVER SEEN MY MOVIES? DEEP BLUE SEA? THEY ATE ME! A F*** ING SHARK ATE ME! JURASSIC PARK?
Ty Pennington, on Extreme Makeover: Home Edition. Not only does the man usually forget he has an indoor voice, but the producers decided to give him a loud-hailer, like police use in crowd control, as a gimmick.
On Parks and Recreation, Andy Samberg's head park ranger is pretty much always yelling, much to the annoyance of the staff.
"LESLIE, HAVE YOU SEEN AVATAR? I NEVER SAW AVATAR. I WANTED TO READ THE BOOK FIRST, BUT THEN I REALIZED THERE'S NO BOOK VERSION OF AVATAR."
Mighty Morphin' Power Rangers has Jason Lee Scott, the first Red Ranger. He was pretty loud most of the time out of suit, but morphed, he shouted everything. The man was living evidence of why this trope works best mixed 1:1 with Captain Obvious.
Ahem. "AH, AFTER TEN THOUSAND YEARS I'M FREE! IT'S TIME TO CONQUER EARTH!"
Mad Money host Jim Cramer.
Jack McCoy on Law & Order, even during his version of "normal" speech. In the courtroom, he shouts for real. In the office, it's not always exactly shouting, but his normal speech is much more aggressive and loud than even the cops he works with; he sort of stays in "badgering" mode. Happens more in the later seasons before he's the D.A.
Dalton Rumba on Glee. Partially justified because he's deaf in one ear, but DAMN! SCARLET FEVER!!
Jeremy Brett's performance as Sherlock Holmes features ample amounts of this trope; Holmes is prone of shifting from near-whisper to shouting his lungs out at a moment's notice, sometimes accompanied by complete ignorance of furniture or other obstacles as he skips to meet his newest client, or Watson with some new clue at hand.
G4 TV's show That's Tough — because you know things are tough when EVERY WORD OF THE NARRATOR IS DELIVERED LIKE A JERRY BRUCKHEIMER MOVIE TRAILER FILLED WITH EXPLOSIONS! THAT'S TOUGH!!!
X-Play comedy character CRAZY CRAZY CRAZY CRAZY CRAAAAAAZY ADAM!!!
In On The Buses it seems every character uses their outdoor voices all the time, especially when the family is at home. I love the series but you can get ear fatigue.
Hard Gay is almost always shouting. Lampshaded in one episode when a clerk tells him to keep his voice down, and he responds, "NO VOLUME CONTROL, HOOO!"
Horrible Histories invokes this at various times. Most notably with the "I'M A SHOUTY MAN!" sketches which crop up in various episodes. Other notable sketches include one from S1E5 with Caligula "THINK YOU'RE BIGGER THAN ME?".
And the Historical Masterchef sketches. "That must be the LOUDEST CREATURE ON EARTH!" "It's one of them."
When longtime announcer Rod Roddy fell ill in the early 2000s, Paul Boland (formerly of the 1998 revival of Match Game) did a week of guest announcing. The staff asked him to tone down his delivery; he refused, and never set foot in studio 33 again.
Rod's successor, Rich Fields, started out with a reasonably pleasant voice, but quickly became much, much louder (not to mention increasingly high-pitched and shrill). His delivery of "Here it CAAAAAHMS! From the Bob Barker studio…" and "A NEW CAAAAAAAAAAH!!!!!" in particular received Memetic Mutation. And then there are the contestants...
Wheel of Fortune is sometimes known for having very loud contestants. Host Pat Sajak likes to lampshade this by asking said contestants to "speak up".
Richard Karn during his hosting tenure on Family Feud. He would always yell "I'M DOUBLING/TRIPLING THE POINTS!!" at the start of the Double and Triple rounds, "TWENTY THOUSAND DOLLARS!" during Fast Money, and in general displayed an utter lack of indoor voice.
One of Chyna's teachers in the Ant Farm episode "sciANTs fair". Actually part of the plot, it turns out.
Ghost Adventures' Zak Bagans has a voice that may be capable of literally waking up the dead.
Joe of Impractical Jokers does this in the very first White Castle challenge, screaming in the customer's face.
Joe from Season 14 of Big Brother US shouts a lot in the diary room. This is lampshaded hilariously by his wife and children, first when his wife STARTS FAKE SHOUTING, and when all his children tells him to STOP SHOUTING!
Dan Gheesling as well as Peter Brown from the Canadian version also shout a lot in the diary room.
On Sesame Street The wild-haired radio DJ, named Bushman Bill (Who introduces Didi O'Dey and the Dew-Drops in Be My D) talks very loud and over-excited. At least the song he is playing is kind of nice and catchy.
Sketch ComedyVaya semanita, aired on ETB (the Basque Country public television) featured several skits starring a character known as "El Voceras" ("The Loudmouth"), whose main trait was that he always spoke incredibly loud, which tended to result in uncomfortable situations.
El Voceras: I'M NOT SHOUTING! I JUST HAVE A STRONG VOICE!
Other two characters on the show, the pair of ravers known as El Jonan and El Txori, would often fall into this trope as well due to their hyperactive demeanor.