Speaking as an American viewer, I must respectfully disagree ... it's rather easy, in fact, to determine that the voice actors in the Nelvana series are Canadian, because of certain vowel sounds particular to English spoken in regions of that country, and yes, the ever popular "oo" in place of "ow" (as in "aboot" for "about", though not quite so cliche-broad) is among them.
Also, I must admit, if one has a fondness for ubiquitous (that is, ever-working) Canadian actors, some of the names are familiar. Wayne Robson, who does Calculus, for example, has been seen in the US on many American shows filmed in Canada. (I remember first seeing him on the J. Michael Straczynski-run syndicated 3rd season of the 1980s TWILIGHT ZONE in the episode "Crazy as a Soup Sandwich", scripted by Harlan Ellison. He had the lead, but the star player was Tony Franciosa.)
And I must admit to simply adoring Tintin's English-language voice upon first hearing -- it almost precisely matched the voice in my inner ear. Even if some of the line-readings were too broad, I thought the persona and pitch were dead on. (The broadness, by the way, is due not to the actor, but to the voice direction, which ranges from only-adequate to abysmal, IMHO. It spreads to most of the performances [which is how you can tell the fault lies with the voice director], and is at its most offensive with the outrageously grating, even condescending overplaying of General Alcazar.)
Colin O'Meara's Tintin voice in the Nelvana series reminded me (pleasantly) of Larry Harmon, in the "American" English Belvision cartoons I watched as a kid. Tell the truth, the Nelvana voice that took me a LONG time to get used to was David Fox as Captain Haddock. I think as an actor he does a perfectly competent job, but the timbre seems just too high for a gruff old salt. Speaking musically, Fox is a tenor, and Haddock has always struck me as a baritone. Of course, I must admit, the first Haddock voice I ever heard was that of the amazing Paul Frees (who did all the voices EXCEPT Tintin and Snowy for the Belvision dubs), who did it nice and deep. Most of you might know Frees as the voice of Boris Badenov in ROCKY AND BULLWINKLE, or Meowrice the Money Cat in the film GAY PURR-EE.
However -- I have since heard the most perfect Haddock -- EVER. If any of you have the Netherlands cast album of the musical (not the Belgian cast, singin' in French -- the original Dutch cast, under the title KUIFJE: DE ZONNETEMPEL), check out Henk Poort. (I recently saw the show on tape -- it was recorded for Netherlands television by Canal + -- and Poort is absolutely as amazing as he sounds. If you're not inclined to buy the CD, go to the musical website --
www.musicaltintin.com or
www.musicalkuifje.com -- and check out the sample audios from the Netherlands side.