There was a time when we enjoyed our favorite cartoons but didn’t think much about the people who spoke for them. These days, thanks to Comic-Con, people are able to say “I Know That Voice” and connect the actor with the voice.

John DiMaggio, best known as the voice of Jake on Adventure Time and Bender on Futurama, decided to help produce a movie to show people what his job is like.

The movie really provides a lot of insight into the job, and how it’s more than just reading aloud. For example, it shows voice actors have been around for decades, from animated shorts to radio, then Saturday morning cartoons, movies and now video games. It shows that voice acting can be just like regular acting in some ways, and can get physical. As a couple of artists demonstrate, doing a voice can also be just like singing.

There’s also the challenge of taking over a well-known character, whether it’s Fred Flintstone or Bugs Bunny, or finding the perfect voice for a new cartoon character. The movie does a fine job showing how actors approach these challenges

Tom Kenny (Spongebob and the Ice King from Adventure Time) also says voice acting is different than regular acting because they have to sound different than who they really are. There’s plenty of examples that prove that point, like Dee Bradley Baker using his voice and a vase to recreate the sound of a very big pig. Kevin Conroy, best known for Batman: The Animated Series, talks about how he helped cook meals for first responders after 9/11. He was recognized by a volunteer who was also an architect, who later asked him, “What’s it feel like to be Santa Claus?”

The list of interviews is very impressive. Aside from well-known voice actors like DiMaggio, Conroy, Grey DiLisle, Nancy Cartwright, Hank Azaria, Billy West and E.G. Daily, we also see Ed Asner, Marion Ross (Mrs. Cunningham on Happy Days, and now Spongebob’s grandma), Mark Hamill and SNL legend Laraine Newman.

Part of the film devotes a lot of time to Mel Blanc, the first great cartoon voice. It includes an interesting story about how his characters literally helped him recover from a near-fatal car crash in 1962. There’s also features about older artists including Stan Freberg, Janet Waldo and June Foray, who won an Emmy for her voice performance two years ago at 95 years young.

Family Guy by using an unusual voice, and how he learned how to be a voice director when he moved on to Robot Chicken.

It also shows how voicing for video games may be the most difficult of all. As one actor points out, scripts are much longer because actors have to act out dozens of results, not just one story line.

For the most part, voice actors stay anonymous, but the movie shows them at Comic-Con and other conventions, and how they’re treated like rock stars. The movie also shows how the internet has helped people create their own cartoons, and opportunities to become voice actors.

It’s also the only chance where you can hear “All the world’s a stage,” and Ezekiel 25:17, made famous in Pulp Fiction, in a very different way.

I Know That Voice is a fine tribute to the people behind the voices. They may be more well-known these days compared to 30 years ago, but it will also be enjoyable for those who’ve never seen them before, or know what they do.

P.S. There’s a special cameo at the end.

I Know That Voice will be available on demand, including iTunes, Amazon Video and cable outlets starting Tuesday, January 7.  For some clips and more information, go to iknowthatvoice.com