One of the areas we cover in the class at City College is character voices. We’ll spend about 3 weeks experimenting to see if you have what it takes to create and maintain a character “voice.” Here’s some inspiration!
The two charts on this page highlight the different characters that each actor portrays in The Simpsons and South Park. Look at the number of voices the key actors are doing. Watch an episode and study what the actors need to do to change the entire personality, pitch, tone and cadence. Most voice actors who end up making a living (or at least earning money) doing cartoon voices are very versatile. They can slip in and out of convincing accents and dialects without missing a beat. They can age their voices. They can evolve a character into a new character with a few little tweaks. A few of the actors only do a few voices. In some cases this may be due to the fact that their voice has some unique quality that makes it hard for them to have as much versatility.
Dan Castellaneta, Hank Azaria and Harry Shearer carry the load in the Simpsons. They voice about 60% of all the voices in the show. Tress MacNeille and Pamela Hayden handle about a dozen characters each. The South Park cast is much smaller, so each of the key actors do even more voices. (See the link above for the South Park chart)
A big part of your job as an aspiring (or even as a working) voice actor is to study what other actors are doing. Listen, listen, listen. If you even have one tiny glimmer in your brain that you want to do cartoon voices, then you need to truly know if you have the ability to truly develop a convincing character (or 20!) and then hold onto it for the long haul.