Video game voice-chat provider Vivox is announcing today that it has raised $6.8 million for its business of providing voice services for online games, virtual worlds and social networks.

Vivox ustomers include CCP Games, Electronic Arts, Gaia Online, Hi-Rez Studios, Linden Lab, NCsoft, Nexon, Realtime Worlds, Sony Online Entertainment and Wizards of the Coast. While others provide voice-over-Internet-protocol voice services in games, Vivox focuses on providing a managed service.

With Vivox, you can make your voice sound like a monster or a 12-year-old kid. The sound is also directional, allowing you to figure out which direction someone is shooting from in an online game. Sony Online Entertainment is using it in its existing games, including “EverQuest,” “EverQuest II” and “Star Wars Galaxies.” Sony will also use Vivox in future MMOs such as “DC Universe” and “The Agency.

The Natick, Mass.-based company has huge momentum behind its business with 20 million users per month across 180 countries. It already delivers billions of minutes of voice per month, said Rob Seaver, founder and chief executive of the company. He said Vivox will use the new funds to accelerate its growth. “We’re in the bullseye of the fastest growing markets,” Seaver said.

IDG Ventures led the round with follow-on investment from Benchmark Capital, Canaan Partners and GrandBanks Capital.

One of the company’s newest services is a voice chat app for Facebook. Phil Sanderson, managing director of IDG Ventures San Francisco, said his company invested because voice is becoming a critical component in virtual worlds and online games, which are becoming increasingly social with the rise of social networks.

Vivox makes money through licenses to its business partners, voice-based advertising and voice-based virtual goods. The company was founded in 2005 as an idea born from the Jeff Pulver Group, owned by voice visionary Jeff Pulver. It has 35 employees. Its rivals include Dolby, Skype, Teamspeak and Ventrilo. To date, the company has raised $21 million in three rounds.