Computer games, especially Massively Multiplayer Online Role Playing Games, have elements where communication between players is of great need. This communication is generally conducted through in-game text chats, in-game voice chats or external voice programs. In-game voice chats can be constructed to work in a similar way as talking does in real life. When someone talks, anyone close enough to that person can hear what is said, with a volume depending on distance. This is called positional or spatial voice chat in games. This differs from the commonly implemented voice chat where participants in conversations are statically defined by a team or group belonging. Positional voice chat has been around for quite some time in games and it seems to be of interest for a lot of users, despite this, it is still not very common.

This thesis investigates impacts of implementing a positional voice chat in the existing MMORPG Mortal Online by Star Vault. How is it built, what are the costs, how many users can it support and what do the users think of it? These are some of the questions answered within this project.

The design science research method has been selected as scientific method. A product in form of a positional voice chat library has been constructed. This library has been integrated into the existing game engine and its usage has been evaluated by the game’s end users.

Results show a positional voice system that in theory supports up to 12500 simultaneous users can be built from scratch and be patched into an existing game in less than 600 man-hours. The system needs third-party libraries for threading, audio input/output, audio compression, network communication and mathematics. All libraries used in the project are free for use in commercial products and do not demand code using them become open source.

Based on a survey taken by more than 200 users, the product received good ratings on Quality of Experience and most users think having a positional voice chat in a game like Mortal Online is important. Results show a trend of young and less experienced users giving the highest average ratings on quality, usefulness and importance of the positional voice chat, suggesting it may be a good tool to attract new players to a game.