Speeding up voice for self-voicing games.

Hi all.

Is there any way to speed up the voice in self-voicing games, e.g. Onslaught? I assumed they use the system voice, which I have set at a fairly decent speed. But if they are, they're ignoring my setting. It sounds like it's on the slowest rate setting. I'd like to get it closer at least to the speed I normally use with Voiceover, because the transition back to it is a little jarring.