Using the Engines/Voices TAB, you can select the voices you like, as well as edit their pitch and speed so that they sound better.
If you want to add more voices, visit the
More Voices Page.
Click on individual voices and click the Test button to hear a sample of the voice. If you like the voice, click enable. If you don't want this one used, click Disable. If you would like to change the pitch or speed of a voice, click the Edit button, and you'll be able to adjust them. As you get more comfortable with listening to computer generated voices, you may want to speed up the reading in order to get information faster and shrink the size of the files.