There is a great need for better voice quality in text-to-speech systems. Today, only mechanically sounding male voices can be produced. The lack of success in producing a better sounding voice quality has been due mainly to a lack of knowledge of the voice source. We have also needed a good voice source model and an implementation of such a source in a text-to-speech system. The LF-model for the voice source has given us a tool for a description of the voice source dynamics in speech. The implementation of this source model in our text-to-speech system raises opportunities for synthesis with better voice quality and with different voices. In this paper the work on a female voice is described. The voice source dynamics in sentences and in different stress environments are studied. Acoustic parameters for a female reference speaker are compared to the male synthetic voice. These data are compiled into rules for synthesis and the results of these rules will be played at the conference.