[zebproj]

Not directly, no. IIRC, programs like Espeak and Festival use formant synthesis, which would require explicit formant values. Voc models the tract itself... the main parameters are diameters in the vocal tract (which implicitly produce vowel sounds).

It may be possible to go the other way around and analytically derive parameters for Voc that match target formant frequencies. Not sure though...

[marmaduke]

There are other ways though e.g. if features like formants produced by the model can be differentiated with respect to vocal tract parameters, the latter could be estimated based on real data maybe