Speech synthesis based on the Multiband Resynthesis OverLap-Add (MBROLA) algorithm produces high quality speech without requiring too much effort to design the diphone database, and using a low computational power. The main drawback of this algorithm is the slightly metallic sound or buzziness that can be perceived on voiced segments. We are working on a speech synthesizer based on the MBROLA algorithm, and trying to improve its speech quality by means of on an enhanced phase control strategy.