Ultrasound characterization of biological tissues is facing the challenge of accurate sound velocity determination in soft materials of poorly controlled shape. In this work, an original method based on a through-transmission configuration is proposed to accurately determine the sound velocity cs in non-parallel bio-mimetic specimens. To account for the possible lack of parallelism of the specimen, a set of 8 geometrical parameters is introduced. In a three-step process, the transducer spacing and mis-orientation are deduced from a pair of reference echoes with no specimen in the burst path. Then, main and intermediate echoes in presence of the specimen are processed to yield the characteristic distances of the through-transmission configuration. Finally, the orientations of the specimen faces are determined through a minimization algorithm. Once the system geometry is fully determined, the specimen sound velocity is obtained. A scan of the specimen along the acoustic path (Z-scan) provides the necessary information to completely determine the equation set. The proposed method has been applied to determine the sound velocity in oil-in-gel emulsions as well as in their pure constituents. It is expected that the above method could provide accurate sound velocity data for a better understanding of complex material acoustic response to achieve a more efficient biological tissues characterization.