The See ColOr project aims at developing a mobility system for blind persons based on image color sonification. Within this project the present work addresses the optimal use of auditory-multi-touch interaction, and in particular the matter of the number of fingers needed for efficient exploration. To determine the actual significance of mono and multi-touch interaction onto the auditory feedback, a color matching memory game was implemented. Sounds of this game were generated by touching a tablet with one or two fingers. A group of 20 blindfolded users was tasked to find color matches into an image grid represented on the tablet by listening to their associated color-sound representation. Our results show that for an easy task aiming at matching few objects, the use of two fingers is moderately more efficient than the use of one finger. Whereas, against our intuition, this cannot be statistically confirmed in the case of similar tasks of increasing difficulty.