This study explores the differential effects of medium of delivery of aural input during listening tasks on learners noticing and type of comprehension (top-down and bottom-up) of Spanish object pronouns during focus on form listening tasks. Twenty-two college students enrolled in second year Spanish in a technology-enhanced classroom participated in the study. Two types of medium of delivery of input were compared: mobile assisted language learning (MALL), which is learner manipulated, and instructor manipulated language learning (IMLL). A quasi-experimental design was used -- treatment and immediate tests -- in order to measure participants' reported noticing and type of comprehension. Noticing was operationalized using think-aloud protocols, and measured on the post-test exposure comprehension assessment tasks. The findings of the study, interpreted within the attentional SLA framework, indicate that learners in the MALL group demonstrated significantly higher levels of reported noticing, bottom-up comprehension, and top-down overall comprehension than learners in the IMLL group. Directions for future research as well as pedagogical implications of the use of mobile technology and task-based listening activities are offered.