It is a common phenomenon for students to listen to background music while studying. However, there are mixed and inconclusive findings in the literature, leaving it unclear whether and in which circumstances background music can facilitate or hinder learning. This paper reports a study investigating the effects of five different types of background audio (four types of music and one environmental sound) on reading comprehension. An experiment was conducted with 33 graduate students, where a series of cognitive, metacognitive, affective variables and physiological signals were collected and analyzed. Preliminary results show that there were differences on these variables across different music types. This study contributes to the understanding and optimizing of background music for facilitating learning.