||The paradigm of product selection on Web stores was used to investigate the psychological and physiological responses of participants of both genders to background sound effects over the Internet. The purposes of this research were to determine whether music, voice cues, and earcons (i.e. non-music, non-verbal audio messages) can influence the level of shopping time, individual time perception, heart rate elevation and rated emotional responses when shopping on two different business-to-consumer (B2C) Web stores. One of those stores sells gifts and the other sells mobile phones. In the first experiment, results of 96 participants indicated that on the Web store selling gifts, music showed significantly positive effects only on male participants (p<0.05), while earcons significantly increased levels of pleasure with only female participants (p<0.05). Similar results were not found on the mobile phone Web store. Results also indicated the effects of music, voice, earcons and gender had significant interactions with one another ( p<0.05) . A second experiment using think-aloud technique was conducted to explore possible reasons for the significant interactions between the effect of music and the type of Web stores with male participants. Results showed that male participants spent more percentages of time in examining the appearance of products on the gift Web store and than on the mobile phone Web store (p<0.001). On the other hand, male participants spent significantly more percentages of time in examining the functions of products on the mobile phone Web store than on the gift Web store (p<0.001). Together with the results of open questions, possible generic reasons for the differential effects of music on the two Web stores were suggested. Potential and actual applications of this research include the design of commercial Web stores and other Web-based services.