Pre amp and Passive Speakers

[ozdennisb]

I understand how a notebook computer can amplify backing tracks through a passive speaker with sufficient clarity and volume in a venue that can accommodate some 200 people seated. However, I am unsure regarding the addition of vocals through a Shure SM58 dynamic mic. My query is whether the phantom power from a Xenyx 802 premium 8 input 2 bus British EQs mixer is adequate for this purpose, or do I need another preamp? In either case, can the two output signals from mic and notebook be connected through one input port in the speaker, or is it better/necessary to input the two signals through separate ports? I ask through ignorance as is obvious. All help gratefully received and acknowledged