So, whenever I plays a parakeet video, my bird, Flotsam, always fly over to the speaker to get closer to the sound. Apparently, she thinks the bird is trapped in the speaker. Is standing on top of the speaker bad for her? Will his make her ears go bad? And should I buy a male keet for her too?

No, as long as the speaker's not too loud, and she doesn't seem stressed out by it.

Parakeets respond to a lot of different bird calls, so your bird is hearing the sounds and responding to them. My bird used to do the same thing; he would hear the birds outside, and then respond by chirping like crazy.

He would also try to imitate sounds too, such as the beeping of our microwave oven, etc.

My parakeet does the same, except he just chirps in place. I would probably turn down the volume when your bird comes by the speakers since they have pretty sensitive hearing.
About buying a male mate for her: It really is up to you. How tame is your current budgie? Can you afford to support this extra bird in time and money?

Budgie owner.

Flotsam is just recognising flock sounds. It wont make her ears go bad, and its no reason to have to buy her a male BUDGIE either. Its seems Flotsam is tame so buying another budgie would make her bond to it and not you so not a good idea if you want a tame budgie.

Have 400 show budgies

My budgie did the same, except with his shiny reflective bell. He used to MATE with it! Then I got him a female, who chucked him to the bottom of the cage when he tried to mate with her, so hes gone back to the toys.......... Ahwell:)