Grommets secure the top and bottom of the speaker.

Lift the speaker straight up and off its posts to remove it.

During reassembly:

Make sure the new speaker has grommets. If it doesn't, transfer over the original grommets.

Align the grommets over their screw posts and press down gently to secure the speaker in place.

Don't press down on the rectangular rubber diaphragm on the top edge, or you'll damage the speaker.