The Sony DAV-X1 system is a 2.1-speaker system, consisting of a subwoofer and a pair of speakers. It's designed for easy hookup by the user, with special speaker connection plugs and input jacks that are unique to the system. Because of this, you'll have to do some wire cutting if you want to change the speakers in the DAV-X1. But if you're willing to do this, you can succeed in your goal.
Grasp the connector on the back of one of the Sony DAV-X1 speakers. Pull the connector off the speaker with a firm pull.
Grasp the connector on the back of the other Sony DAV-X1 speaker. Pull the connector off the speaker with a firm pull.
Cut the wires leading to the connectors 2 inches behind each connector with a set of wire cutters.
Pull the two leads of each speaker wire apart for a distance of about 2 inches with your fingers.
Insert each lead, one at a time, into the wire strippers and remove a half-inch of insulation from the ends of each lead.
Connect the bare ends of the speaker wire leads to the terminals of your new speakers.