Speaker Wire

I have a Edifier S330D subwoofer with an inbuilt amplifier. The subwoofer does only have speaker outputs for 1 speaker. It connects with speaker wire. Would it be possible (and safe) to plug both two speakers into only one port? I was thinking that maybe I could plug two wires in all the ports...

Have vintage rack audio system with speaker wire outputs to stereo. Passive speakers. Want to record my vinyl collection to CD. How do I interface the speaker wire connectors to the laptop's USB? Understand some adapter may be needed - will appreciate pointers and URLs. I know a USB turntable...

I got a new sound bar for Christmas, and wanted to hook it up to an old set of speakers and a receiver that I had. I want to at least hook it all up to my PC, and possibly the bluetooth if it works through all speakers. This is what I have to work with: Vizio Soundbar w/ bluetooth (can't find...