If you’re looking to connect a subwoofer to your car stereo without an amp, there are a few things you’ll need. The first is a subwoofer itself. You can find these in most stores, or you can order them online. The second is an audio amplifier. This will allow you to connect the subwoofer to your car’s audio system, and it will also provide power to the subwoofer. Finally, you’ll need some cables. These will allow you to connect the amplifier and the subwoofer together, as well as between the amplifier and your car’s speakers.