Quoted from rapidflipper:I just purchased a 10” powered sub that really fills out the soundstage. I used alligator clips from the existing cabinet woofer, and ran the wires to the high-level input. There are a few benefits to this approach:
1. Easily removable when you sell.
2. It can be shared between two games! I also have a JJP GNR hooked up to the same sub.
https://www.parts-express.com/Dayton-Audio-SUB-1000-10-100-Watt-Powered-Subwoofer-300-628
I've done it exactly that way for the last 15 years. Works perfect.