Quoted from Chambo:I think the short answer to this is no. You would get sound from one pinnie drowning out the other
Go back a bit in this thread and you'll read some excellent suggestions on how to set up an external sub woofer. It seems easier to do on a JJP machine than a Stern machine, which in my case needed a kit
Wrong.
You can use several source on 1 subwoofer, and to preven any conflicting electric signal, you can use pinnovators:
https://pinnovators.myshopify.com/collections/all-other-systems-subwoofer-kits/products/pinsmx-passive-subwoofer-mixer
I have 4 pins (Metallica, Tron, Iron Maiden and AC/DC) connected to the same Polk PSW10, works like a charm !