Quoted from MightyGrave:
Thats a cool idea - can you explain how it works ? And have you trouble if all games running at the same time?
Here's the device that converts the woofer outputs to a low level, isolated signal for a mixer. Plenty of other similar devices, but these are inexpensive and work fine. I installed insulated alligator clips to make it easy to hook up to the internal woofer (on non-AP pins). Output is RCA, which I simply run under the pin's woofer (protected so it doesn't get crushed) to the bottom of the cabinet.
I originally had a 4 channel mixer, but moved to a 6 channel later on. The mixer's output then goes to the active subs. I just used a RCA 'Y' splitter to get the 2 outputs for the subs.
You really don't need much for a sub to make a big difference, and a couple of 8" subs sound great. With 6 pins in that row, I did feel I needed two subs otherwise the bass seems distant. I originally tried my 12" sub from my AV setup, but it was a bit much.
To clean up the cable mess, I installed a cheap, plastic 'cable run' right above the baseboard to hide the wires that end in Keystone RCA jacks, then short cables to go from the Keystone jacks to the mixer. I also have RCA plugs on the cable run so I can disconnect a pin if needed. Very clean install. Prior, all the wires on the floor behind the pins drove me nuts.
People have asked me about having all six pins being played at once. Can't answer that since it's really just me and the spouse playing - so only one pin is being played at a time. But there should't be an issue tho, other than maybe adjusting the levels so you don't overdrive the sub's amp. In my case, I could have had a sub for 3 pins, but I prefer to have two subs going since it really fills up the room with nice bass. We've had company over where 2 or 3 were being played at once, really didn't notice any issues.