Please correct me if I am wrong here but wasn't it proven by other pinsiders that the 3rd amp is for stereo sound, which x-files does not include stereo recordings in the roms. Or if it does maybe only one or 2 sounds? I did the research and considered this mod a few years ago and decided to go with the 2 speakers in the backbox split in mono and with the sub from pinball pro it's sounds great! I would be annoyed by only having the majority of sound in the left speaker after installing everything. I hope it works out well for you.

I was going to do something like this for SST. but if the roms are not programmed for it, it's just a waste of time. so I daisy chained 2 4" woofers for the backbox. L-paded it with the cabinet speaker. Made a world of difference. The screechy bugs were now much more tolerable. Ship animations would make the cabinet rubble. It was fantastic .

If you really want your x-files to pulsate, wire up some bass shakers along with the subwoofer. Otherworldly awesomeness.

This is a great question, because this game is mono, our speaker wiring harness and control are wired as such. The final two pins are un-used. So the Pinballpro.com control you have will continue to do what it was designed to do and that is to run MONO of of the one amp. Even after the upgrade. If you added the secondary amplifier, now the final two pins are being used. So you would now need to wire these up to a speaker, since they are open.

Unfortunately a mono (single channel) volume control will not work for a two channel application. You would instead need a stereo control. I build many custom things, in fact there is just too much to have everything on our website. If anyone does the upgrade to stereo on their X-files, we would need to building you a new wiring harness. Or if you order an X-files kit - we assume it is still factory, but can certainly building a custom set up for this application.

Greg @ Pinballpro.com