I would think it would be best to disconnect the cabinet speaker if you are using an external sub. It would not only be redundant, but it could also potentially conflict with the sub and make everything sound worse.

I've left mine plugged in with no issues. (Guns n roses if that matters)

The stock cabinet speaker provides mid bass. unless you are redoing the backbox speakers, definitely leave it plugged in.

+1

Yea, I was looking at that exact sub yesterday. Let us know how it sounds when you get it connected! As far a hookup, that sub already has a crossover built it and it's adjustable, so I would think you'd want to connect the main speaker line to it and not the sub line. This would give the subwoofer the pin's full spectum and allow it's own crossover to do it's job as designed. Also, if you have a factory sub (or mid-range) I would disconnect that as well to eliminate possible phasing problems. 50/50 chance on that one. If it sounded like crap in conjunction with the existing sub just reverse polarty on the new sub. Some have a switch for that too. Good luck and let us know!

I ended up having a really nice sub (outlaw) laying around so it is now dedicated to the Lotr and T2. I think you want the cab speaker left in. I don't know about your particular sub but most have a phase switch on them. I beleave you want the midrange produced by your cabinet speaker. Just adjust the sub crossover to your liking. Think your really going to enjoy it.

Unless I'm mistaken, there is no additional stress on the pinball machine due to the fact that the new sub is "powered".

I agree with GoVols..shouldn't hurt a thing as you're using a powered sub and just getting the signal from the pin amp.

So leaving the existing speaker in, you run wires from where to where? Anyone have pictures?

I used alligator clips right on to the terminals on the cabinet mounted speaker. For my setup I made my own cable. Single RCA to the alligator clips on the pinside. I fed the wires through the grate underneath.

As long as the sub has speaker level inputs you can hook it straight to the cab speaker without any issues. Leave the cab speaker hooked up! Heck on my DM Williams was kind enough to leave an open set of male spade connections on the speaker terminal. Get you two of these and your good to go!

http://www.binbin.net/photos/generic/min/miniature-female-spade-connector-min-spade-female-.jpg

See the pic in the thread below that B_R posted. Its as easy as that.

http://pinside.com/pinball/forum/topic/external-sub-on-sterns-how-to-help-please

That's an interesting thread. There was some difference of opinion about the correct way to wire up a sub. So just to clarify, the general consensus is that it's perfectly safe to piggy back an external self-powered sub on to the cabinet speaker? If this is true, I'm going to do this on my AC/DC premium. I happen to have a powered sub with speaker level inputs lying around.

Thank you. Thanks to all for their help.

I didnt read all the different back and forth with respect to ACDC specifically as i dont have one but any/all i have done for stern/williams games of all eras i just connected with existing sub remaining and it has been awesome.

79 bucks at amazon now. I'm thinking about getting one for a future pin.

Ordered mine last night for my Getaway...can't wait!

I agree the stock bottom speaker is more of a mid range class then a true sub. Like markmon pointed out unless you are redoing the setup just leave it plugged in. Easier and likely will provide better sound.

From what I have heard from those that have done this (I soon will) it is safe since it is self powered.

Hooked mine up to HSII tonight. Sounds great! Very nice quality sub at a great price!