Connecting two powered mixers

The Bose B1 bass module is designed to handle up to 125 watts into 8 ohms 40-200 Hz.
The Yamaha EMX 5000 is full 500 watts, and full range. This is not a particularly good match.
EMX5000 Powered Mixers Mixers Live Sound Products Yamaha United States B1 Bass Module Bose L1 Encyclopedia FAQ Wiki

First it is certain that you would not want to plug both outputs of the stereo power amp into one speaker combining both channels into the same speaker. (see image from manual below - also link to manual)

Next I would be very concerned about only using the one side of the main amp out as it could cause an unbalanced load, or you could be driving the load into dead air connection and any of these conditions are destined to cause premature failure of the power amp.

Taking a quick scan of the manual for this unit, it appears what is pretty common to most powered mixers, hook up two matched speakers/loads to each chanel of the output.

Your best bet is to shed those monster cabs, there really is no need for them especially with this sized powered mixer, and get yourself a nice pair of full range cabs like EV1202;s, EV SX300's, or some nice 2 or 3 way 15" JBL's/

Just my opinon.

Link to Yamaha EMX 312 Owner's Manual:

Yamaha EMX Series Owners Manual

More information needed such as what was it doing when it quit, was it loud ..etc.

Yes. You can use powered speakers with this board

Did sound for a southern gospel group, using a yorkville powered mixer. Not familiar with your mixer, but, on the Yorkville I had an unused 1/4" line level output with the monitor mix on it. I bought a cigar-sized, 3-channel headphone amplifier / splitter from Radio Shack, called a Boosteroo. Has 1/8" stereo plug that I adapted to the mono output, with a 1/8" stereo to 1/4" mono adaptor. It receives the line level (monitor in our case) signal and supports up to qty 3 - 1/8" plug headphones. Battery operated. No volume control, so I added an inline dial (rheostat) volume control cable. Can't pull up on Radio Shack, now, but, found it available, elsewhere, online. Worked great for me!
Good Luck SdDude

There is no way to hook up any form of lights to the Yamaha EMX512S. If you want to use DMX lights, you would need to buy a DMX controller. There are both analog and software controllers. Controller prices can range from $50 to over $500.

The IPOD does not put out the line level and worse, the IPOD is stereo so you need a mixer to mix the L and R channels before sending them to the line level input of the DSR112. Shorting the L and R from the IPOD together as can be done with commonly available adapters gives poor results. The input of the speaker is a balanced input and needs to be XLR or TRS BALANCED input. A 1/8 inch stereo jack to 1/4 inch adapter results in the two channels of the IPOD subtracting and very low signal that is corrupt. Do the job right and use a small mixer to combine the L and R of the IPOD.

you can just piggyback the mixers - take the outputs from the mackie mixer (assuming it is NOT a powered mixer) ... those should be line level outputs - send them into a line level input on the digi 002 and then set that channel on the digi 002 and once set, just leave it, and control the mackie channels individually ... should work fine ...

For audio expertise and PA system help with feedback and noise, try our new DVD "PA Systems for Small Groups" at www.rexark.com

There was never anything mentioned about the 18 yamaha sub in the hook up process

Your powered mixer does but the model number doesn't match any Yamaha models. Double-check and look for the manual at Yamaha's website. It probably the 300 or the 512.

http://www.yamaha.co.jp/manual/english/search.php?div=pa