OT: PA Rig Setup Question

cool, so i've got two 12'' powered mains that i'm diggin, but i definitely need a subwoofer to add that needed low end (rule 1 of spinning dubstep: there isn't enough bass until you don't feel your earwax coming loose). found a nice infinity powered 12'' sub (usually used for home theaters i think, but all the reviews point out that it's very clear sounding). so the only confusion is that the only inputs on this thing are line-level/pre-ampd rcas. the speakers i have are powered, can i run the output of one of the speakers (each of the mains has an output that echos the input 1:1) to this sub? or would the signals be incompatible? thanks guys.

Back in the day, I used to use a PA where the subs had speakon ins and outs. Amp would go to the sub in, and then from the sub out into the main speakers. So 'daisychaining' speakers is not unusual.

If the outputs from you speakers are line level, then it should be fine for running the sub. Run any tests you do at low volume and always switch the sub on first, switch off last. The potential issue is of stereo imaging - if you're only connected to one speaker, and the bass isn't centred, it will affect the volume of bass from the sub, possibly from track to track. I would assume bass is often 'centred' so this shouldn't be a problem.

Alternatively, run the sub from a separate 'out' from your mixer if you have one. This allows you to tweak the sub volume from the mixer too. Or get an audio splitter to split the master out into two - one for your main speakers and one to your sub.