On some eq's it says sub output or sub channel. from the ones i've seen there is only one. What does this mean and how do i hook up tri subs to the eq.. thnx much
well, subs are pretty much always mono, even using a stereo amp. stereo separation ends around 250Hz, which is the bottom end of the vocal range. Below that, there's no need to separate L and R channels, as you feel it more than hear it, so you want the subs working together to move the same air at the same time.
Anyway, the sub level on an EQ is so you have a dedicated channel to handle sub output, and the ability to control the output volume of the sub to balance it to the rest of the system.. or to turn the sub off completely as desired. you can just split that RCA signal to both channels of an amp if need be.. use Y splitters, and if neccessary, a line driver to boost the signal if you need to go to multiple amplifiers with a single line output.