Hey, so im using an Apollo Twin x interface, and I had some questions regarding volumes of the outputs. So im trying to set up a subpac(tactile subwoofer), as well as the monitors. So my monitors are obviously in the monitor outs, and the subpac plugs into the headphone out. Now im trying to calibrate my speakers and volumes, but im not sure if this will be correct. So lets say I turn the volume up on the monitors to 12 o clock on the interface. Now I need my subpac (headphone out) to be the same volume as the monitors. If I put the headphone out volume knob to 12 o clock as well, are they essentially going to be the same volume, as if it was getting the same signal? I assume the output on the headphones wouldn't be as high so I might need more juice to kind of volume match them. I know depending on the gear, and speakers, they may have different input sensitivities, but besides that would they essentially be getting the same volume? Not sure if that makes sense, but basically I just want my subpac getting the same signal/gain as my monitors, so the sub is in sync with the rest of the music. Thanks!