Quote (vittujenkevat @ 17 Dec 2015 06:22)
You have connected those speakers together with speaker wire? If so, I guess you could put for example Dayton sub 1500 between the speakers and it should control the volume that way. Not all powered subs have this option tho. This mentioned sub is pretty nice for price, another great option is Dayton sub 1200.
Ahh can't edit anymore.. Putting sub between the speakers might not be ideal tho, as when there are some low freq input to only right channel you are not passing it for the sub. So it would be better to have sub first in the chain, but this way you cant use the volume control of your active monitors. Those monitors have really poor connectivity I have to say, if I was buying active monitors I would of stayed away from those for that reason. To get good 2.1 setup you are pretty much out of luck with those speakers if you want to use sub and the volume control of monitors. With separate volume control it is possible, ie. using avr or amp.