Hello Mr. Graser
Yes, you can connect an active subwoofer to the Connect.
Simply connect the Connect's Line Out to your Sub's Line In.
I assume you meant the inputs on the sub,
You use the line input there.
The LFE In is the bass channel of a Dolby surround system.
Only the bass tones that were sent to this channel during the mix are reproduced there.
With the Line In, as with a stereo system, all frequencies are received,
but only what you set with the crossover,
will be reproduced;)
Best regards
Beat Frei