subwoofer to digital music and movies

Turn both the Marantz and the Earthquake volumes all the way down and powered off. Use an appropriate length RCA cable and connect the SW1 output on the Marantz 7005 rear panel to the top RCA line input of the Supernova. 

Connect the the power cable to the subwoofers AC input and the other end to you wall receptacle. Turn on the Marantz and play some music with a prominent Bass Drum content at a normal listening volume.

Set the Auto switch on the Supernova to on and the X-over Freq. knob to a 10:00 o’clock position then switch on th power. With the music playing slowly turn up the subs Volume to a level that seems appropriate. Set the Phase switch so the sound of the attack of the Bass drum sounds it’s tightest.

Refer to the Marantz manual room correction adjustment to further adjust the subwoofers crossover point and output level. 

Optimal subwoofer placement can can be achieved by looking up subwoofer crawl test. 

Thank you for the response. I appreciate it. 
Couple of point - first I've read when connecting .LFE from Marantz you are technical using the Marantz processor to adjust the X-over frequency and at that point the subwoofer internals are turned off. 
Secondly - the questions remains how do I best connect both the high level line (speaker connection) on the sub for my 2 channel listening and also the .LFE from Marantz for HT. Is that even possible with this sub? Or will I need to purchase a REL? 

First point: Depending on the functionality of your Marantz it most likely sums the LFE signal sent to the Earthquake. Even so, the lest demand you put on room its  correction the better. Getting the subwoofers crossover and gain as close as you can before running room correction will lesson the equalization applied by the Marantz as well as give yourself a baseline of where you like the subs performance against that of the room correction software. The same goes for your speakers. The more evenly spaced and distanced from the listening position the less correction is needed. 

Second point: I believe the Marantz has a single subwoofer or summed LFE output SW1 which usually cuts off at 80Hz. The SW1 output is most likely  summed. I purchased an RCA Y-block to connect both of the subs inputs and heard no difference.

This manual may not match your sub but you should get a general idea of connectivity. Good luck with it and have fun in the deep end.

http://earthquakeeurope.com/Products/Home-Audio/Subwoofers/MKVI-12PIANO/Pdf/EU/MKVI-12PIANO_manual_E...