subwoofer to digital music and movies

I am a bit confused on how to best play music and watch movies with my new subwoofer. My recent purchase was an Earthquake Supernova MIV 15 inch sub. My 2 channel music listening is all digital via Benchmark DAC1 used as a preamp and for home theater using my Marantz AV7005 preamp. Question is: how do I best connect the subwoofer such that it is part of the 2 channel listening experience (Benchmark) and playing movies using my Marantz preamp? 

Simaudio w5 (2 channel amp)
Earthquake Cinova Grande (5 channel amp)
Von Schweikerts VR4 + center + surrounds 
Benchmark DAC1 
Earthquake Supernova MIV 15
Marantz AV7005
OPPO 105
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.
Thanks for the reply and it makes sense. The sub I have does not have the DSP and is one level lower supernova MKIV - which happens to have the high level input along with the LFE and hence my question on using both. 
Instead should I selling my Earthquake sub for a REL or other brand? 
What is the Earthquake not offering you or what is your goal? 

Why REL?
Earthquake is great. The form factor is big and not pleasing to the eyes in the Family TV room. What I’ve heard of the REL’s is that they are for both music and HT and can be connected to both at the same time. Not sure if Earthquake can. 
REL is garbage for home theater and any music with real deep bass. Only good >35Hz.

Rythmik, HSU, JTR, PowerSoundAudio, and SVS. These are the only major brands selling >$500 subs that have a good bang for buck.

@ghulamr Go for the REL. Have a look at their official website and see if you can match your speakers to a recommendation on their site. Yes, they do have .LFE and stereo pair on separate connections. HT for Home Theatre subs, or up unto the S Serie if you have the dough. The HT/7i is a great model for HT first and also stereo. They have good woofer size to "move the air". I was a MK person but decided on RELs for music. :)

There are a number of subwoofers that offer dual system connectivity. You may need to do some homework and ask questions via email. Keep in mind a subwoofer purchase should last you through many system changes. 

After reading Stereophile's Larry Greenhill review of the $800 MartinLogan Dynamo 800X were he needed to use a $3500 crossover to reign in the effects of the designs built in nature. I'm reminded of a similar experience with a friends $8000 British made REL Studio III.

Aside from moving production offshore REL hasn't done much in the way equalization R&D. Continuing to take the signal from one's amplifier as a means of extension or whatever they call it didn't begin to cut it when we stacked it up against a couple of modern designs. I guess I stand next to mzkmxcv in my regard for the brand.

There are subwoofers that can easily integrate unnoticeably with any speaker whether its playing music or a movie. A subwoofer / speaker matching list? WTF! 

@m-db Please don’t denigrate other peoples opinions. You may have your own opinions, but unless you are faulting the REL website and their attempt to match speakers and subwoofers from their range, please don’t be rude to me.

REL have been making only subwoofers for 2 decades according to their website. Other brands have added to their list of equipment with speakers and so on.

I can only offer my opinion as read from the REL website, my Hi Fi dealer, and my own experience with various manufacturers subwoofer speakers. I prefer MK for subs, but I have good experience with my current REL S/3 pair.

If you think there are better subwoofers, please state what they are and your experience with them.