Revel B15 Second Sub Question

Well I just bought a Revel home theater speaker system.
4 M20s
2 B15s
1 C30
I have not received them. They are on there way. The subs will arrive first on Tuesday.

I was looking at the back of my Krell HTS and I don’t see a second connector for a sub. What is the best way to run a second sub? Also can I stack the subs on top of each other? Do I need to put something between them?
I have never heard Revel speakers. Hope they sound good. This setup will only be used for HT.
The Revel B-15 has an output as well as inputs so you can daisy chain the subs.You would go from processor to one sub and then out of that sub to the other sub.
Highly recommend against stacking (you'll see it in the manual). Subs are too heavy and are not designed to do so. Experiment with different locations for each, then have fun setting up the eq!
My manual recommends stacking as one option on page 11 down at the bottom of the page. I wonder if there are more than one version of the B15 manual. Of course my manual does not explain how to stack the units. I don't have enough room in my corner for 2 B15s side by side. I need to stack them. Do you take the feet off of one to stack? Has anybody stacked 2 B15s in the corner?
I have stacked the B15 and all is well. They are both in one corner with a wall which would catch the top one should it decide to fall. I started listening with one B15 and it is very good but two are so much better. I programmed the bottom one to extend the really low bass 20 and below. The top B15 extends at a higher range. They work together very well. The canons from Master and Commander put you back in your seat.
If anybody is interested in stacking Revel B15s. I still have this setup with stacked B15s. I have not changed or moved any of the audio equipment. I have had no problems with speakers moving. You can not put DVDs or stuff on top because it will vibrate off, but the top speaker does not seem to move.