love the setup but hopefully you didn't pay too much for that ESW-C10! That is an entry-level subwoofer and is insanely outclassed by the HSU 15" sub. I'm shocked it hasn't blown up trying to keep up with the HSU. How on earth did you integrate the C10 with that monster HSU? It is clearly the "weak link' in your system right now.
if utilized lightly, e.g. just as a nearfield supplement to smooth out a null in the 15H's response and even out the bass in the listening area, I could see it working... but otherwise I might think about returning/selling the C10 and saving up for a second sub that is a real match to the quality of your other speakers.
anyway, glad you are enjoying the new rig! don't mind my nit picking