I did a quick comparison test between the Onix X CS, and my old Polk CSi3 center. Of course the Polk was as bright and harsh as always in the high freq range, but it had considerable more clean, punchy bass than the Onix.
In fact, the Onix sounded muddy, or muddled. Now it's not an entirely fair comparison, since the Polk has 3 ports, so I assume this helps get more perceived dB in the low end, but it shouldn't give it an advantage with bass clarity. The Onix had no "punch" by comparison.
I was wondering if the X-CS Encore crossover would help with this?
I was just using a Harmon Kardon receiver in my garage for the comparison, switching back and forth between speakers. No other speakers were connected. Perhaps the Onix needs a better amp to drive it? It did require a bit more volume to reach the same levels.