helomech,
I bought a pair of C7’s used , they were well broken in. I had the same problem with them lacking bass. I had them set up for nearfield listening. What size room are they in? I think that if the room is not that large you would be better off with the P3ESR or a Spendor 3/5R2 ( I own both ) would be a much better choice! You did say you like the Epos better than the 7’s!
I bought a pair of C7’s used , they were well broken in. I had the same problem with them lacking bass. I had them set up for nearfield listening. What size room are they in? I think that if the room is not that large you would be better off with the P3ESR or a Spendor 3/5R2 ( I own both ) would be a much better choice! You did say you like the Epos better than the 7’s!