jm labs profile 918's vs 928's

i recently purchased jm labs profile 918's. although i'm pleased, seems they're a little lacking in the bass dept. i was curious if anyone owns a pair of 928's, and what they're opinion is? thanks.
I got the 918's and a Rel Britannia B3 subwoofer. It blends perfectly. Top to bottom pure musical excitement. The 928's dont play much lower. Just louder. Get a JM Lab Profile sub if you want to match the wood on your speakers. The sub picks up where the 918's leave off.