I know from personal experience that the Rogue 99 is extremely sensitive to what is supporting it. Putting it on BDR #4 cones really tightened the bass for me and helped the PRAT substantially. If you haven't already done so, I recomment trying this tweak first... I used the 99 in a system with the InnerSound Eros and ESL amp; the bass was total mush until I installed the BDR cones.
Also, if you're using an early version of the ESL amp, it had some problems with bass control. The problems had to do with the feedback configuration (or lack of it) and was fixed in the version 2. I believe that early versions can be updated by InnerSound.
Also, if you're using an early version of the ESL amp, it had some problems with bass control. The problems had to do with the feedback configuration (or lack of it) and was fixed in the version 2. I believe that early versions can be updated by InnerSound.