Myrison,
The graphs are telling me that the EP600 is performing far better than the earthquake. The blue/green line is VERRRY pretty and quite flat (looks be be about +/- 4 db to me from 20-280Hz). This is with no additional room equalization as well. Looking at that 20db difference at 20Hz between the two subs is amazing to me.
The "punch" may just be that your ears are used to a non-flat curve, and your listening preference is now skewed to a specific peak frequency.
In the end, you have to keep what you are happy with. If a cheaper sub that doesn't play "true" gives you more listening pleasure, then you may just have to downgrade.
LFR1100 Actives,QS10HPx2,QS8x2,EP800,M3x4,M3x2 (Wood),M5HPx2 (Wood),AxiomAir,ADA1500-8,ADA1500-7
| 
