Speaker Level and LFE Sub?


I need a sub that can combine the high level signal from the output of my 2 channel amp with the LFE of my surround preamplifier. I have a REL B3 right now which can accomplish this task. However, I am not totally happy with REL. I have an NAD M2 amp and the REL doesn't do great with the high level connection. I tried using the REL cable made for digital amps with no significantly different results. The NAD M2 doesn't have a line out for sub. :(

The G928, REL and Thiel's SS1, SS2 etc with the smartsub integrator are the only 3 sub manufacturers I can find that can run speaker level and lfe contemporaneously. Any other subs that can do this? Any external sub eq or dsp that can run both inputs at the same time?
128x128dallasjustice
I read the manual. I can see that the super cube take speaker level inputs, but nothing in the manual says that the sub can safely take both LFE and high level at the same time. Are you doing this with a supercube? I just wouldn't try it unless the manufacturer has tested it to make sure grounding problems aren't going to destroyed my amp. BTW, most subs that take high level connections cannot do both high level and low level at the same time. REL is one of the few exceptions.
Sorry. Maybe i jumped the gun. I read this on their website:
"Both speaker level and low-level inputs are provided as well as a separate direct-in LFE low-level input (which bypasses the crossover network) which may be used by itself or in combination with left and right channel high- or low-level inputs for the ultimate in subwoofer flexibility and performance."

I called velodyne regarding their DD series subs a few days ago. Rob said that their subs do take speaker level but not at same time as LFE. The SRS looks like the same eq as in their dd subs and I can't find anything in the manual that says it can do this. Maybe I just need 2 subs.
Can I ask why? Is the NAD in a separate 2 channel system or are you using it as the front L/R amp in a combined system? If the former, you do not need simultaneous use of line and speaker level inputs. If the latter, the LFE/sub output of the processor will handle it all at line level.

Kal