What is you preamp right now?? I will suggest you a good route, and in general the easiest, and what I found the best sound with never distortion or added color at loud levels that I could ever hear...You could sell your current pre, Buy a mcintosh preamp with 5 band eq built right into it, #1 if you pick up something used you will never lose money on it if you decide to move on down the road cause its mcintosh, #2 you get to keep the hi end status without adding a cheap plastic eq into the system, plus the mcintosh pre's are some of the best sounding out there, and will go low...
The models with the 5 bands have a 30 hz band so unless you are looking for 20 hz this is the best for simplicity. So if you can sell your current pre go for this, Another plus to a mcintosh is it will come with a variable loudness control, really contours super nice to listening levels and always makes your speakers sound filled out and full not just a loudness button, but some might only have the button.
Also they sound warm and smooth. Other options for anything good will require you to buy a pro audio unit, and unless your system uses balanced XLR you will be doing some adaptors to connect your RCA's. Watch out if you choose to go looking for a cheaper Consumer audio product, some of them only go as low as 60 hz or 40 hz... but 30 hz is plenty for anything on a music recording.
I am not speaking any home theater here with subs anyway but we don't know what your equipment is either. Just a suggestion, I myself sold my mcintosh because I ended up with a active crossover speaker system and have no use for an eq being I have a limitless parametric EQ built in connected to the woofers only, but still highly recommend mcintosh pre's for the sweetest bass pounding simplified 2 channel systems.
