I like a few different ones, depends on the duty. For bottom to top, Hypex modules, work real well. Mine are from Nord, in the UK, and got wonderful service. There is an option for volume control, rack mount, buffer board, opAmp options. There is a company called VTV on eBay, they have Hypex modules also, state side.
Your running a 2496, Behringer? That will give you 6 lines out with any signal you want for subs or otherwise.
I use them for all my, bass management including servo bass, MB / Bass columns, and standard low rider bass bins (under 36" tall). I use Behringer 12Ks for all my bass work. 450-550 for 4.5K per channel, and bullet proof. They are good to 2 ohm or less. I think I paid 1400.00 for 3 new amps wit h3 year warr.
Full DSP, on the fly correction, for 6 channels. 2496/12k x 3. I’m a Mac guy so I have tone control to boot.
I mod them and disconnect 2 of the three fans, and put one on a toggle switch. They work perfect and have volume control, LP/HP filter, mono/stereo output. Did I mention 4.5K at 2 ohms and 3K plus at 4 ohms. LOL NO NOISE! Dead quiet, on the floor noise.
Second, my little toggle switch addition, makes for late night, low volume listening, with a flip of a switch, no fan noise, I’ve seldom gotten them warm without the fan, much less with, and with THREE, you’d be DEAF, if they ever got warm, they can really pump it out...VERY low distortion.
Regards