Subwoofer connectivity question


I've got a lightspeed attenuator, a prima luna prologue 5 and a Parasound Z Dac.

What is the best way for me to hook up a sub? I was thinking if I could find a sub with RCA inputs and outputs, I could put the sub in line between the lightspeed and my amp. If the sub filters the signal so that its sending a high pass signal via RCA's, if I put in line before the amp, it would only be amplifying 80-100 hz and higher thus relieving some of the load of my amp in the process.

Anyways, what are your ideas on the best way to hook up a sub to this particular set-up (DAC, Lightspeed, Amp...)?

Thanks for your time and input!
128x128b_limo
I use a pair of Gallo TR1D subs, and run my bi-wired main speakers full range. The subs are connected speaker level with a short piece of speaker cable from the low frequency terminals of the speakers to the subwoofer inputs.

The subs are positioned next to the main speakers so this arrangement is tidy. The crossover and level controls are utilized on the subwoofer for a perfect blend.
The REL "high level" input system is brilliant as it stays out of the way of existing hookups, the amp likely doesn't know it's there (puts a very high impedance load on the amp) and lets your mains remain unmolested...I spade my REL at the amp and banana the main speakers so everything fits neatly, and the REL blends beautifully and sounds great.
Hi B Limo, your dac is fine with a low output impedance your Prima Luna is fine with a nice high input impedance.
To see if the sub will match ok I need to know what it is and if you have a link to the specs.

Cheers George