I think in the past Steve has recommended just going speaker wire to the sub-woofer assuming it has those kind of inputs.

If the subwoofer has a high-pass filter and you want to filter out the LFO to keep from pounding those traps, then you'd have to go through the subwoofer first, probably through the RCA inputs.

Both are good brands with great gear, but I think the SVS is typically a better value. Looking at a picture of the sub, the speaker line in is probably best.

Keep in mind, if it does have a crossover on the line-level input that can filter out the low frequency and pass everything else, that would make your SE84 more efficient as it wouldn't have to work as hard reproducing those low frequencies. If you use the speaker line input, you're simply adding bass to what's already there with the traps.

The advantage of that high level speaker input is long runs would be less damaging to the sound compared to running through really long interconnects.

*if* your sub did a high-pass filter on the RCA outputs so your amp wouldn't have to work so hard - you would go RCA out of the source, *through* the sub, so the Zen.

If your sub doesn't have that kind of cross-over on the RCA, then simply run speaker level and don't worry about it. Focus on finding the best placement and blending it in with your mains.