Do high level sub inputs really sound better?

I have two subwoofers, one in the living room for an LP-sourced stereo, and one in the 7.1 home theater rig.

For the home theater rig, I use the low level input and a fairly low crossover point handled by the surround pre/pro.

In the 2-channel system, however, I use high level inputs. I've tried it both ways, and it's not even close. Using low level input, the whole system sounded lifeless and uninvolving, and it seemed like I had to turn the subwoofer way up just to hear it where it should be.

I also noticed a second improvement when I upgraded the speaker cables from the power amp to the sub. I went to some of those garden-hose sized PS Audio XTreme Preludes from an Audio Advisor sale ($50 for 6' pair), and it made the entire image and clarity bloom.

I first heard of this reading Pierre Sprey's free audio tips on his Mapleshade website, http://www.mapleshaderecords.com/audioproducts/freeaudiotips.php, where he says,

For seamless subwoofer sound, use only the speaker cable input, not the RCA input. In addition, connect the two main speakers directly to the main amp output, not to the subwoofer's output. Always fire the subwoofer driver left or right, not at you or down into the floor. Set the crossover at the lowest possible frequency that doesn't leave a bass gap. You'll be amazed at the overall transparency you gain.

When I first read that, it defied all logic, but I tried it both ways, and at least for 2-channel stereo for music, with the Mirage subwoofer's I've used (LF-100 and LF-150), it definitely works better.

Pierre brings up a separate issue in his tip. Running the mains full range and using the sub as out of the way as possible keeps the bulk of your music uneffected by the sub as well as not having to go through the extra degradation of the crossover. The only down side to this is if you want to prioritize unburdening your mains with low frequencies by crossing them over higher. Crossing over the mains definitely has advantages, especially when playing loud, but the disadvantages in terms of transparancy are significant.