ANY sub (self-powered), using line in/internal crossover/line (minus low bass) back to preamp is the best way
I thought this also....But just this week, I decided to try this hookup with my system
Schiit Freya preamp / VTA ST120 Dynaco Tube / Node2i / Gustard X16 DAC / KEF LS50 Meta / SVS 1000 sub....
Feeding the signal through the sub and back to the power amp totally destroyed the sound imaging and stage of my system.
On one particular track, Rolling Stone "Symphony For The Devil".....When the power amp is directly into the LS50 speakers, the piano is way right of the right speaker. It so freaky that you would swear there is another speaker to the right of you.
When the signal is routed through the subwoofer, the piano moves TO THE LEFT of the left speaker and seems to be coming from behind the stage!
I tried it back and forth many times. Checked and rechecked my wiring. Used the PHASE control on the subwoofer in every conceivable position (Its variable on this subwoofer)...And the results are always the same. I had three other people listen to it to be sure it wasn't MY ears playing tricks on me.
I'm totally convinced that taking a great audio signal, and routing it through yet another piece of equipment and then back into the power amp and to the speakers is a bad idea.
I have RCA 80Hz High Pass filters that I can insert before the power amp feeding the LS50s......This does not do anything to imaging or sound stage....but with LS50 it muddies up the upper bass. The LS50, IMO, want to be played full range with a subwoofer and let the natural 50Hz roll off play into the sub with the sub crossed over at 70Hz.....Not so with my Magnapan MMGs....They love the bass totally removed under 80-Hz......Different speakers want different subwoofer set ups.
