I prefer connection to the high level from my amp outputs. Rel's logic seems sound for recommending this as the best implementation.
REL subwofer High Level vs Low Level connection
My preamp has two sets of outputs giving me the option of running interconnect to the sub's low level inputs or running the Neutrik-cable from the speaker connectors to the high level inputs. I would think that these are very different solutions electronically and with potentially very different sonic results. Thoughts anyone?