willemj869 posts02-24-2018 2:09pmREL pioneered the speaker level connection for better integration, but these days many other manufacturers have followed them.Lets be clear and for quite some time. Many other manufactures provide high level connectivity to accommodate systems that lack a second set of low level RCA outputs for typical subwoofer connection. Some use the high level connection in conjunction with high pass filtering to filter the main speakers low frequencies. Non that I've experienced suggest this high level connectivity as a preferred method nor have I ever experienced high level connectivity used in professional audio applications.
Information suggests REL developed their own transformer design to aid in their proprietary high level connectivity. Regardless, every REL subwoofer I've connected to my system using their high level connectivity diminished my sound stage and added a level of noise. And in all cases their integration and performance was greatly improved by Velodyne Room Optimization and, I'm told, by other DSP methods.
The results of direct comparison are often ruthlessly revealing. In the end those results are a matter of subjective personal taste.
Robert OP, a DSP equipped subwoofer will last you many years and more importantly will easily adapt to most any room and or speaker you choose during your audio adventures. Tighter, less sloppy, slow, musical or home theater, are all red flag adjectives that describe subwoofers simply out of control. Add some DSP and many of those same units could sound quite good.