It is not looking like much of a competition. That Elac is a true sub with an excellent driver, which will dig down to 18 hz, as stated, no problem. One of the supposed competitors with a -6db down at 27hz is a ’woofer’, not exactly a ’subwoofer’.
Besides...if you have a purist rig, no measurement tools, etc, that elac came with some unique tools in its app. You put that elac in a location. Run the 2 cal sweeps with its app, one right next to the driver and one at your listening position. It will show you exactly what it measured and how it corrected for your listening position.
If it shows a huge suckout, null, etc on the app’s measurement, move the sub around and run the sweeps again, i.e., it gave you a integration tool that’s user friendly even for guys who may know not know anything about subs or room acoustics. Your chances of success could be much higher. Subs won’t magically integrate without availability and usage of the right tools...despite what the marketing said.
Ideally, you should lop your 2-way bookshelf speakers off on the low end around 100 hz or so with ’bass management’ (probably even up to 120hz with dual subs, depending on the room and not localize anything), i.e. prevent that speaker’s woofers from moving too much and pass anything below to the sub. If it moved too much, it will screw everything up at the upper octaves. In your case, it is tasked to handle everything upto 2000hz before some tweeter took over, i.e., it has a lot on its plate. So, you should be a good samaritan and lend it a helping hand. If you can eventually get your hands on something like a Yamaha R-N2000A, R-N1000A, R-N800A, etc amp with such features, it should do the job.
