Do you listen nearfield or do you have a standard configuration?
In any case, I’ll share my experiences, as some of it might be helpful (although I don’t have any experience with the W5s)…
My room is a similar size. I have both a main system, and also a desktop system, in that room.
The desktop system has small, full-range Audience ‘The One’ loudspeakers, so has limited low-frequency extension. I first added a REL T-Zero, but it was too small, at least in my space. It sounded overstrained and would not integrate in a satisfactory manner. I changed it to a REL T-5, which was a notable improvement. But then I added a second T-5, and it really came on song. So with dual, left-channel/right-channel T-5s, each subwoofer expends less effort (esp. helpful with smaller subwoofers), they integrated seamlessly and expanded the soundstage.
However, for my main system, with Dynaudio F260s, I use dual vintage REL Storm IIIs. They integrate effortlessly with the bigger loudspeakers, and provide much deeper, room-filling extension. For my own preferences, using the small RELs here would not be satisfactory, even though they are totally suitable with my desktop system.
It’s only part of the story, but it’s interesting to compare the frequency response…
- T5: In-room at -6dB: 23Hz
- Storm III: In-room at -6dB: 16Hz
I also have a bedroom audio system with Audience The Ones. I had ended up with a spare Storm III, so figured what the heck, I’ll try it in this system. I didn’t really expect that the big REL would integrate properly with the little ‘The Ones’, but was surprised that it actually worked superbly once I got the positioning and settings of Storm III correct. It may help that the REL is much closer to the listening position than the ‘Ones’, thereby counteracting the group delay of the big, ported REL. So the Storm III has remained there ever since.