Your sub experience: Easy or hard?

Not likely I can add much other than a brand that hasn't yet been mentioned: the NHT SubOne. Besides sounding clean and tight, it has a very useful "controller" that sits on top (or can be placed in your rack) that controls volume and has a switch for "Flat" and "Video Contour" (the latter for movies, obviously). It's in my main two-channel music system, so it's set on "Flat." Most importantly, it has lots of ways of connecting, including both high pass and low pass filters, and, of course, a phase switch. I use the high pass option, sending everything above 50 Hz to the mains. I've found that locating it to the side of the mains, and facing ("firing") across the sound field, helps a lot with integration. The result is a perfectly natural bass that goes considerably lower than the mains alone without ever sounding boomy. Rock has real punch while acoustic cellos and basses just sound vital and real, not exaggerated.

My only sub in the main system is a dual side-firing Tannoy, effectively two subs in one box. Tower speaker mfr says DO NOT high-pass; allow the mains to run full range. These are rated to 22Hz but have a peak at 35 and roll off pretty steeply below 31. So I set the sub crossover at 31Hz, rolling off at -12dB/octave above that. Basically you're only conscious of the sub with tones in Octave 0. Above that the contribution is so subtle you would notice it only by its absence.

Now, as to placement, I can move sub around using a carpet scrap on a slick wood floor. The dual side firing design seems to integrate best when placed between and a bit behind the mains. Maybe some day I will have time for more experimentation with settings and placement using good test recordings. Room configuration rules out the sub array, so need to simply fine-tune what I've got. Overall, though? Definitely worth the effort as deep bass is very important to me.

Two Hsu subwoofers - using one to handle 90hz and below with Quad ESL63s and a smaller one in my recording studio/office with JBL 4401 monitors (old school).  Very easy integration. Both sound great. Transition between the mains and subs can’t be heard. And taking the low end load off the ESLs opened them up even more and lets me push them a little harder, when needed. 

If was difficult at first. I tried to follow the manufacturer’s suggestion in the beginning which was a good starting point, but once I started listening to what pleased me sonically that’s when the magic happened for me. Everything became enhanced highs, mids, and of course bass. 
 

Good question, Erik. 
 

Best regards,

East

I'm running two JL Audio F110s with auto room optimization, which is the main reason I say sub setup is very easy. The JLs are active and non-ported so they work pretty much anywhere I put them. The ARO adjusts for room modes. I also run a JL Audio CR1 active crossover to set the LPF & HPF, which I think is also a reason why my subs are so easy to integrate. My speakers are Magico Mini MkII, which sound great on their own but the subs add a lot of dimensionality and grip. 10/10 would recommend.