It’s best to position any Sub on a solid floor, so as to reduce the risk of vibration of any objects or furniture.  The location is less important as the audio from the Sub is not directional.

Try it in any place you deem “aesthetically suitable” and decide which location sounds best to you. It’s your system, so set it up to best suit you

Ok Thanks a lot.

Andrea.

@Flyflot

There‘s a test that always worked well for me finding the best position for a subwoofer. 
First put the sub exactly at the hearing position that you are going to use mostly. 
Start some Music and walk arround the room, stay and listen at each position you could imagine to place your sub. The position you are most satisfied with audio (and maybe also design ) I recommend as subs home.

Ok Thanks a lot.

Andrea.

Ok Thanks.

Andrea

Subwoofers are very sensitive to location in the room. I use a slightly different technique from Schlumpf and the results will be similar. I play a thumping bass track and walk the room, close to the walls, with pack of Post-its and a magic marker. You’ll discover locations where the bass accentuates. Mark these spots with a Post-it. These are known as “peaks“. There will be a few peaks where bass is greatly accentuated. Mark these with !!. About midway between two peaks you’ll observe a “null” where bass is minimized. When you step back you’ll notice that the peaks are more or less uniformly distributed around the room. Placing the subwoofer at a peak will maximize its impact.

In my college apartment I discovered a monster peak and placed a chair on it. This was a favorite spot for male listeners because bass seemed to explode from within your body. If I moved the chair a few inches the peak was gone.

After you become familiar with locating peaks and nulls, you’ll be able to discover smaller peaks and nulls (at various frequencies) in three dimensions throughout the space.

 schlumpf’s idea works.  The problem with that idea is the sub may end up where your better half will trip over it.  If budget allows add a second sub.  Of course if you don’t have a better half then schlumpf nailed it.

OP asked about a Sub Mini - you can’t have multiple Minis in a room. 

So always remember:

Before going to marry her, absolutely ask her, if she loves you… if she always will stay with you… BUT FIRST OF ALL ask her, if she will agree to every place you put a sub.

 Good luck with that!

Thx… I already had. She’s amazing! 

 Mine too.  When we moved she let me take over the dining room.  KEF LS50 Wireless II system.

What a lucky man you are…