Interesting article. I kept reading until they started about vibrations in the enclosure of the sub. Sonos unique design doesn’t do that. 
My opinion in this is that you should not overthink this too much. Not that the sub placement can make a lot of difference, but you should try that out yourself. Put it on a schelf and listen what happens, then place it on the floor, in a corner, or out of a corner and listen again. 
Only you can decide where it sounds best. 
 

You can also put it on the main listening position and listen where the bass sounds best. Then put the sub in that spot and listen again. 

My last paragraph?

Yes, I know what Sonos says about no vibrations concerning the mini sub, but is that real? 
 

Anyhow I have moved the sub off the floor and to me there is a difference. I do recognise that different floor coverings bring about different sounds. Just put it out there for people’s to consider.
 

Thanks

The ground floors in our Home are solid concrete, which I think were screeded and tiled and then we have underlay/carpet. I find therefore a Sub works well on the floor and my own preference has been to put a sub in the corner of the room out in front of my listening position. I don’t like the Sub behind me nor under the couch like many may opt for.

I’m lucky with my lounge, as I have an extension on that room which gives me a corner in the centre of the room between the stereo speakers and that is the position where I have chosen to put the Sub. I’ve not ever considered raising it up off the floor, but I don’t get vibration. I’m also not one that likes the Sub output so high that it rattles the windows, or glasses in a cabinet - I prefer the Bass to be more subtle.

Usually the default setting is enough for my ears, my Wife prefers less, my children (who have now flown the nest anyway) would likely prefer more Bass.

But all that aside, the answer of where to put any Sub is …where it sounds best to your ears.

Totally agree Ken.

We have all different requirements and also agree that default setting to many might not work. People who have hearing loss is an example.

I  personally don’t like Bass dominating the sound. That’s why I personally think Sonos is on a winner with the Mini Sub, music seems balanced. In fact since I move to Sonos after ditching apple creation I am  so much happier with a System that actually works and not dealing with problem after problem.