I think my solution to soft concrete would be to epoxy some metal plates to the concrete - but I guess that’s not an option in a rented apartment. Although the landlord probably wouldn’t ever find them… 
I sometimes wonder if the major contributor to ‘differences’ in sound with floating plinths / ikea chopping boards (they get everywhere… ) is actually positional - nearer the ceiling and further from the floor.
Tweeter vs ear height indeed. I’ve wondered the same with many of the isolation devices people use.
Size of speakers has nothing whatsoever to do with how loud one plays music, - someone with small speakers may well play louder than someone with large. Oddly it is a misconception among non-hifi people (oooh, they’re big speakers, how loud do they go?) but very odd to hear the same from a fellow hifi enthusiast! Big speakers are much more to do with achieving full bass. That of course leads back to the thread topic, in that bass , with its much greater energy, more likely to cause vibration of sensitive gear if placed either too close or in corners where bass energy tends to be greatest. Best position might be the very centre of the room…
This big v little conundrum is my issue at the moment, my room is small so my natural instinct is to have stand mount speakers, but I like the thought of a fuller sound experience by going floor standing speakers.
Thankfully I am going to be borrowing a pair of stand mount and floor standing speakers to audition which will point me in the right direction.
My dealer says if you can accommodate floor standers then do so, only go for stand mounts if you can’t.
I suspect it’s a little more nuanced than that but if you want a bigger fuller sound then yes to floor standers.
Gary
I have floorstanders in my 3m x 4m cabin. I was a bit concerned that they may have been too big in the first instance but after 13yrs I wouldn’t now consider standmounts. The sound is full and immersive and is a pleasure to listen to at any volume level.
That is something I’ve never understood, given that the space effectively occupied by standmount + stand can be much the same as a floorstander! A larger box enables better bass, though the greater design challenge of doing bass well means that for the same sound quality in other respects a bigger speaker with deeper/fuller bass costs more, and often not just proportionate to box size.
When you say your room is small, what are the dimensions?
Would it have helped if I’d added a couple of emoji?
Go for standmounts if you have cats……
Probably! Sometimes hard to know when someone is serious and when not!
My small listening room is a spare bedroom measuring 9ft x 8ft, plasterboard walls if that helps.
Yes indeed small (I asked because different people have different ideas as to what constitutes small - the last person saying they had a small room turned out to be 16x12’8! If your room’s height is 8ft or 9ft making two dimensions the same makes more tricky…
I think the idea of too much speaker for the size of room has been debunked many times by engineers. While a speaker can be too small to fill a room, a speaker can’t be too large in any sense other than visually obtrusive or inconvenient. You can certainly turn the volume up too much for a room.
Quite a few pro audio designers have indicated that “too much speaker for a room” is utter rubbish. If a speaker doesn’t interact well with a room (which is definitely a real issue) the size of the cabinet is not the issue so much as the other aspects of it’s performance which can equally be a problem for a small speaker.
Given a reasonably even(ish) frequency response, the low frequency energy should be proportional to the other frequencies at normal listening levels. Hence why you can have too small but not too big. This all contradicts years of posts from myself as I had long held the firm belief that speakers could be too big and over energize a room.
Right now, for the first time in my life, I’m suffering from slightly too small a speaker for the room.
As for the TV issue, I think we all understand this is often an unavoidable compromise. I have a curatain rail mounted 30cm from the front wall and runs the width of the room with the TV, AV speakers etc wall mounted. Once my curtains arrive, I can just close them and the AV stuff vanishes and it’s just two speakers backed by wall to wall, ceiling to floor fabric.
I like the sound of this.
Where can I buy one?
The main issue I see for small rooms is the need or otherwise for a loudspeaker to be away from a wall. I could imagine the old Naim designs working well in small rooms as they sit right up against a wall. If you pull any speaker away from a wall in a 9x8 room then it’s going to be snug in terms of listening distance. Finding a good speaker that doesn’t mind being right up against a wall would be my choice in a small room. DBLs? I joke, but don’t I recall that one of the Naim engineers had DBLs in a pretty small room?
The Neat Ministra is supposedly ok for closer to wall mounting, ProAc Tablette, and I think the PMCs also work close to walls?
Or just get rid of the cats.
Neat Motive and Elite floor standers are definitely on the short list as are Kudos Super 10 and 20’s, both companies speakers can apparently be located close to rear walls around 20cm my ATC’s are further out at 28cm.
Obviously a home demo is a must and one that I will be insisting on prior to purchase.
I guess ATC know a thing or two about speakers and their interaction with rooms. Addressing the question of choosing suitable speakers for rooms of different sizes, they say there are no hard and fast rules, but, in general, smaller speakers are better suited to smaller spaces, whereas larger ones are better suited to larger rooms. That’s my paraphrase and it’s worth looking at the original FAQs on their website.
Roger
Simple solutions are always best 
Dipole speakers with thin light membranes like electrostatics or ribbons. Dipoles only pushes sound front/back Nothing to the sides or upwards. Light membranes generate less vibrations - especially without a big wooden box.