Thx guys for the replys! Sure there are some benefits for living in 1st floor, no downstair neighbours as the bass would go easier to downstair i guess. Behind my speakers/tv/sub there is neighbour but maybe just bedroom. And this house is build in 2011, not so bad. I forgot to mention there is also opening at the back of the mainroom to narrow "hall" which leads out of my apartment. So 20sqm isn`t whole story. Unfortunately there isn`t door to this hall and no communicating door near the outdoor, just one heavy outdoor. So sound is leaking to stairway more easily. I don`t understand why they build like this. Money saving every place, clowns!
I have HK`s avr, but it has crappy room correction, doesn`t eq the sub and it gives wrong info. Useless crap, they always disable it in reviews! New avr costs alot money, audussey xt32 would be the choice. It would be easy to buy Antimode 8033 Cinema tho. It has lift +25, but this sub won`t go that low.

Audussey would be the easy route, just get it thru and forget it. Other apps and DSP? sounds difficult.
I have tried different places with the sub. I don`t have enough long cable to move my sub to my listening position to do the crawl the way it`s supposed to do. Sub is now in between my right and center speaker. I have tried move it to left same place or little more (then the tv stand isn`t back of the sub). I just can`t hear a difference.

There is possible to put the sub behind both floor speakers near the back wall, but i have heard that is not optimal. Also there is corner place, but that is the worst i have heard. I have used different music (suggested for crawl) to test it, but sounds same.
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It is very hard to find reviews different subs played with moderate volumes. I don`t really care the crazy numbers, cause i can`t use the sub that way if i don`t want to chat with cops. There is some talk that with reflex box if u bring it high levels db, u can really feel it in your chest etc. So if i buy 12" ported sub and it behaves the same like 12" closed one. Not good deal for me. And usually they are bigger and harder to place optimal.
So the real question still is this: Movie playing at -35 volume level from AVR:
12" XXLS400 Closed box
12" Monolith reflex box
Do they sound the same at that level? I am afraid that Mono wakes up alive when you crank the volume more, so no benefit listening it "low". Am i wrong?
Thanks!
Edit. I have concrete walls and laminate floor, the left side is window all the way almost. I usually hide them with thick curtain, also thick rug and futon bed, little tv chair. Gemini2 is on spikes. From the back of the sub there is 67cm to back wall. My listening place isn`t near (back)wall.