Beolab 5 by B&O

need advice for those speakers in a large living room .
50% HT 50% music.
Not sure exactly what advice you're seeking. If you're thinking about a purchase, I'd only note:

I heard them at B&O's Beverly Hills showroom a few years back and they sounded absolutely awful. I really wonder whether they were defective (because there was an audible rattle at volume), but the staff seemed to think they sounded great.

So, if it's purchase advice that you're after, my only suggestion is: Do not buy these without an audition. Remember, I suspect that I heard a bad pair so I'm not bashing the product, but - off my experience - this is one item I wouldn't touch til I got satisfied that the poor sound at audition was the fault of the sales staff rather than the speaker.

I have to agree. Those things are way too expensive for what they give you. If you want a high end, lifestyle type speaker, look at Meridian. That kind of speaker wouldn't be my first choice, but there's no compairson. I don't know what you are used to for music as far as equipment goes, but if you are not a hard core audiophile, you should be happy with them. For theater, they're great. You'll really like them for movies.
I sold a lot of B&O back in the day and I never liked their speakers. We usually sold ADS, KEFs, or Missions instead...

Most people just snob B&o because they see it as a life style kind of company and true, they don't focus only on speakers.

These beolabs absolutely need to be positioned away from walls more than you would with most conventional speakers, period! B&o marketing and awful showrooms want you to believe you can put them anywhere-not true. They need a large room. A small room is a big NO.
Set them properly and then you'll know what these speakers are capable of.

No speakers are perfect. Some speakers subjectively sound better than others. To me the beolab 5 (never mind the other speakers they make) are a work of art!
Think about the accomplishment: small package, 4 way speakers, wide dispersion, and deep deep bass. No need for subs, no need for fancy cables, no need for fancy amplifiers, no room for snake oil (which audio business is full and damaged from). It took B&o 6 years of research and development based on science!!
What I suggest is, do not audition them at their stores, ask them to bring the speakers home and set them in a large room away from walls as much as you can afford, and play music. You can directly send digital signal and you're set to go.