Sound is better when I stand up?

@simao    

I note you have removed the toe-in.  This is the purist position.  If the production was classic then there was a spaced pair of dipole microphones in front of the musicians.  If you don't toe-in you are hearing what the mics heard.  If you toe-in, the image of the sound will be spread outwards. A 'hole' may appear in the centre.

Speaker toe-in and listening distance are of course related.  Less toe-in is has a similar effect to listening from further away.

I do think you're making a mistake with the wingback.  If you like to rest your head perhaps a chair with a smaller headrest to the back of your head not impeding soundwaves' access to the ears.

Or listen with headphones?

Many reviewers like EXTREME TOE IN where the left speaker is aimed at your right shoulder and visa versa........It's an interesting sound...you should try it .

simao    

I note you have removed the toe-in.  This is the purist position.  If the production was classic then there was a spaced pair of dipole microphones in front of the musicians.  If you don't toe-in you are hearing what the mics heard.  If you toe-in, the image of the sound will be spread outwards. A 'hole' may appear in the centre.

Speaker toe-in and listening distance are of course related.  Less toe-in is has a similar effect to listening from further away…

I think that another school of thought is as the room get brighter in reflections, one may also chooser to toe them in.
Particularly if the speakers have a narrower radiation pattern.
If they are super wide, then the toe doesn’t matter at all.
But sometimes if they are bright, then toeing them out can reduce the direct SPL.

There is nothing seemingly pure or impure about it.
I thought it is like a tone control to tailor the speakers bespoke to the room the speakers are in.

Stand up sit down its fun.

There is so much truth to your statement @ebm.