Vinyl trouble Part 3: Boomy sound

Might I suggest a simple test that requires changing nothing.

Play some of the music that exhibits the problem described, whilst it is playing, move around the room while listening to see if it is worse at some places than at others.

If this is the case, that it is worse at some places and not at others, then you have room generated reflection problems and repositioning the speakers may alleviate the problem, at least WRT the normal listening position.

It may also suggest the use of absorbtive panels, bass traps etc to help tame reflections.

Particularly if your speakers are rear ported, then those glass doors behind them will not be helping, even if they are not, I would still be trying them further into the room, at least to the edge of the carpet and from the apparent distance of your listening position I think I would also reduce the "toe-in".

I would not have thought central heating necessary in Haiti.   Live and learn eh