Even half of a DBA is going to have some benefits, it requires 4 subs stacked up front.
Often where the subs will sound-best is where they will look-ugliest, or you'd be walking on/around it. Rarely does subwoofer-placement measure nice and look nice at the same time.
People often place their subs next to their front speakers, and rarely does that turn out to be optimal, but it looks the cool!
You'd think having subwoofers placed far away from the fronts would be bad, and some times it is... but more often it isn't. Trust the measurement charts.
There is no such thing as the perfect room.
All rooms / placements have nulls, it's just a matter of where, at what frequencies, and how-bad.
Usually it's about minimization, not cure.
Peaks can be tamed with EQ, nulls can't.
That said: an anechoic chamber measures perfectly-flat, and sounds perfectly-horrible. Ears/Brains aren't measurement mics/charts.
HiFi comes at a price, and I don't mean money.
and once you hear better, there is no going backwards either.
The rabbit hole is deep and steep and slippery. Careful what you wish for.