I have them 39" out from the front wall and if I pull them out more I start to lose body quickly...
That sounds about right for loss of mid bass - you will have a big suckout around 100 Hz - see the red curve.
That is why I soffit mounted my speakers - it is a universal problem but nobody seems aware of it.
You can move the speaker to shift the suckout to a part of the spectrum that bothers you less but it will still be there - unless you soffit mount.