Room correction with D400 and B&W 800D

[Soniclife]

That's the 'flattest' in room response I've ever seen without applying serious DSP for room correction. I'd say it's almost impossible unless your system is outside, in an anechoic room or a VERY well treated room. I doubt the measurement is correct unless you've put some serious effort into treating the room. If all checks out right, hats off!

I've never seen anything that flat published online either, even with room correction!