This right here is great advice.. If you just push that 400hz up blindly it may lead to an unnatural chesty sound..200-400 Hz is a very difficult area, its hard to do acoustical damping thats effective and its hard to do dsp corrections from the listening position because its near the transition area . This is where correct installation of the speakers are important. You can play with the distance between the speakers and the distance from speaker-frontwall. If you have the listening sofa against a wall, you can move it forward 30 cm or more, and the sound will be better.