my tweakend

[thumb5]

antoine thats my lovely rooms modes!

nothing to do with the subs gain unfortunately

the new room will have enough treatment to combat this

Are you sure it is a room mode? As I mentioned it looks to me as though it's a result of placing the microphone too close to the back wall. At that position you will see an excess of bass due to constructive reinforcement across a band of frequencies (that is, not a room mode as such). Having said that, if that's your listening position you can maybe treat it in a similar way to a room mode anyway.

[completeluxury]

its actually about 1.5 mtrs off the back wall, the mic is placed in front of the couch not where your head would be if you were sitting in it.

the room is the right length for a 40hz mode, the 20hz bump might be because of how far back it is but ive moved the mic even closer to the front than it is there (about 2m off the back wall) and the same result with the 40hz mode.