What happened to my room acoustics

I measured the spectrogram for my room at my MLP, and the FFT results are as follows:

- There is a roll-off before 20kHz.

- A dip is present around 12kHz.

- There is a noticeable boost between 50Hz and 1.5kHz.

- The bass rolls off around 33Hz at -3dB, consistent with the factory rating.

Comparing these measurements to the Burchardt measurements, there are some differences:

- It doesn’t exhibit a roll-off before 20kHz.

- The dip is around 15kHz.

- The boost between 50Hz and 1.5kHz is not as pronounced as in my room.

I’m curious about what might be happening with my room acoustics. If a fix is possible, what would it entail?

Spectrogram from my zoom

My room / speakers setup

Measurements from Burchardt

lanx000311-03-2023 1:14pm

hilde45 Details Discussions Posts This discussion Message User 4,863 posts 11-04-2023 at 01:00pm Copy Comment URL Report Comment Edit Delete A few comments: Yes, move the seat forward. You’re probably hearing a lot from the rear wall you could eliminate by moving forward. My speakers are 8 feet apart and I sit 10 feet away. My back wall is another 9 feet behind me. Worth a try. Did I miss comments about ceiling height? Some of the worst reflections come from floor or ceiling. They may be interfering. It's very helpful to measure impulse responses to see how the reflections are, or you won’t get a handle on imaging and soundstage. Get those as many reflections between 4 and 12 ms down below -20db if you can. Viz. - There is a roll-off before 20kHz. - A dip is present around 12kHz. COMMENT: These are very high and likely won’t matter much. (In my view.) - There is a noticeable boost between 50Hz and 1.5kHz. COMMENT: Much more important.