listening room (living room) room mode problem

Hello everybody. I will try to follow the rules, and I appologies for my english (i'm from france). I have learned a lot with the help of this forum, and now I would like to make some "tuning" of my listening room. First, the concerned room : 9m x 3,5m x 2,6m so in feet approx : 29,5 x 9,9 x 6,6. walls are rock with plaster,and painted (it's an old house) ceiling is wood slats with plaster on it and between slats, and floor is wood, no carpet (maybe i need to put one?) the room is "virtually" (no wall) separate in two parts, the music place, and the library / quiet place. I have made a lot of measurements, with REW, and an apex220, and checked SPL at the problematic frequencies all over the room. The problem I have (I think) is the 38Hz mode, i suppose if i "kill" this 38Hz, I also kill the 57, 76, 95, and the 133Hz,This one is the most problematic for me because it's not only front to rear wall, but also right to left wall. I don't have a lot of space, there is no space between speakers and front wall (but i think i can find around 3" to 4" if it's necessary), and I can't make very big bass traps because it's a living room, not a studio (my wife say that :) ) There is a door on the left, just near the angle formed by the walls (45cm from the front wall) And there is a windo just on the right of the listening spot. I will try to make a plan if necessary. I plan to make all the needed treatment with the minimum money (i'm not the only one i think), all DIY. What do you think I have to make first? absorber on ceiling? superchunk in corners (but they will be mini superchunk)? I think I will try cotton fiber, I don't like glass fiber. impossible to upload mdat on the forum. https://www.dropbox.com/s/snv1tihw53cpz ... .mdat?dl=0 Thanks.