Several comments:
1) Taking the -20 dB line as the point of reference, which seems to be how the software is set up, those peaks and nulls are only about 6 dB up or down, which is not bad at all for a control room.
However, the REAL average seems to be more like -23, meaning that the peak is about +9 dB.
2) On the other hand, that graph does show 1/3 octave smoothing, so the actual REAL peaks and nulls are probably much bigger: you should show the graph with no smoothing at all, or 1/48 octave smoothing at best. Any more than that, and you are hiding the modal issues.
3) The graphs are showing the entire spectrum, which is not much use for seeing modal response issues! Zoom in to show just 15 Hz to 500 Hz. That's all you need to see for modes.
4) Next, this is for a control room, right? If so, the measurement should be taken at the mix position, not close to the rear wall. The measurement mic should be located exactly where your head will be when mixing, and nowhere else. That's the point that matters. The response will ALWAYS be different at other locations in the room, no matter how much you treat it. Bass will always be more pronounced closer the walls, comb filtering will always be present close to windows, etc.
5) Assuming that the numbers on the lower part of the right axis are milliseconds, that room is way too dry and over-damped already. The overall decay time seems to be around 40 ms, which is very short for a control room. I would be looking to increase the liveness, by covering some of the absorption with reflective surfaces. Perhaps slot walls, or even diffusion if the room is large enough for that,
I tried to add 2M2 of tuned traps
What type of trap, and how did you tune it? The frontal area of the trap isn't that important: the volume of the resonant cavity is what matters most.
Do you think this could be adressed with paneltraps or limp membrane? Or is an active solution maybe a better idea?
Active systems generally only work well for specific locations in the room, and are rather expensive, as well as being difficult to install and tune correctly. What other treatment is already in the room? Please also provide some photos of the room, and use REW to to the testing. Then post the MDAT file here, so we can download it and analyze it in detail.
- Stuart -
But i want to make it more even so the severe nulls are more smoothed out.