Is this done with more bass trapping? I have not yet
trapped floor - wall corners.
Basically yes and for your room make them as large as possible. You will only get a square room so far. In the end you will know how well the room is when you do a mix. Either it translates well on other systems or not. That truly is the test of all tests. . I went though your build thread and did not see anything about the back wall. I might have missed it, but you want THICK absorption in that area also.
Yes, there are three panels on the back wall. The same as on the side walls.
I will do more bass trapping.
About that that lull from about 1800hz -5k. How do I address that issue?
I have no carpet on the floor in the listening position.
I have not bass trapped any floor - wall corners.
I have the possibility to add to more panels on each side wall.
I have the possibility to add two more panels on the back wall.
There is no quick or packaged answer. I do agree making sure your mic is performing accurately maybe a good place to start.
Otherwise, try changing your setup. Moving speakers farther apart, farther from close surfaces, enlarging your triangle, downsizing your triangle, changing the toe-in, changing speaker and/or listening height.
I am measuring using both speakers at the same time. Should I not?
I have now added one more panel on each side wall and added a rug under the listening position. I addition I added a little bit of bass trapping floor to wall on the back wall (I will bass trapp more, but didn´t have more at the moment).
The blue is the new graph.
I also see that the decay below 100hz have been shorter. It also seems like something positive thing has happened to 1800hz -5k.
According to this article on Real Traps you should use both speakers at once (and it says it is a good idea to also do each speaker seperatly).
The opposite is the normal procedure: measure each speaker separate but combined might also be useful but normally not needed. If 2/5/7 (or whatever) .1 systems, you naturally want to measure each (or at least L&R) speaker with (and possibly also without) the subwoofer.
An issue like this is getting a bit out of my area of knowledge, but its probably some sort of oscillation or resonance.
You get that wavy nature when a freq bounces back and forth between two surfaces. Their maybe other causes as well. When you added some more panels, you got those 1.8-5k frequencies responding higher, but there is something going on and I suspect a better more broadband absorber may help things. The panel you are using I suspect is only partially mitigating the problem.
I have now added more bass traps and two more panels on the side walls. It seems like the bass trapping again made the low end decay shorter, but except from that, the graph seems more or less the same to me.
I will add even more bass traps during the weekend which means that more or less all corners will be covered top - down (wall - wall, wall ceiling, floor - wall).
The name of the pictures tells if the graph/waterfall is left, right or both speakers (I see the whole name when I open them).
Red = Left speaker
Purple = Right speaker
Green = both speakers
Keep in mind that getting a room +/- 7 db or so is considered pretty darn good and you have a small, close to square room so it might be about as good as you can get. The key is to reduce decay times which is more important, IMHO. Getting the decay times in line on the low end will result in clarity.
Okey, but +/- 7 db, a 14db deviation is good if understand you right Glenn? So if I get the low end decay in line, my room is in pretty good shape given the shortcommings of small room like mine?
How good something is based on its context. Small rooms with less than ideal dimension ratios are harder to deal with than larger rooms with more ideal ratios. Thus, +/- 7db is good, considering your constraints, but not ideal. +/- 5db would be better, +/- 3db approaches as good as anyone gets in any room @1/24th octave measurements.