Hi Bertru,

Mixing bass frequencies "one can’t hear” is quite difficult
but a very common problem IMHO. Your ”backing-the-chair-trick” indicates you have a possible front-back room LF reflection problem which is also shown in your REW plot.

Suggestion for a start:
1. Run an ordinary measurement as is. Your usual LP and spkr positions.
Note: Measure L&R speaker separately. So we can compare L& R!
Your L/R room is different and that will change measured L/R response.

2. Move loudspeakers as close to the front wall as possible.

3. Move mic forward to the new provisional LP.
(You don't have to move keyboard etc for this quick test)

4. Measure L& R again. Better?

5. Uppload mdats here and we can take a closer look.
Note: There is a restriction in file size ≈10MB. You have to upload smaller chunks.

Good Luck

Great! I downloaded it and the data looks valid... And it also shows that your room is going to need a lot of attention, to get it good. Right now it's too dry in there (decay times are too low overall), indicating too much absorption... but at the same time, there's not enough Bass trapping. Decay time for that size room should be around 210 ms, but it's only around 165. However, most of that is modal stuff on the low end, that sort of skews the total. Across the mids and highs, your decay time is only around 145-50 ms. I would expect that it sounds a little dull in there? What treatment do you have in there? Just the foam on the walls? It is not doing you any good at all. Dump it.

I also suspect that the floor might be carpeted? It's hard to figure out from the photos, but the REW data suggests there's something thin sucking out the highs. It might just be the foam, but it could be carpet too. If so, that's probably a part of the problem. If that's the case, I'd suggest either taking it out or covering it over with harder flooring.

The modal issue are pretty big, so you are going to need some major Bass trapping in there. You seem to have some tube traps in there: what exactly are those?

However, I'd also suggest that, first of all, you should re-orient your room if possible, either 90° left or 90°, so it faces towards the bottom or top of the page ("Bay Window" or "WC Door"). The best option would be having the speakers on the wall that says "WC Door", then use most of the bay window for Bass trapping. But I'm not sure that would be feasible, to fit the speakers in comfortably.

The reason for this suggestion is because right now only have about 1.5 - 2m between your head and the rear wall, which isn't enough. Facing the other way would give you a larger distance, probably a meter more. Still not a lot, but better. You also have your head pretty much in the middle of the room, which is about the worst possible place: It's a peak for some modes, and a null for others.

If you can't change the orientation, then all is not lost: You will just need to treat the rear wall even more aggressively.

You have two panels marked "bass trap" between the speakers and the front wall, but they are not very big, as I already mentioned: those need to be wider.

So my suggestions would be:

1) Re-orient the room to get the speakers firing down the long axis.
2) Lose the thin foam on the walls.
3) Lose the carpet (if there is any), and have your floor hard and reflective.
4) Build large, deep Bass Traps in as many corners as you can manage, using OC-703 or some such, but with strips of thick plastic across the front up high and down low, so as to not such out too much of the high end.
5) Fill the rest of the rear wall with deep absorption, all across. You don't have enough space for hangers, so just 15cm of OC-703, once again with wide strips of thick plastic over the front, or perhaps wood slats, but not at ear height: near the top and bottom only
6) Put your speakers up against the new front wall, with larger absorption panels between the speaker and wall.
7) Get the mix position about one third of the distance between the front and rear walls.
8) Aim the speakers at a spot about 12" - 18" behind your head. Don't worry if the speaker angle is not 30°: anything between about 25° and 35° is decent.
9) Put 10cm porous absorption on the side walls at the first refection points.
10) Hang a cloud above the desk. If possible make it hard backed and hang it at an angle.

That should get you a room that is considerably better than it is now, and hopefully it will be far enough along that you can use digital tuning for the final tweaks.


- Stuart -