New room, new challenge

[thexder]

Hi, fellow audio friends,

I recently had to say goodbye to my beloved old room and am now starting fresh in a new space.
I’ve done some early measurements while the room is still mostly empty. There’s no acoustic treatment yet. Just exposed (unfinished) walls to allow access to the primary insulation (6"), and a perforated ceiling with roughly 20" of thermal insulation above it.

I’m still learning how to properly interpret the graphs, so I’d appreciate some feedback.
SPL seems fairly straightforward, there are some dips that I assume could be addressed with more traps / broadband treatment. What puzzles me is the group delay, which looks strange. Could this be caused by sound leakage or some kind of measurement artifact?

The main thing I’m noticing by ear is weak bass (the speakers are fairly big with 12" units and go down to 30 Hz).

I’m happy to share more room details, photos, or if that would help. I did a sim and it looks similar to measurements.

Thanks in advance!

 

[Todd Anderson]

Hmm... is your seating position in the null at 30Hz?

 

[thexder]

Hmm... is your seating position in the null at 30Hz?

Not quite sure but I can move the pic around and see what happens.
Seating position is flexible as the room isn't yet finished. Moving it in the simulator doesn't do much.

I spent some more time in the simulator and noticed a really interesting phenomenon. The graph "sim11" uses a parameter of 0.2 for absorption. In the second one ("sim22"), I added maximum absorption to the front wall and 0.5 to the side walls and it smoothed things out quite nicely.
What surprises me is that if I set both the front and rear walls to maximum absorption, the result actually gets worse in the range above 80 Hz. Below that, it smooths out a little more.

Anyway, I somehow lived with the belief that having enough thickness on all walls is ideal for the entire spectrum - at least when it comes to controlling LF.