Did you ever buy too much bass?

hi @kokakolia  - It sounds like your problem is room modes.  You need a DSP before your sub to clip the peaks off, then you can integrate, and raise the volume of the sub to match your mains.

My suspicion based on your symptoms is that you are compromising the volume of the sub because you have particularly hot peaks that prevent you from turning it up properly.

Besides measurements and getting an EQ, consider the AM Acoustics room mode simulator.  Try to keep your sub out of the first few room modes.

I put a Swarm in my VW van and us it to extract revenge from those young upstarts  when we are at a stop light. 

@erik_squires Thanks! I have my sub in the worst spot according to your web tool. I live in a flat, so space is at a premium. I guess I could use the sub as a footrest or a low side table? 

I thought I could EQ with the Bluesound Node 2021, but I messed around with the app several times and I can't figure it out. My amp has basic treble and bass adjustment, but not a real EQ. 

@kokakolia

Strongly encourage you to move the sub first. Then it’s pretty easy to view the problem using the right tools like Room EQ Wizard and a calibrated mic or OmniMic.

If you don’t want to move the sub, you might try EQ route first.

Measure the sub alone first, and clip the peaks. Then try to get a descending slope from 20Hz to 100 Hz or so, about 1.25 to 1.5 db/octave. Then set the crossover frequency for smoothest transition.

If you had not said space was at a premium I'd suggest corner bass traps/soffit traps as great additions.  Maybe your next place. :)

Thanks! I just moved in LOL! To be frank the sub is almost always off. But when I have the time during a weekend I'll definitely move the sub around.