Did you ever buy too much bass?

@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. :)

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.

@tomcarr 

My best experiences have been with "middle-of-the-road" sound systems.  The Bose in the Audi and JBL in my current Toyota are probably the least offensive sound systems I've heard in premium cars.  The B&O option in the Audi hurt my ears.

@curiousjim  Your efficiency at 20Hz must have been pretty incredible.  😂 Guess you really did pressurize the room.

@deadhead1000  - That was excellent advice.  In your room I'm  sure you are getting down to 16 Hz.  :)  The JL Audio DSP software is just absolutely outstanding.  I'm not at all surprised, but ouch, the cost... 😂