The "Fletcher-Munson Curves" Reverberation Tutorials bellow will explain why your under damped huge room has no bass.
First note that a comfortable average loudness level of 80 db-C is typical, but perceived loudness depends on two items.
#(1)The sound pressure level(SPL), and #(2) the duration of the sound as defined by the reverberation time constant(RT60)which adds "very loud" duration to the audio signals.
In your live room the RT60 time constant may be as high as 3 seconds which will increase the perceived mid frequency spectrum loudness by as much as 25 to 30 db due to the reverberation duration which continues to stimulate your hearing, forcing you to reduce the volume at least 20 or 25 db, which according to the "Fletcher-Munson Curves results in approximately 30 to 40 db decrease in perceived loudness of the bass.
The Tutorials on #(1)Reverberation & #(2)The "Fletcher-Munson Curves"
#(1)...In acoustics the reverberation time at a particular frequency is defined as the time taken for sound to decay by 60 dB; often abbreviated "RT60" or from the first 20 dB or 30 dB of decay [T20 or T30]. If the overall RT60 is more than 1.5 seconds, the room acoustics will be "live" and echoy.
Too little reverberation and sound does not travel well throughout the room ,& the acoustics are dead and rather unpleasant. Too much reverberation and clarity is lost in a confusing "mish-mash" of echos.
"The optimum reverberation time is given at 500 Hz. Important for music, the reverberation at low frequencies should be increased so that the time constant at 125 Hz is up to 1.5 times the value at 500 Hz.
#(2)...The Equal-Loudness Contours often referred to as "Fletcher-Munson curves" were developed by Bell Laboratory researchers in the 1936 Worlds Fair on some 1000 hearing subjects. Loudness levels are arrived at by reference to equal-loudness contours of sine waves of differing frequencies. An equal-loudness contour is a measure of sound pressure (db SPL), over the frequency spectrum, for which a listener perceives a constant loudness.
You can see here that "Perceived Loudness" depends on the SPL of the sound, and as the SPL decrease, the perceived loudness of frequencies below 1,000 Hz, decrease rapidly while the midrange loudness remains proportional to the sound level pressure.