A majority of rooms introduce a mild shelving at the lowest frequencies in room, often equaling a 6dB/octave 3-5dB boost. I recently placed a pair of “full range” speakers in my room (-3dB @32hz), and noticed in measurements the low end was bumped up by about 5dB in measurements. After running Audyssey XT, the corrected response measured fairly flat in comparison, but upon listening and switching between Audyssey on vs off, I immediately noticed the “corrected” response sounded completely unnatural, low notes from a bass guitar sounded thin and weak, whereas the uncorrected response sounded full and natural. Simply crossing the speakers to a sub and boosting the level by a few dB didn’t solve the problem, it just resulted in boomy sounding bass.
I started researching this effect and found that several studies done by harman showed that removing the room gain from the low frequencies in various room correction software resulted in poor subjective performance, resulting in the change being rated as “thin” , “bright” and “harsh”. Based on the results of this, harmans room correction target curve incorporates a slight shelving of bass similar to the effect of boundary gain.
Digging deeper, it’s also interesting to note, that many headphones designed for accurate studio monitoring also incorporate a LF shelf similar to room gain. Three examples here
Considering this, should we really be attempting to completely flatten the bass response? It seems to me, that outside of some minor attenuation of unruly peaks, some amount room gain should be mostly left in tact.