[Geoff St. Germain]

Room gain is dependent on the size of your room, which makes it hard to write a description of the ideal anechoic response that will create a flat response in room to some desired frequency. The smaller your room, the more room gain you will have (and the higher the frequency it will begin at). Cars have cabin (room) gain that can start near 100 Hz and on the other side of that we have outdoors, which offers basically no room gain.

Of course, I would prefer to have a frequency response coupled with room gain that makes the in room frequency response rise at the low end and have to cut low frequencies than have the reverse situation and have to boost low frequencies to achieve the same response (and deal with decreased headroom at low frequencies).