Does the Devore Fidelity Orangutan 0/96 speaker play rich and full bodied at 50 Decibels

I have O/96 driven by an Air Tight 300B SET and routinely listen at 55-70dB (according to Apple Watch) with very compelling musicality.  Your hearing will attenuate the bass as volume drops, but the O/96 sounds very full from barely audible in my room at least.  On the other end, my 8W amp can drive them well enough to easily fill a roughly 15'x25'x10' with 100+dB.

Room configuration may play an important role to answer adequately. Having said that I listened to the 0/96 in a very large room and in a very small room and they were fantastic. In the large room they were paired with a Pass  Int 25 and in the small room with a Sugden A21 SE if my memory serves me well. It was more like at 60-65 db however. I am sure they will sound good at 55 db but you may not maximize their potential, like with most speakers I would say.

Listening at such low volume imo negates much of what High Fidelity is about, which is verisimilitude to naturally occurring musical sound, as recorded.  That said, the best listening experience will be obtained by using the known science of psychoacoustics and respecting the equal loudness effect.  A Yamaha R-N1000 receiver has more than adequate power amp quality to satisfy and it has a room EQ with a calibrated equal loudness function called YPAO Volume…and bass and treble controls to trim to taste. I don’t care how much money you spend on quality electronics, at low volume none of that will be as perceptible as properly done loudness compensation. 

I have an office system that is a near field setup and it never passes 55dbs, but in my main system, I average 65-75 dbs for full rich everything.  I would really enjoy hearing a speaker that sounds good at lower levels as the older I get, the more sensitive my ears are becoming to a specific upper midrange, lower high range.

The O/96 are among the best at low volume bass as long as your amplifier is robust and electrically compatible with them.  It is the amplifier and speaker combination that makes speakers pop at very low volume levels.