Monaural Hearing

The brain demonstrates remarkable powers of adaptation if given time to adjust. Although my hearing on one side is defective, the spatial stereo sound with headphones is central. The right channel is very quiet and essentially missing, though it 'sounds' OK. In most cases it is quite acceptable (as though I’ve got a choice!).

Since I hear only monaurally, and my brain has adapted to compensate so I perceive a normal stereo image, even though the sound source is essentially only in one ear, do I need to hear at double the normal volume to appreciate 'normal' sound levels?

I do seem to need higher than normal volume, although an actual doubling in volume does not seem to be the case. I suspect air pressure is normal in both ears even though sound is missing in one side.

I can demonstrate this to myself by listening to old stereo recordings that have distinct left/right channels for different musical instruments. Reversing the headphones changes the sound balance as other instruments are heard: channel-to-ear determines what is heard.