"My question is How does this explain single mike recordings?"
Typically, the mixing/mastering will run the entire two channel mix down though a stereo processor and this will give a 3D quality even if the track was mono. Another technique often used is that, unless live, many vocalists double track the vocal to thicken it. A small panning L/R of these two mono tracks will create a huge 3D effect. Some are better than others at achieving such vocal reproducibility. In the digital world, one can also copy a mono track and then provide slight reverb or delay with different settings to each of the two mono tracks and then, again, slightly pan L/R each mono track to create the 3D effect. I’m sure there are many other methods (tricks) that are commonly used to create such depth.
Typically, the mixing/mastering will run the entire two channel mix down though a stereo processor and this will give a 3D quality even if the track was mono. Another technique often used is that, unless live, many vocalists double track the vocal to thicken it. A small panning L/R of these two mono tracks will create a huge 3D effect. Some are better than others at achieving such vocal reproducibility. In the digital world, one can also copy a mono track and then provide slight reverb or delay with different settings to each of the two mono tracks and then, again, slightly pan L/R each mono track to create the 3D effect. I’m sure there are many other methods (tricks) that are commonly used to create such depth.