Is that really true that putting "your light source closer to your subject, makes the light much softer"? I thought it was the opposite.
As well as the intensity increasing, there's also the effect of the Inverse Square Law making the fall off sharper, which can make it seem like the light is harder.
But for the quick and dirty experiment with 'large close soft' and 'distant point source' try this.
Photograph model 2" from a window with a diffuser (voile) take subject outside on a bright day lit just by the Sun.
You don't have to do that experiment, just imagining it gives the answer.