So in posting this I was interested in either confirming or disproving that supposition. But only to a very limited extent as it's not a perfect scientific situation. As you say, it should be relative to an uncoloured, unmiked sound. Which would also need to be with your ears at the same distance from the saxophone as the microphones to be a more perfect test, so that the actual room ambience wasn't colouring the sound.
Still, at the end of all this, I guarantee it will have been a useful and for many people surprising conclusion.