continued
In evitably there is speculation abouta subject that is by definition shroud mystery.

Look at the speculation that surrounds Robert Johnson's recording sessions where he sang with his eyes averted from the men who were recording him.
Some people say he was insecure playing to his social superiors.
Some people thought he was hiding his ,techniques from those who would steal his ideas.
Ry Cooder thought he was 'corner loading' - adding compression to the sound by singing directly at a wall.
I don't think we can be sure of the correct story. We simply weren't there.
In traditional music I have noticed people get very attached to their theories, which is okay if we use those theories to make decisions about performance.
But we all need to face the facts that what we create is a speculation .