Hi Greg,
Thanks for your answer.
It helps me a lot because when I see your videos, it seems to me that your low c is very louder than the next notes even with a low c#. For me it is not like that. when I let go passively my breath, the low c is loud and the next notes also, until C on the staff. So now, with your return, I think I have understood well your system and be on the right track.
Kind regards.
Francis.