Some Purring Progress

Last night I managed, while lying down, to reach a deeper inner depth for the purr/ snarl/rattle/flutter/smiling meditation. By 'depth'I mean literally as deep down into the chest as I could manage to resonate, and by smiling manage to keep the same pitch/tone on the inhale as the exhale. Of course the masters of this low-pitched growl are the Tibetan lamas, and I've often wondered, while listening to their inspiring recordings, whether their low pitch has anything to do with their attained experience. I am more and more convinced that it does, because the lower the pitch, the deeper into the body it resonates -- as anyone who has attended loud rock concerts can testify.
Ideally I think one should be able to resonate into the center below the navel, at least for starters.
If the trachea resonates, the aorta vibrates, and the heart as well!
Good vibes all 'round!