I understand. I know you do a good job. You are truthful and have helped numerous folk over the years. However I Quote again
"All of you need to remember that I am in the business of performing where every nuance of the tonal quality, clarity of the vowel & ability to sing on pitch + good diction, etc., is crucial."
It is not Rock and never will be. So in effect you are teaching how NOT to sing in a rock style. If you do not OR CANNOT change this ethic and the techniques associated with it then Blues or Rock singers will get very little if anything from formal recognised coaching. My argument is simple most folk will benefit from vocal coaching but if you want to sing Rock forget it. Name one Rock singer who sings using any of the above digeridoos from your quote. Name one vocal coach who sings Rock authentically whilst still maintaining clarity of vowels and good diction.
No further witnesses, I rest my case m'laud.

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