vibration

[Solve et Coagula]

"while you breathe it out through the nostrils with the air which has been till then retained in the lungs." (Liber O, III)

Do you use your vocal cords?

[Jim Eshelman]

@Jackdaw said

""while you breathe it out through the nostrils with the air which has been till then retained in the lungs." (Liber O, III)

Do you use your vocal cords?"

There are different techniques. The answer for this is "usually yes, but there are techniques that do not."