If you are in, say, the lower register and push the voice up in pitch, at a certain point you will not be able to go any further in chest voice but must all of a sudden shift, not only to a different vocal cord thickness but, in keeping with what we've said, to a [...]
Exercising the Registers of the Voice
Another 'superstition' that should be mentioned concerns the current belief that 'registers' should never be practised separately because it leads to a so-called 'register divergency', i.e. 'an unhealthy separation of the registers' which will eventually prevent them from blending. A reminder: the optimal, the physiologically correct tone, is produced by the mutual, unified functioning of [...]