Yes.

Yes, the efficiency of the source is very important. For non-treble voices (basses, baritones, tenors) very little formant tuning is needed for most circumstances--there is enough spectral content available for the resonances of the voice to feature as formants. Primarily the /i/and /u/ vowels need opening much earlier than the others. Treble voices actively modify all vowels eventually in order to track whoop timbre (track the first harmonic with the first resonance--true "formant tracking."). Non-treble voices usually open /i/and /u/ to avoid whoop timbre unless they want a softer, sweeter expression. Back to the voice source, an clean, gentle, expression motivated coup de glotte, felt as if low in the neck below the larynx, with an expression-tuned pharynx and palate, will give a robust voice source. The back vowel examples in this video are all passive migrations or passive modifications--without shape change.

@@AcousticVocalPedagogy I see. Thank you very much for the detailed explaination!

You can’t mix M1 and M2

If you read the notes below this, you will see that this is a training tool to get competent but easy vocal fold closure--definitely not intended for performance, unless you are doing a character voice. It was however used in training by Gigli, Tagliavini, and other wonderful Italian tenors who definitely didn't sound nasal in their normal singing, though sometimes used it in sotto voce as in this voice-over recording (he's not in the picture--the actor is, but he is using pharyngeally colored sotto voce--but wait until he crescendos out of it at "si m'ama" to see how it set him up for full voice). The folds tend to remember the easy closure when you return to normal timbre. kzbin.info/www/bejne/ipqTc2ydjtiCn7c

very

Though you will likely get some frontal sensation, it is best if it feels like it originates further back, in the nasopharyngeal area, and, counterintuitively, a "warmer" version of the twangy timbre--in other words, don't drive the brightness forward into the nose. Go for pleasurable comfort and ease in the neck.

The perception of pitch comes from the second resonance peak as radiated in the second formant. Those second formants are high enough in pitch, and specific enough in tone color that we can all target the same "pitches" per vowel. Generally, if you get the target pitches I gave in the comments below this video--in a soothing, comfortable manner--you will have tuned the resonator well for that vowel for any pitches that do not require active modificaiton (active shape changing), which is most vowels at pitches below the first format pitch of the vowel being sung. And yes, you can aim for them, as long as you get them with ease and comfort.

@@AcousticVocalPedagogy Thank you. So it sounds like you're saying that practicing the chiaroscuro whisper at the pitches you recommended in the video details will help "tune" the vocal resonator for vowels that don't require active vowel modification, which are typically pitches below the first formant. Is that right? I'm curious what happens to the vocal resonator when you go above the first formant and start modifying the vowel, and what role practicing the chiaroscuro whisper has in that. Thanks again for your reply.

See this one: kzbin.info/www/bejne/b3KyaYuYnK6gebs

I constantly use what you taught me. Whenever I sing I feel you behind me.

This was not forced at all--quite comfortable and in fact easy. Yes it does passively cover. He was not a light tenor, rather a somewhat fuller voiced tenor, hence the slight baritonal timbre.

@@AcousticVocalPedagogy frankly speaking tenor’s voice is not heard in there just in the case of such a strange way of passageing I suppose it’s got to be covering and focusing a little bit closer for lighter sounding in the tenor way

The acoustic interactions are somewhat complex. the main take away is that if you want the voice to "turn" where the vowel would normally locate the first resonance, you should maintain the shape, leaving that resonance where it is in resonant speech, which allows harmonics to move through it as you ascend. The vowel timbre will then necessarily migrate or passively modify with that transition. Avoiding that turn results in a more yell-like timbre, caused by opening the mouth more and larynx raising. Using expression/affect can assist in avoiding excessive dulling (over covering) of the sound above the turn, by keeping inner height in the naso-pharyngeal area--sometimes referred to as inner smile or inner pathos.

Unfortunately not. A health issue eventually intervened.