This is cool! There's a lot of bad (and by bad, I mean misaligned with modern voice science and science-informed pedagogy) on the internet, so it's nice to see a resource striving to organize some good information.
A couple recommendations I'd suggest exploring to be even better aligned with current understanding:
Current literature does not distinguish between head voice and falsetto. While "falsetto" often carries a connotation of breathiness, that is not inherent to the register. Both are referred to in literature as laryngial mode M2, in which the Cricothyroid muscle is dominant in shaping the vocal folds. In contrast, chest voice or M1 is Thyroarytenoid dominant. While that may be a bit in the weeds, I found wrapping my head around this very helpful in cutting through a lot of confusing language around head voice .
Use of these different registers changes across genre and voice type. Classical sopranos and mezzos use head voice in their upper range, while musical theatre sopranos and mezzos bring their chest voice up (i.e. belting). Meanwhile, tenors and basses typically use chest voice for their full range in both classical and musical theatre genres, with much more use of head voice in pop/contemporary genres.
One other suggestion is to more prominently feature SOVTs (semi occluded vocal tract exercises). You reference them in your warm up section (lip trills and straw phonation) but these are highly effective and evidence-based tools to develop efficient phonation.
Further, for anyone looking to learn to sing (and anyone can learn to sing!), there's no better resource than a voice teacher. Most teachers nowadays teach online as well as in person. A great place to start looking for a teacher is through NATS or ICVT.
> Current literature does not distinguish between head voice and falsetto.
Hmm, are you sure about this? I thought chest voice and head voice were understood to be a single register called the modal register. And falsetto was fundamentally different.
Yes, though again, the language around registration gets really messy. Here's a great article (with a great title!) from the Journal of Singing by Christian T. Herbst "Registers—The Snake Pit of Voice Pedagogy": https://www.nats.org/_Library/JOS_On_Point/JOS-077-02-2020-1...
One relevant excerpt before the article goes into several pages discussing M11 vs M2:
> These four laryngeal mechanisms are typically termed as: vocal fry (M0, pulse register); chest voice (M1, modal register); falsetto (M2, head voice?); and whistle register (M3).
Another article by Dr. Ingo Titze (an icon in the field of voice science and basically the father of SOVTs) about the debated "mix" register, starts this way:
> One is called chest voice, full voice, or modal voice, which is described by a vibratory mechanism that some have labeled M1. Acoustically, harmonic energy above the fundamental dominates the sound spectrum in this register. The other anchor is called falsetto or light head voice, which is described by a vibratory mechanism labeled M2.
(from https://vocology.utah.edu/_resources/documents/mixed_registr...)
Thanks for adding your thoughts. First tenor here with a high C+ when trained and active. I lost my (true) falsetto 10 or so years ago, any tips on how to get it back?
Also I lost my whistle register 30 years ago, but I think this is normal :)
Yes! This is something I've been working on - not for the sake of the M2 mode itself (head voice / falsetto), but because M2 development tends to help with high notes in M1. When I started studying with my current teacher, my M2 felt somewhere between absent or very weak.
Typically exercises I work on for M2 start with an SOVT (typically straw phonation, puffy cheeks, or water bubbles) and then transitioning to an [u] vowel on a five note descending scale. For me, at least, while this can be very unstable depending on the day, M2 is much more easily accessible with an SOVT.
You might also start with a gentle SOVT in M1/chest and siren up as high as is comfortable without pushing/pressing or trying to be loud. Don't think about registration, just let it go - SOVTs tend to let the voice go where it wants easily.
Highly recommend my teacher's book: https://www.pluralpublishing.com/publications/a-systematic-a...
Thank you for the feedback, caryme.
And big yes - there is no better ressource than a voice teacher!!
This is just a lookup tool (and then some)