I’m studying classical singing in a conservatory of music for only less than 2 years and am a soprano (I’m not yet sure which type). When I vocalize, I usually go up to A and sometimes B below the high C. But the thing is, I can also reach the whistle register from that very same A up to the high G but i don’t include it yet in the vocalization because it is a completely different feeling, one that is very light and effortless. It sounds thin and it doesn’t have body like that of my lower registers but I can easily produce vibrato with it. I haven’t told my teacher about this whistle register yet because I’m afraid that she would torture me to reach it with the same quality or thickness as that of my lower registers during a lesson. That’s what I’m not sure about–how do I make that whistle sound one with that of the lower registers? What specific types of vocal exercises could I use to smooth out the passaggio in this particular area? I really hope you could help me.
Thanks a lot.

Thanks for writing with your question. The first thing I would say is it all depends on the nature of how you are producing the whistle register. Often when people are able to produce this part of the range it can be used as a guide to the rest of the voice. I would suggest trying downward slides starting high in the whistle range and taking it all the way down to your lowest note. If the voice does not crack then that means you are in line and it is beneficial. If the tone cracks at some point that means the registers are out of line with each other because of misalignment in the vocal tract and this needs to be fixed before the exercise is worthwhile. This is often the case when we feel like we are singing out of the mouth. It is critical that we use all three pharyngeal areas for resonance to allow the voice the greatest flexibility and freedom. We use a little “oo” vowel to exercise this resonance coordination. Because the mouth opening is so small the tone is not allowed to escape and has the opportunity to resonate in the naso-pharynx in the head. This conditions the tone and makes it vibrant and full while being very easy. It is singing in the position of whistling. It takes some getting used to. Once we have the feel of singing in the upper resonator we can sing all vowels while keeping the resonance position.