Voice type in baroque operas. Except for a few very rare voices (such as the American male soprano Michael Maniaci or singers with a disorder such as Kallmann syndrome), singers called countertenors generally sing in the falsetto register, sometimes using their modal voice for the lowest notes. Historically, there is much evidence that the countertenor, in England at least, also designated a very high tenor voice, the equivalent of the French "haute-contre". Until about 1830, all male voices used some falsetto-type voice production in their upper range. Countertenor voices span a broad range, covering E3 to E5. Countertenor subtypes: Countertenors are often
Estill Voice Training Jo Estill has described it as "happy yelling".' Belt quality also uses clavicular breathing and has the longest closed phase with the highest subglottic pressure and the greatest glottic resistance. Estill Voice International governs the Estill Voice Training Certification Programme. There are three forms of Estill Voice Training certification available for individuals: Estill Voice Training has been adopted by voice professionals worldwide and a list of certified instructors is published by Estill Voice International. Joan Melton describes the Estill Voice Training terminology as a part of the language of singing teachers in Australia, with terms such as twang and anchoring