A vocal register is a range of tones in the human voice produced by a particular vibratory pattern of the vocal folds.
 These registers include modal voice (or normal voice), vocal fry, falsetto, and the whistle register.
A voice type is a particular human singing voice identified as having certain qualities or characteristics of vocal range, vocal weight, tessitura, vocal timbre, and vocal transition points ("passaggio"), such as breaks and lifts within the voice.
 Other considerations are physical characteristics, speech level, scientific testing, and vocal register.
 A singer's voice type is identified by a process known as voice classification, by which the human voice is evaluated and thereby designated into a particular voice type.
 The discipline of voice classification developed within European classical music and is not generally applicable to other forms of singing.
 Voice classification is often used within opera to associate possible roles with potential voices.
 Several different voice classification systems are available to identify voice types, including the German "Fach" system and the choral music system among many others; no system is universally applied or accepted.
"My Friend" is a song performed by Croatian singer Jacques Houdek.
 The song represented Croatia in the Eurovision Song Contest 2017.
 It was released as a digital download on 2 March 2017, and is the first Croatian entry to contain lyrics in the Italian language.
 Houdek alternates between singing in Italian using his chest register and in English using his head and falsetto registers.
The bass singing voice has a vocal range that lies around the second E below middle C to the E above middle C (i.e., E–E).
 As with the contralto singing voice being the rarest female voice type, the bass voice is the rarest for males, and has the lowest vocal range of all voice types.
 However, the bass voice is determined not only by its vocal range, but also by its timbre, which tends to be darker than that of a baritone voice.
Falsettone is a term used in modern Italian musicology to describe a vocal technique used by male opera singers in the past, in which the fluty sounds typical of falsetto singing are amplified by using the same singing technique used in the modal voice register.
 The result is a bright, powerful tone, often very high-pitched, although the sound is still different from and more feminine than what is produced by the modal voice.
 The term "falsettone" is also used for the mixed vocal register that can be achieved using this technique.
Georgia Brown, pseudonym of Rossana Monti (born June 29, 1980) is an Italian Brazilian singer noted for her extensive vocal range.
 She was listed in the 2005 "Guinness World Records" for hitting the highest vocal note and for possessing the greatest vocal range for a female, claimed to be exactly eight octaves from G-G using scientific pitch notation.
 However, as of 2013, Tim Storms holds the record for the widest vocal range of any human with 10 octaves.
The vocal fry register (also known as pulse register, laryngealization, pulse phonation, creak, croak, popcorning, glottal fry, glottal rattle, glottal scrape, or strohbass) is the lowest vocal register and is produced through a loose glottal closure which will permit air to bubble through slowly with a popping or rattling sound of a very low frequency.
 During this phonation, the arytenoid cartilages in the larynx are drawn together which causes the vocal folds to compress rather tightly and become relatively slack and compact.
 This process forms a large and irregularly vibrating mass within the vocal folds that produces the characteristic low popping or rattling sound when air passes through the glottal closure.
 The register (if well controlled) can extend far below the modal voice register, in some cases up to 8 octaves lower, such as in the case of Tim Storms who holds the world record for lowest frequency note ever produced by a human, a G−7, which is only 0.189 Hz.
 Humans however can only hear sounds down to 12 Hz under ideal conditions.
In vocal music, the head voice, depending on vocal pedagogy, is a particular part of the vocal range, or type of vocal register, or a vocal resonance area.
Falsetto is the vocal register occupying the frequency range just above the modal voice register and overlapping with it by approximately one octave.
 It is commonly cited in the context of singing.
Falsetto ] (Italian diminutive of "falso", "false") is the vocal register occupying the frequency range just above the modal voice register and overlapping with it by approximately one octave.

Question: What part of the vocal register does Hoedeck alternate with falsetto, that uses a particular part of the vocal range?
Answer: the head voice