Vocal Type: Light-Lyric Soprano [3 Octaves and 1 note]
Vocal Rating: C
Positives: Instantly identifiable voice, with a fast vibrato and original rasp contributing to this. Able to sing complex melisma with great agility (see the head voice riff in Elastic Heart). Her low notes are not hit by lowing the larynx and have a dark quality to them, though they are easily the weakest part of her range. The mid-range is strong, as well as chest voice notes up to C5. Her head voice is sweet and feminine. Her phrasing and tone are original and instantly identifiable.
Proficient with legato phrases. Her voice is able to adapt to different genres in the pop field, such as disco, pop/rock and EDM. Able to execute growls without strain.
Negatives: Upper chest voice belts (those past Eb5 usually) are horribly strained and pinched, and are never mixed, leading to cracks. Her voice cracks, though they appeal to some, show signs of vocal damage either due to substance abuse, poor vocal technique, or both. She also utilizes vocal fry very often, though this could also be seen as an emotive positive.
Her vocal range on 1000 Forms of Fear, Bb2-Bb6
Notable mention to oziroxxmisoxx on YouTube for a strong write-up on Sia's voice.