Jessie J has ability to sing complex melisma without issue, and this is often noted as being a signature of her style.
She can hold notes for lengths of time without loss of quality to the sound, and sing complex and lengthy vocal lines in a single breath. She has strong mid-range that is solid, has a good dynamic to it and leads into the belting range effortlessly. Her technique sounds improper when reaching high notes and as a result her voice becomes unstable.
Adam Lambert has expert control over his instrument. He produces notes that are well supported with good technique. He is capable of singing complex melisma and is able to hold notes for period of time without wavering in pitch.
His lower range is dark and weighty. He also has a piercing head voice but at times, when he goes very high notes, it sounds a bit shouty to me.
Leona Lewis is a brilliant / technical singer and her voice has an overarching sweet and light tone. She sings complex melisma and stamina to hold note very easily. The texture of the mid-range and the head voice can be alternated between a smoky timbre and a clearer one depending on choice.
She controls the low notes a bit shaky and sometimes higher belted notes are reached without mixing to a harsher tone. The vibrato can also sound clumsy at times.
Adele has unique soulful voice and her vocal type is contralto. Her low to mid range is rounded and solid with a soulful coloring. The lower part of her belting range is clear and bright.
Her head voice is thick and weighty with a warmth and resonance, but isn’t often used. When she sings, the notes that she produced are further improved by her quick and natural vibrato. She is definitely more an emotional singer than a technical singer.
Mariah Carey can able to sing from a crystal clear, high octave belt to an airy whisper within the space of a word. Her vocal...