Christina María Aguilera

Describing Aguilera's voice, singing teachers Phyllis Fulford and Michael Mailler said, "The low register is light and tired, the belting register is ample and full, but very scratchy because she screams; and head voice as well as whistle register are light, pure and bright. Her vocal range extends from G below middle C to C♯ one octave above soprano high C (G3 - C♯7). She can belt to F one octave and a third above middle C (F5). She possesses a good-sized technical arsenal. Her trill is solid, she has a big mastery of melismas, and can sustain very long notes." Los Angeles Times writer Margaret Wappler adds Aguilera can deliver "a well-executed legato." However, countertenor Philippe Jaroussky said: "She has no breath support and often sing out of tune. People say she can cover four octave, but it's not true because below A3, the low notes are forced, unsupported, her belting voice is throaty and forced and for her highest notes she doesn't use head voice but falsetto or whistle register, they are disconnected registers. So, she can hit good notes only from A3 to B4. Her melismas are always show-off, they are almost never connected with the rhythm and the structure of the songs."
Since her debut in 1999 Aguilera has been compared to the likes of Mariah Carey and Whitney Houston. David Browne of The New York Times writes, "Aguilera has been one of the foremost practitioners of the overpowering, Category 5 vocal style known as melisma. Ms. Carey, Ms. Houston and Ms. Aguilera, to name its three main champions, are most associated with the period from the late ’80s through the late ’90s." A review in the Los Angeles Times compared Aguilera's vocal stylings to Barbra Streisand, Gladys Knight, and Aretha Franklin adding, "Aguilera's Streisand-esque tendencies are a good thing; they're helping her figure out how to become the "great singer" she's been dubbed since she released her first single, the wise-beyond-its-years "Genie in a Bottle", at 18." Although praised for her vocals, Aguilera has been labeled for oversinging in her songs and concerts. Longtime producer and writer, Linda Perry, commented on working on the record, "Beautiful", saying, "I tried to keep it straight. I told her to get rid of the finger waves. Every time she'd start going into "hoo-ha", I'd stop the tape. I'm like, 'You're doing it again.'" Perry ended up using the first take saying, "She had a hard time accepting that as the final track. It's not a perfect vocal – it's very raw. She knows her voice really well, and she knows what's going on. She can hear things that nobody else would catch."
• Themes and musical style
The constant theme in Aguilera's music and lyrics is love, although she has written on other subjects including spirituality, female empowerment, and grief. Aguilera has also written about her childhood in two of her records which dealt with domestic abuse. In an interview Aguilera admitted she feels responsible to reveal her most vulnerable feelings and to share the darker sides of her life adding "People that can relate might not feel as alone in the circumstance." She has been noted to constantly changing her sound in her music and lyrical content. Originally marketed as a bubblegum pop singer during the late 90s pop scene, she quickly departed into a broad range of musical genres for her follow-up album Stripped. A review states, "Clearly afflicted with Premature Serious Artist Syndrome, Aguilera wants to demonstrate the range of her interests – vampy soul, quasi-metal, piano-bar intimacy, quiet-storm R&B, bounce-bounce hip-hop, and semi-exotic rock, all of it dutifully accomplished."