f(x)’s Vocal Analysis: Krystal


Vocal Range

C#3 ~ C#6 (3 Octaves)

Supported Range

A3 ~ A4/Bb4

Voice Type

Light-Lyric Soprano


  • Has shown improvement in stability, nasality, support, intonation and control since debut
  • Able to keep a relaxed supported sound up until A4 and Bb4 occasionally
  • Able to support down to A3 with enough vocal tone and projection
  • Able to switch into falsetto comfortably and stay in that register
  • Has earned enough support to have a somewhat supported one octave range
  • At times notes in between B4 ~ C#5 can be done with little strain
  • Tied as second strongest vocalist in f(x)


  • Very limited vocal range and supported range
  • Notes below A3, although present, become cloudier and less clear as she descends
  • Airiness is very present in her voice, in falsetto, mix and lower range
  • Her falsetto is very weak and sounds quite limited in terms of projection and placement
  • Larynx raises quickly in her mix and isn’t stable throughout her range
  • Nasality is present in all of her voice
  • Intonation may at times go off and cause flatness in pitch
  • Tone production is very weak and shaky
  • Lacks control of dynamics and support
  • Lacks power and resonance
  • Her vibrato is a very shaky wobble
  • Notes above Bb4 are often strained, whiny, and achieved with a high larynx


  • Lower register: Very unsupported and underdeveloped, notes below A3 generally are considerably airy and weak in placement and cord connection. Able to extend down to above F#3/F3 with some vocal tone and down to C#3 overall.
  • Mixed register: Generally very weak in support and placement and although stability of larynx is kept up until A4/Bb4, true support is quite weak due to the unstable wobbly vibrato and tension. She has shown the ability to extend her mix up until E5, however.
  • Upper register: Very limited and airy, with weak support. Although she’s able to switch into it easily and keep a stable pitch, the tone production is quite shaky and small in sound. She uses this register well, though, when avoiding the strain on her voice by switching into falsetto at times.


Possessing a very light voice, Krystal lacks control and stability in her breath support resulting in a voice that isn’t capable of many advanced techniques, one of these being vocal runs/ornaments. She rarely, if ever, attempts anything outside of her comfort zone and she occasionally may play around with very simple vocal runs but they’re more trills than anything by quickly going around two to three notes in a quick word, adding more of an emphasis than any actual control of vocal agility. It shows that, since she may lack control, she doesn’t attempt to do things her voice isn’t capable of.

Overall analysis

As the lead vocalist of f(x) and the second strongest vocalist in the group, Krystal has earned a name for herself in the K-pop music industry as a singer, dancer, actress and last, but not least, the younger sister of Girls’ Generation’s Jessica. As such, she and her sister not only share similar looks, but also similar voice tones. Krystal’s voice light and bright like her sister’s, but more fragile and smaller in size and volume. A very youthful girly tone, Krystal’s voice is a light-lyric soprano with a voice that is instantly recognizable as her own, or at times mistaken as her sister’s.

As a vocalist, Krystal has always been highly overshadowed by group mate Luna, whose vocal technique, skill and power create such a gap between the two. Nonetheless, Krystal is still a lead vocalist in the group and should be treated as such. As a vocalist, Krystal still has a very underdeveloped voice in every single register, lacking true support, stability and control, although having shown improvement from debut until now, her overall skill still is very minimal.

Her lower range has been showcased and commonly highlighted for it is where Krystal’s voice sits most comfortably without as much strain, but even then it lacks control and development. Notes from A3 and above generally show a more stable and forward sound, an improvement visible in her performance with fellow label-mate EXO’s Chen, in a performance of “좋았던 건, 아팠던 건 (When I Was… When U were…)” where, at times she’d go below A3 and then the tone was lost and the overall support was weak, however above she’d have more stability and project better. In the performance of “You Are My Destiny“, a duet with Luna, she shows little to no ability to maintain stability and projection in her lower range, even as high as A3. On numerous occasions, Krystal tends to become airy, cloudy and unclear in her lower range, another example being her G3’s in “Sorry (Dear Daddy)“, in which she shows clear discomfort to sit so low in the third octave, although being able to hit notes as low as E3.

As a Soprano, it’d be understandable that Krystal’s voice would find more of a lift as she ascends into the fourth and fifth octave, but due to her weak breath support, that is not the case. Such as in performances mentioned above, Krystal tends to sound unstable and shaky on her mid-fourth octave and sound like she’s pushing her range higher with a high larynx, a thin and weak sound coming out. Examples being her B4’s in “Sorry (Dear Daddy)” and her C5, D5 and Eb5 in “You Are My Destiny“. Krystal still naturally does have a Soprano voice, so although her technique may lack, she is able to push her range up until E5 in songs such as “Pretty Girl” and the live cover re-edition of Girls’ Generation’s “Kissing You“, where she covered Jessica’s sustained E5, with a very high larynx, whiny quality in sound and flat tone. Even with their recent 2014 comeback, Krystal still shows a thin, whiny and strained quality in her mixed voice on D5’s and C#5’s, even B4’s, such as in “Red Light“. Even then, at times she shows a certain ease when she needs to sing quick notes in her mix and doesn’t let her throat close nor does she push too much chest into her mix, example being her performance of “Don’t Speak” where at times she’d jump to quick C5’s with no apparent struggle, although her larynx was never stable. She has still however shown to be able to support her voice up to Bb4 at times, such as in “거울아 거울아” and A4’s, such as in “Red Light” and “LaChaTa“.

Further up into her range, Krystal has yet to show a clear and connected transition into head voice, opting instead to use a nasal and weak airy falsetto. Most of the time, Krystal will show that she’s able to switch into this register with relative ease, without breaking her voice nor losing the speed of the song, showing that she’s got the muscle coordination in her vocal cords to properly switch and keep herself from trying to strain higher into her mixed range. Even then, the actual sound of her falsetto is still limited and has only been extended as high as F#5, in studio.

Krystal’s main attributes lie in the control she has of her voice, generally being able to stay in tune for her vocal performances and her ability to switch into falsetto and control her voice so that she keeps it in a healthier manner. She also has shown improvement in keeping stability and support around the A3 to A4 octave, so that there’s not much strain nor weakness to her voice. This allows her to properly sing and lend her singing voice to drama OSTs and f(x)’s songs, where the most challenging lines are sung by Luna.

Her biggest weakness, however, lie still in the fact that Krystal has yet to show any clear understanding of music and her voice, where most of the time she is incapable of changing dynamics and adding or taking volume from her vocal performances. Her voice generally stays the same in terms of tone production and volume, generally thin, small and shaky, lacking stability and development from bottom to top of her range. Her mix is generally just very heady, without any real concern for a balance of both chest and head voice, nor does it show any flexibility to change into a chestier or more balanced tone at will. Her vibrato also is very unhealthy and unstable, with no clear support for her vocal cords to vibrate evenly, all that comes out is a shaky wobble that takes away the stability and overall presence her voice could have. Lastly, Krystal’s voice is also very limited in placement, where she generally places it very forward but mostly in her nose, not allowing for any resonance or true projection.

Krystal is a rising star and as such, although not a skilled vocalist, shows potential to be an actress where her skills come in more handy, or a model. If she is to ever consider her life as a singer in the long run, then many things need to be worked on in order for her to transition from an idol singer and entertainer into a real vocalist and artist, where she would then allow herself to showcase the full potential of her voice.


Much like her vocal agility, due to lack of solo material it may be hard to be certain but, Krystal stays most of the time in a comfortable one octave range and doesn’t attempt to change melodies of songs she’s not comfortable singing. Instead, she shows more concern in trying to get what she already has to know for the song she’s performing right, before attempting to add anything new.


Weak to Average Vocalist

Best Vocal Performance

Vocal Range Video(s)

video by: Viettien81212

video by: 2NE1Bang

Analyzed by Ahmin (Kitsunemale)

About ahmin3

kitsunemale from YouTube, AhMin33 from Twitter and Ahmin from OneHallyu! https://www.youtube.com/user/KitsuneMale

166 thoughts on “f(x)’s Vocal Analysis: Krystal

  1. I can’t believe I’m just now reading Krystal’s analysis. Wow, three octaves!? I was not expecting that. And a whole octave of support!? Even her rating somewhat impressed me. I was so sure she’d be weak.
    Do you think she has a stronger lean to Weak or to Average? Or is she fairly even split?


      1. I was so certain that Amber would be the 2nd strongest….She just sounds more effortless and her voice sounds “smoother” than Krystal’s….


  2. Great analysis. Also who would you believe would be the stronger vocalist between CL and Krystal? reasons why and how higher is one from eachother?
    Also do you think Seola from WJSN is better than Krystal and why ? thanks in advance


    1. Seola is a weak vocalist so I don’t believe she’s better than Krystal. She has a very weak sense of support, weaker than Krystal. CL is a rapper, so I don’t pay attention to get singing enough to answer your question, I’m afraid.


    1. It isn’t about what note she supports, but instead how she supports. If Krystal had shallow support down to G3, it would still be shallow support. It’s about how the support is engaged in her instrument, she’s a lot more likely to be average by having a stronger and more consistent sense of support within the same actual range she has it now, than by extending her supported range lower.


      1. By definition a falsetto is never “good.” A falsetto can be relaxed which in itself is a good thing, but a falsetto is never good because it indicates a lack of full development of the vocal cords in order to produce a head voice. The falsetto register is not connected enough and therefore it can’t be supported. If a register isn’t supported, then it isn’t good. A head voice can be good, it can also be unsupported or even resonant. A falsetto can’t be supported nor resonant, only unsupported. It can be tense or relaxed though. So this isn’t bad, it’s in pitch but it’s a falsetto. It’s nasal, it’s airy and it lacks development for her upper register.


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