“The word F*ck was said with a different voice”… Zero Base One Kim Ji-woong, obtained voice analysis report

 “Thank you~ F*ck”

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“Thank you” and “F*ck”. They’re contrasting words. Did one person say this? Fans are still divided. Some heard it as ‘F*ck’, while others speculated ‘(9) half past nine’.
(NB: F*ck in Korean is 씨발/Ssi-bal and half past nine is 아홉시반/A-hob-si-ban)

‘Zero Base One’ Kim Ji-woong has been engulfed in swearing allegations. It’s said that he cursed during a video call with fans. He emphasized that it’s not true. There are those who heard the swearing, but no one knows who said it.

Wake One’s side stated, “We will go through confirmation procedures such as digital media forensic analysis. We will clearly determine the truth.” However, the controversy didn’t die down.

Fan K, who uploaded the video, appealed, “Even with clear video evidence, are you issuing an official statement denying it only verbally? It’s unfair and distressing.” The battle over the truth continued.

What’s needed now is an objective analysis. ‘Dispatch’ obtained a voice analysis report on Kim Ji-woong conducted by the Korea Institute of Science and Technology Evaluation. It’s been summarized based on expert opinions.

(The expert is Lee XX, Ph.D. He has conducted evaluations for about 30 years at the National Institute of Scientific Investigation. He currently runs a private evaluation company.)

#What was said? (Pronunciation Analysis)

The event involves randomly selecting 30 album buyers of ‘Zero Base One’ for a video call. It took place at the ‘Wake One’ office on the 27th of last month. Each member talked for about 1 minute and 30 seconds with one fan.

There are two pieces of evidence. Firstly, a video K shared on social media. It’s 95.6MB, 3 seconds long. The segment was divided into three parts: A (F1~F5), B (F6~F8), and C (F9~F12).

Secondly, CCTV footage recorded during the event. It compares Kim Ji-woong’s mouth movements in the CCTV footage with the voice in the fan’s video.

Pronunciation was analyzed using formants. Formants refer to resonant frequencies occurring in the vocal tract. It’s a method of analyzing vocal tract imprints by examining sound frequencies. 

The results of the vocal tract analysis are as follows: A segment was identified as “Thank you,” B segment as “voiceless consonant + F*ck,” and C segment as “seems strange or seems suspicious”.

#Who said it? (Speaker Analysis)

So, who said it? K presumed it was Kim Ji-woong. If we judge based on the video, the A segment indeed matches Kim Ji-woong. However, the issue lies with the B segment, which was obscured by the screen (presumably by covering the phone or by a staff member’s hand).

The expert analyzed the speaker based on the frequency (pitch) of each segment. They examined the vocal tract’s range from low to high frequencies, dividing it into different areas.

First, the A segment. The doctor concluded, “It is presumed to be the voice of the same person recorded in the situation. (Kim Ji-woong’s) mouth movement and the formant voice production of segment A coincide,” determining Kim Ji-woong as the speaker.

The crux lies with the B segment. It should be observed between the low-frequency range (1957 Hz) and ε and α, higher frequencies. It appears to be a similar vocal tract area. In other words, it signifies the voice of one person.

However, it cannot be definitively concluded that it’s Kim Ji-woong’s voice. The expert stated, “It’s impossible to confirm the person (Kim Ji-woong) speaking in the fan video,” and remarked, “It’s difficult to determine the speaker of the B segment voice,” which also applies to the C segment.

#Is it Kim Ji-woong? (Tampering Analysis)

What if we look at the segments together? The waveform of the A-B connection was examined. There were no distortions in pitch and height in the A-B ‘connected part’. This indicates a continuous recording situation.

However, different values appeared in the ‘frequency response waveform’. At this point, the pitch and height were different. The expert concluded, “The voice of segments A-B appears to be different speakers with different voices.”

The B-C segment was also recorded continuously. However, once again, the frequency response waveform was different. The pitch and height did not match.

The analyst viewed segments A-B and B-C as ‘different speakers, different voices’. They stated, “The pronunciation of segments A and C appears to be digitally altered to the original voice through ‘pitch processing’.” 

“The pronunciation of segment B is relatively clear and distinct from segments A and C. Through vocal tract analysis, it is determined that segment B was intentionally recorded without pitch processing to maximize the focus on ‘F*ck ‘ for the listeners.”

The expert analyzed, “Judging from the shake in the fan video and the movement of the filmed subject (person, phone, etc.), it appears to have been filmed with another device,” and stated, “Segment B was recorded by an externally inserted voice.”

#The Situation of That Day (On-site Staff Interview)

The CCTV footage, which captured both the fan video and the events of the day, was compared side by side on the same timeline. However, discerning Kim Ji-woong’s mouth movements was difficult as they were obscured by the head of the member next to him.

‘Dispatch’ also interviewed staff member Mr. D who was present at the scene. Each artist was assigned one staff member for the event. Mr. D was in charge of Kim Ji-woong. He is an employee of a record company.

Kim Ji-woong was seated as the fourth person from the right out of nine. Mr. D was seated right in front of Kim Ji-woong. Both of them were simultaneously connected to earphones, listening to the conversation in real-time together. (This was a precautionary measure in case of any unforeseen circumstances, such as the need for interpretation staff.)

He stated, “I don’t remember the exact content of the conversation with K,” but emphasized, “However, I can definitely say that Kim Ji-woong did not swear. I didn’t hear anything.”

In particular, the members were seated close to each other. When one member finished the call, they would pass the phone to the next member. Even after Kim Ji-woong’s call ended, the member next to him continued their call.

He mentioned, “Another artist was continuously video-calling right next to us,” and said, “It wasn’t a situation where swearing could occur. There was no opportunity for it, and I didn’t hear anything.”


① The identified voices are A (Thank you), B (Voiceless consonant + F*ck), C (Seems strange or seems suspicious).

② In the fan video, the pitch of the A segment was manipulated during production to emphasize the pronunciation of ‘F*ck’. It is judged that the pitch was also manipulated in the C segment.

③ The pitch and height discerned in the frequency response waveforms of the A-B and B-C segments were different. Therefore, it indicates different speakers and voices.

④ The A-B-C segments were recorded consecutively. Considering the filming conditions of the fan video, there is a possibility that ‘F*ck’ was recorded externally.

⑤ Upon reviewing the CCTV footage, no peculiarities were observed in Kim Ji-woong’s mouth movements. The fan video cannot exclude the possibility of mixed surrounding voices. Therefore, it cannot be determined whether ‘F*ck’ was spoken by Kim Ji-woong.


-Originally,  they could have honestly apologized, clarified any misunderstandings, and cleanly ended it. With that attitude, fans wouldn’t keep causing trouble in the future. Why do they keep stumbling?

-Yeah, there will never be an apology, no member withdrawal or hiatus. Only the fans are really suffering, seriously.

-If they had just apologized at first, it would have been forgotten. Now it’s making me remember it againㅋㅋㅋ

-F*** really… why does this happen every time the lights go out? Wake One, I can’t enjoy fangirling because of stress… Did they apologize to the person involved…?

-The fans are the ones suffering the most. The management company is really mishandling things…

-They probably expect us to believe this, right…?

-Regardless of who did it, swearing definitely occurred, and the fans heard it, so shouldn’t an apology come first??

-Is it possible that there’s a staff member swearing right next to the artist?

-So, they’re saying it’s true that someone swore? But there are only members and staff there, right??

-Then was it a ghost??;; Is it that hard to just apologize?

-Just apologize and cover it up, the company really can’t handle its job, what are they going to do if the fans raise their voices in protest?