Interviewer: Hello, Composer WonWoo Lee. Thank you for taking the time to speak with me despite your busy schedule.

WonWoo Lee: Hello. My name is WonWoo Lee, and I currently work under the name WonWoo Lee. I’m a lecturer at the Korea National University of Arts, and I create music specifically for cochlear implant users.

Interviewer: Could you explain what a cochlear implant is?

WonWoo Lee: A cochlear implant is a medical device that has been in use for about 30 years, developed in countries like Australia and the United States to assist individuals with hearing impairments. Unlike hearing aids that amplify sound, cochlear implants use a SUS (Suspended or Sustained Stimulus) mechanism. Electrodes are implanted in the cochlea, and an external microphone captures sound, converting it into electrical signals that are directly transmitted to the cochlea. Typically, these implants have around 12 to 20 electrodes, each responding to a specific frequency, enabling users to distinguish between frequencies.

Interviewer: I’ve heard that cochlear implant users hear sounds quite differently from individuals with normal hearing. Is that correct?

WonWoo Lee: Yes, that’s true. The human cochlea typically contains about 3,000 hair cells, which enable us to distinguish a wide range of frequencies. Cochlear implants, however, only have 12 to 20 electrodes. This makes it much harder for implant users to distinguish frequencies with the same sensitivity as natural cochlear hair cells. In fact, research suggests that increasing the number of electrodes for more detailed frequency distinction might result in users hearing more “noise”—unnecessary sounds—which makes it even harder to perceive desired sounds clearly.

Here’s an example of what sound might be like for cochlear implant users. Take a listen.

(Sound: News audio as perceived by cochlear implant users)

Interviewer: Wow, it sounds much more mechanical than I expected. Honestly, I can barely make out what’s being said.

WonWoo Lee: Right, but with training, most people adapt to speech over time. For instance, if you listen to the original version of that audio and then compare it to the version perceived by cochlear implant users, you’ll notice it becomes easier to understand. Let’s try it.

(Sound: Original news audio / Cochlear implant user’s version)

Interviewer: Oh, I see what you mean. It’s much clearer now.

WonWoo Lee: Humans don’t process sound entirely in real time; they predict and interpret it as they listen. That’s why cochlear implant users can generally adapt to speech after about a year of use, as speech follows relatively consistent grammatical patterns. However, music is a different story. Each composer’s musical language is unique, and unlike speech, which focuses on meaning, music requires direct perception of sound itself. This presents a much greater challenge. Let’s listen to the same comparison, but this time with music.

(Sound: Processed music / Original music / Processed music again)

Interviewer: The processed version sounds entirely different from the original. It even feels like modern experimental music. But unlike speech, even after hearing the original, I still can’t quite grasp the processed version.

WonWoo Lee: Exactly. That realization made me reflect on why I had assumed everyone hears the same sounds I do. This prompted me to create music specifically designed for cochlear implant users.

Interviewer: How is music for cochlear implant users different?

WonWoo Lee: First, they have difficulty distinguishing frequencies such as “Do” and “Mi,” which might sound almost identical. To address this, melodies often involve leaps to make them more distinguishable. Rhythms tend to be simpler, and sounds with short sustain—like percussion—are easier for them to perceive. Additionally, too much reverb creates lingering noise, making it harder for users to discern sounds, so we minimize reverb as much as possible.

These compositions can serve both as enjoyable music and as tools for rehabilitation, helping users become accustomed to specific frequencies. I’m also currently working on developing an application that compiles these pieces.

Interviewer: Thank you for sharing that. Lastly, could you tell us what “sound” means to you?

WonWoo Lee: To me, sound is something unstructured within the flow of time. When it gains structure, it becomes music.

Interviewer: That’s a profound and unique definition. My current project explores the subjectivity of sound perception. Do you believe sound inherently has subjective characteristics?

WonWoo Lee: Absolutely. For instance, I personally can’t hear sounds above 15,000Hz, so whenever I mix music, my high frequencies tend to be overly pronounced. From physical processes to cognitive perception, everyone processes sound differently. Cochlear implant users are an extreme example of this variability. Sound is, without a doubt, subjective.