In this blog post, we’ll explore how the structure and acoustic characteristics of a concert hall influence the way music is conveyed.
While studying in the Department of Materials Science and Engineering at Seoul National University’s College of Engineering, I was a member of the Seoul National University Choir starting in my freshman year. During my three years in the choir, I performed on stages of all sizes and practiced in a variety of venues. However, through these experiences, I realized that even when singing the same song, the listening experience varies greatly depending on where we perform.
In particular, this difference was even more pronounced when singing in a concert hall versus a non-concert hall space. Based on my experience, to give a specific example: there was a marked difference in the sound of our singing between our weekly regular rehearsals in the large rehearsal room of the Student Union Building and our choral performances in the Grand Auditorium of the University Cultural Center. When rehearsing in the large rehearsal room of the Student Union Building, the sound was very loud and clear, and the acoustics allowed the voices to resonate well, creating a sense of natural harmony with the other sections. However, when performing on a stage like the Cultural Center’s Grand Auditorium, unlike during practice in the large rehearsal room, I could barely hear the voices of other sections—or even those of my own section standing right next to me. It was a unique experience: even though I was singing with many others, I could hear only my own voice. I also recall that when I first performed at the Cultural Center’s Grand Auditorium, it felt as though I wasn’t singing as well as I usually did during practice.
This experience raised a question for me. Even though performance venues like the Culture Center’s Grand Auditorium are designed specifically for classical music performances, including choral music, why does it feel as though one’s singing isn’t as good as when singing in a practice room? To address this question, I will compare the two spaces—the large practice room in the Student Union Building and the Culture Center’s Grand Auditorium—and examine how each space transmits sound. I will also explore the characteristics of spaces—such as the Culture Hall Auditorium—that are specifically designed to present performances to an audience.
Before comparing how sound reaches our ears in the large practice room and the Culture Hall Auditorium, it is necessary to first examine the process through which sound reaches our ears. You may recall experiments from elementary school science class where you struck a drum and then touched its surface, or struck a tuning fork and touched it immediately afterward. When you strike a drum or a tuning fork, you can feel the object vibrating through your fingertips. In this way, sound is generated by the vibration of an object, and the sound produced in this manner is transmitted to our ears in the form of sound waves through the surrounding medium—air. Therefore, we can see that the surrounding medium and the spatial environment play a very important role in the process of sound transmission.
Good sound transmission is a crucial factor in concert halls, because it is not just sound but music that is conveyed to the audience. So, what conditions must a venue for classical music performances—such as choral concerts—meet? A good concert hall is designed with appropriate sound-absorbing features, utilizing reflectors above the stage and reflective structures on the sides of the audience seating area to ensure that the music is delivered evenly throughout the entire auditorium. In other words, a good concert hall is not simply a space where sound resonates loudly, but rather a space where a large audience can hear the music with consistent sound quality while maintaining appropriate volume and clarity.
So, what about large rehearsal rooms and the main auditoriums of cultural centers? The walls of large rehearsal rooms are made of materials similar to those found in ordinary buildings. When sound hits these walls, most of it is reflected back exactly as it was. For example, if the sound is traveling upward, the sound that hits the ceiling scatters in various directions and returns toward the performer. When sound that has spread in all directions is reflected chaotically off the walls in this way, it creates significant reverberation throughout the entire space.
However, this diffuse reflection interferes with the original sound of the song that should be transmitted, ultimately hindering the performer’s ability to accurately convey the intended music. In contrast, performance venues such as the main auditorium of a cultural center appropriately apply sound-absorbing materials and reflective structures to walls and ceilings to reduce unnecessary reflections and control necessary reflections. As a result, sound is transmitted more clearly to the audience without excessive overlap.
Just as the materials used for the walls of a performance venue significantly influence sound transmission, the venue’s three-dimensional internal structure also plays a crucial role in how music is conveyed. Performance venues are designed with reverberation time in mind to provide uniform acoustics to a large audience. In a given space, direct sound reaches the ears first, and then sound reflected off the walls and ceiling is added, resulting in a steady overall sound level. The sound that lingers for a certain period after the original sound has ceased is called reverberation, and the time it takes for the reverberation to decrease to a certain level is called the reverberation time. The reason reverberation time is crucial in concert hall design is that an appropriate level of reverberation is necessary for music to sound rich yet clear. Today’s concert halls are designed to ensure an appropriate reverberation time based on the purpose of the performance, and the reflective structures of the ceiling and walls ensure that sound is naturally distributed throughout the entire audience area. In contrast, in spaces with simple cubic structures, such as large rehearsal rooms, reflected sound is generated randomly, creating significant reverberation; however, it is difficult to achieve the uniform and refined acoustics found in performance halls.
Consequently, when rehearsing a choir in a large rehearsal room, the sound of singing bounces off the walls and reflects in multiple directions, making it easy to perceive a loud and rich reverberation. In contrast, in the Cultural Center’s Grand Auditorium, the acoustic design ensures that sound is efficiently directed toward the audience; consequently, performers hear their own voices more clearly, and the overall resonance of the choir may feel less pronounced than in a practice room. Therefore, from a performer’s perspective, practicing in a large practice room may feel like the singing sounds better than when performing in the Cultural Center’s Grand Auditorium. However, in reality, a structure like that of a performance hall is better suited to delivering music to the audience in a much more natural and balanced way. Thanks to the acoustic design of such venues, the audience can appreciate the music the performers intend to convey in a more beautiful and rich manner.
When presenting music to an audience, how the music is delivered is just as important as the quality of the performance itself. This is because even the same piece of music can sound vastly different to the audience depending on the space in which it is performed. Thus, even concert halls that appear merely grand and beautiful are built on scientific principles designed to allow the audience to experience music in a richer and more natural way. A variety of instruments are played in concert halls. But might we not say that the concert hall itself—which conveys the sounds created by the performers to the audience in their most beautiful form—is another massive “instrument”?
