Faculty of Engineering Auditorium, Chulalongkorn University

“Echoes in the auditorium aren't always solved at the walls. The real answer might be ‘above your head’.”

| Trandar Series E |

"Presenting at the front, but people in the back rows only hear echoes." "No matter how loud the mic is, it doesn't help because the sound bounces around the room until it's unintelligible." "We can't change the walls, we can't touch the structure — so how do we reduce the echo?"

This is the real challenge of the Auditorium at the Faculty of Engineering, Chulalongkorn University, and this is the story of a smart, fast, and truly effective solution without touching a single wall.

📖 Project Story — When a university-level auditorium battles its own echoes

Auditorium of the Faculty of Engineering, Chulalongkorn University is the central hub for numerous important activities, whether special lectures, academic seminars, official ceremonies, or institutional meetings. Every time it is used, the audience's expectation is the same — to hear clearly and understand every word, from the front row to the very back.

In reality, however, the opposite happened. The speaker's voice from the microphone, instead of traveling directly to the listeners' ears, was repeatedly reflected off every wall in the room, creating overlapping echoes that circulated endlessly. The faster the speaker talked, the harder it was to understand.

🔊 Problem Analysis — The walls that refused to absorb any sound at all

When the Trandar Acoustics team surveyed the area, the cause of the problem immediately became clear.

The auditorium walls were built with hard materials—concrete, brick, and decorative finishes with zero sound-absorption properties. Every sound wave hitting the walls was 100% reflected with no absorption taking place. With four walls acting essentially as acoustic mirrors, the room's Reverberation Time was far higher than the standard for a functional auditorium.

What made this challenge harder than typical projects was that none of the walls could be touched, whether due to structural, architectural reasons, or operational restrictions within the university premises.

There was only one place left — the ceiling.

🛠 The Right Solution — Trandar Series E + T-bar T15, the dynamic duo built to stop echoes

Since the only available surface was the ceiling, the Trandar team designed the ceiling to work as hard as possible, opting for Trandar Series E installed across the entire auditorium ceiling on a Trandar T-bar T15 suspension grid.

✅ Trandar Series E — NRC 0.8, absorbing 80% of all impacting waves

Series E is not just an ordinary ceiling tile, but an Acoustic Panel specifically designed for sound absorption. With an NRC (Noise Reduction Coefficient) as high as 0.8, it means when sound waves hit the Series E panels, 80% of the sound energy is absorbed and dissipated, leaving only 20% reflected.

Compared to the original concrete walls that reflected nearly 100% of the sound, the difference is massive.

By installing Series E across the entire ceiling, sound waves that previously echoed around the room are captured and absorbed at the ceiling every time they make contact, rapidly reducing the number of reflections and bringing the room's Reverberation Time down to an optimal level for auditorium use.

✅ Trandar T-bar T15 — The suspension grid that brings everything together perfectly

T-bar T15 is a ceiling suspension system designed to securely support acoustic panels and maintain a uniform level across large areas.

In a wide auditorium space, ceiling flatness and precision are critical because even minor irregularities affect sound reflection direction and overall absorption efficiency. T-bar T15 solves this perfectly, providing precise leveling, robust weight capacity, and readiness for long-term maintenance.

Following the installation of Trandar Series E on T15 T-bars across the entire auditorium ceiling, the transformation was clear and measurable.

The echo that once caused disturbance completely disappeared. Speakers could talk at a normal volume, and audience members in the back row could hear every word just as clearly as those in the front. Meetings and seminars, which previously required repeating information because the audience couldn't hear, were no longer an issue.

Most importantly — all of this was achieved without touching a single wall or existing structure.

"A good engineer doesn't solve problems by demolishing and rebuilding — but by finding the right spot and making it the best."