Auditorium, Faculty of Engineering, Chulalongkorn University

“Echoes in the auditorium are not always solved by the walls. The real answer might be ‘above your head’.”

| Trandar Gedina E |

"Lecturers speak 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 swirls in the room, making it unintelligible." "Walls cannot be changed, the structure cannot be touched — so how can we reduce the echo?"

This was the real challenge for the Auditorium of the Faculty of Engineering, Chulalongkorn University. And this is the story of a clever, fast, and effective solution that didn't require touching the walls at all.

📖 Project Story — When a University Auditorium Had to Fight Its Own Echoes

The Auditorium of the Faculty of Engineering, Chulalongkorn University, is a central venue for numerous important activities, whether special lectures, academic seminars, ceremonies, or institutional meetings. Every time it is used, the expectation of the attendees is the same —

Clear hearing, understanding every word, from the front row to the very last.

However, in reality, the opposite occurred. The speaker's voice from the microphone, instead of traveling directly to the listeners' ears, was repeatedly reflected from all sides of the room, becoming an echoing, overlapping sound. The faster they spoke, the harder it was to understand.

🔊 Problem Analysis — Walls That Refuse to Absorb Even a Bit of Sound

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

The auditorium walls were built with hard materials, including concrete, brick, and decorative materials with no sound-absorbing properties whatsoever. Every sound wave hitting the walls was reflected 100% with no absorption occurring. And with a room having four walls all acting like sound mirrors, the room's Reverberation Time was excessively high compared to the standard for a functional auditorium.

And what made this challenge harder than typical projects was all walls could not be touched, whether due to structural reasons, architectural design, or operational restrictions within the university area.

Only one place remained — the ceiling

🛠 The Right Solution — Trandar Gedina E T-bar T15, a Perfect Pair Born to Combat Echoes

Since the only available area was the ceiling, the Trandar team designed the ceiling to work as hard as possible, opting to install Trandar Gedina E across the entire ceiling area of the auditorium, on the Trandar T-bar T15 suspension system.

✅ Trandar Gedina E — NRC 0.8 absorbs 80% of all incoming waves

Gedina E is not just a regular ceiling panel; it is an Acoustic Panel specifically designed for sound absorption. With a high NRC (Noise Reduction Coefficient) value of 0.8, it means that when sound waves hit the Gedina E panel, 80% of the sound energy is absorbed and disappears, with only 20% reflected.

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

When Gedina E was installed to cover the entire ceiling, sound waves that previously echoed in the room were trapped and absorbed by the ceiling every time they hit it, rapidly reducing the number of reflections. This brought the room's Reverberation Time down to an appropriate level for auditorium use.

✅ Trandar T-bar T15 — The suspension frame that makes everything fit perfectly

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

In large auditorium spaces, the precision of the ceiling plane is crucial, as even slight inconsistencies would affect sound reflection patterns and overall absorption efficiency. T-bar T15 perfectly solves this problem, providing an accurate plane, stable load-bearing capacity, and readiness for long-term maintenance.

After the installation of Trandar Gedina E on T-bar T15, covering the entire auditorium ceiling, the changes were clear and measurable.

The distracting echoes completely disappeared. Speakers spoke at a normal volume, and attendees in the last row heard every word clearly as if sitting in the front. Meetings and seminars that previously required repetition because listeners couldn't hear became unnecessary.

And most importantly — all of this was achieved without touching the original walls or structure at all.

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