Acoustic Design for Meeting Rooms, Offices, and Classrooms
Acoustic design is not just a concert-hall concern — meeting rooms, offices, classrooms, restaurants, and airports all rely on it too, even when nobody names it that way. This article, drawing on ALTA Integra's experience as an acoustic consultant, explains how acoustic consultants determine the right acoustic design for a room based on what its audience is actually there to listen to.
Why Beautifully Designed Rooms Still Fail Acoustically
We have all experienced it: a panelist's dialogue at a conference that is hard to follow, music at a rock concert that sounds frenetic and muddy, a restaurant so loud you can't speak quietly at your own table, or a flight announcement at an airport that's simply inaudible. These are not decoration problems — they are acoustic design problems.
They happen because acoustic consultants are often left out of the early stages of space planning. The result is a room that looks beautiful on paper but becomes functionally redundant the moment people try to actually use it for its intended purpose.
Reverberation Time (RT60): The Starting Point for Every Acoustic Design
One of the most important values to calculate early in the design of any room involving an audience is its RT60 — the reverberation time, or how long it takes sound energy in the room to decay by 60 decibels after the source stops. Getting the RT60 value right for a room's spatial allocation and intended use is the foundation everything else in acoustic design builds on. A companion article on RT60 calculation and echo-dampening materials covers the technical derivation in more depth.
Case Comparisons: Conference Room vs Concert Hall
Consider a conference room designed for a maximum audience of 800 people, where roughly 80% of the audience's main activity is listening to dialogue. That room needs an RT60 value planned specifically so listeners can hear dialogue clearly, without words piling up on top of each other due to excessive echo. A good conference room design depends on getting this one variable right.
Compare that to a concert hall seating around 2,000 people, where roughly 90% of the audience's activity is listening to acoustic music performances rather than speech. An orchestra performance typically uses no amplification at all — a violin, a soprano's voice, or a tenor's voice needs to reach the back row purely through the reflection and diffusion of sound that a well-designed room provides.
The Sydney Opera House is a well-known example of this kind of design done well: with a capacity of 2,800 people, it is regarded as one of the best-designed orchestral concert halls and theatres in the world, with a measured reverberation time (RT) and early decay time (EDT) of 2.1 seconds.
Matching Acoustic Design to What the Audience Is Listening To
The common thread across both examples is this: the room's acoustic design should be based on the audience's main listening activity and the type of sound source involved. Broadly, audiences in a room listen to some combination of: dialogue, music, a mix of music and dialogue, or a mix of music, dialogue, and noise.
Based on this, architects and acoustic engineers typically classify rooms by function:
1. Conference rooms — dialogue
2. Cinemas — dialogue, noise, and music
3. Theatres — dialogue and music
4. Pop / rock / jazz concert rooms — music with loudspeakers
5. Orchestral concert rooms — acoustic music without loudspeakers
6. Worship rooms — dialogue and music
7. Restaurants — dialogue and background music
8. Night clubs — music at relatively high sound pressure levels
Industry practice pairs each of these room types with a recommended RT60 range:
| Room type | Recommended RT60 (seconds) |
|---|---|
| Conference hall | 0.6 – 1.3 |
| Cinema | 0.6 – 1.2 |
| Theatre | 1.0 – 1.8 |
| Pop / rock concert room | 1.4 – 2.0 |
| Orchestral concert room | 1.6 – 3.0 |
| Worship room | 1.8 – 3.2 |
| Restaurant | up to 1.8 |
| Night club | 0.6 – 1.6 |
Putting It Together: Acoustic Panels and Interior Design
RT60 targeting alone is not the whole job. Once the right range is set for a room's function, that target has to be achieved through the correct combination of acoustic panels, absorptive and reflective surface planning, and interior design choices — ideally worked out alongside the interior designer and architect rather than bolted on afterward. This is the kind of coordinated acoustic design work ALTA Integra carries out for meeting rooms, offices, classrooms, and performance spaces alike. Done this way, a room can be beautiful and functional at the same time, maximizing the experience for whoever is sitting in the audience.
Frequently Asked Questions
What is RT60 in acoustic design?
RT60 (reverberation time) is the time it takes for sound energy in a room to decay by 60 decibels after the sound source stops. It is one of the first values calculated when designing any room's acoustics.
Do offices and classrooms really need acoustic design, not just concert halls?
Yes. Any room where people need to hear dialogue clearly — offices, classrooms, meeting rooms, worship spaces, restaurants — has its own recommended RT60 range and benefits from acoustic design just as much as a concert hall does.
What RT60 range is recommended for a conference room?
Roughly 0.6 to 1.3 seconds, since the main activity in a conference room is listening to dialogue, which needs clarity rather than a long, music-friendly decay.
Why does an orchestral concert hall need a much longer RT60 than a conference room?
Acoustic music without amplification relies on the room's own reflections and diffusion to carry and blend sound to the audience, so orchestral halls are designed with a longer reverberation time (typically 1.6–3.0 seconds) than speech-focused rooms.
When should an acoustic consultant be brought into a project?
As early as possible — ideally during initial space planning, before layout and finishes are finalized, so the RT60 target and material choices can shape the design rather than compensate for it afterward.
Suggested internal links: Acoustic Engineering Design, Reverberation and Echo, Noise Criteria: A Background Noise Rating Standard.
