Why It’s Important to Have Proper Acoustics in a Lecture Hall
June 24, 2020
Lecture halls are found on almost every college campus. These rooms are multi-functional and are often used as classrooms. They can also be used for events where there are guest speakers and presentations.
Though lecture hall use may vary, speech intelligibility remains the one constant no matter the event. For instructors to successfully communicate with students, there must be good speech intelligibility and low background noise. To achieve this type of listening environment, you need to consider the proper acoustical sound treatment.
As manufacturers of lecture hall seating, auditorium seating and a supplier of acoustic solutions, we understand the importance of good acoustics for your space. In this article we will discuss why it is crucial to have proper acoustics in a lecture hall, the problems that surface when there are no acoustics and how good acoustical treatment can help.
Why It’s Important to Have Proper Acoustics in a Lecture Hall:
Lecture halls and auditoriums tend to be large, impersonal rooms with long walls often made of highly reflective materials such as concrete block, gypsum board and tile; all of which are perfect incubators for long trailing echoes. Acoustically, the goal is to allow audience members to easily hear and understand the presenter. To accomplish this goal, you need to properly balance sound absorption and sound reflection.
To provide a favorable acoustical environment you must address both the need to hear and understand speech, and the desire to have a pleasant space for music. The recommended reverberation time for the typical lecture hall is 1-1.5 seconds. This means that the sound will have completely dissipated after 1-1.5 seconds. For acoustical purposes, you can divide a lecture hall into thirds. The front third including the stage or front of the room, can be reflective enabling sound to reach the audience. The middle third of the room can be a combination of absorptive and reflective and the back third of the room should be absorptive materials to help reduce the reverberation time and unwanted reflections back into the room.
Parallel reflective surfaces can allow sound to "ricochet" back and forth between the surfaces. This potentially annoying condition is referred to as standing wave or flutter echo. It can be avoided by designing non-parallel surfaces or by adding absorptive materials to the surface(s).
The Problem with Lecture Halls Not Having Proper Acoustic Treatment:
When there are no acoustics present, lecture halls can be very noisy. The professor’s spoken lesson, or sound from the audio-visual system, bounces off the hard surfaces creating powerful first order reflections and is followed by secondary echoes that together create a jumble of noise that is difficult to understand. This causes the student’s brain to work extra hard to discern between the important message he or she wants to hear and the unwanted ambiance that gets in the way. Intelligibility is impeded and the student’s learning experience is compromised.
The problem is more noticeable in larger rooms, as the echo arrives well after the desired message further disrupting communication. To address the problem, a PA system is often introduced which can make matters even worse as the room’s reverberation levels increase, the students lose interest and the presentation is lost on the attendees.
How Proper Acoustic Treatment Can Help and the Different Options to Choose From:
You can eliminate the primary and secondary reflections by covering between 15-25% of the wall surface area with 2” thick acoustic panels. Acoustical wall and ceiling panels are designed to solve your acoustical needs while enhancing the aesthetic of your space.
There are a variety of options to choose from, including various sizes, shapes, fabrics and colors, making it easy to create the perfect solution for your reverberation sound problems. In addition to fabric wrapped panels, you have options for printed graphic panels and paintable fabric panels to match a room’s aesthetics.
Benefits of Good Acoustic Treatment:
The effectiveness of acoustic treatment is generally in proportion to the square footage used. If several hundred square feet of acoustic treatment is used in an average sized lecture hall, it is unlikely that significant reverberation will build up in the space.
When the proper acoustics are in place, you can enjoy the following benefits:
- Improved speech intelligibility by minimizing disruptive reverb / echo
- Improved individual comfort levels
- Better learning environments
- Added aesthetics or designs
Remember, good room acoustics are not a luxury but a necessity!
Sedia Systems is the leading global manufacturer of lecture hall and auditorium furniture. We offer the widest range of fixed seating for the education, corporate, healthcare, government, public assembly markets and provide acoustic solutions for each of these markets. If you are looking for a supplier for your next acoustics project and have any questions regarding an auditorium or lecture hall solution, contact us directly or leave a comment below.