You are probably more concerned about acoustics if your school, performing arts center or museum has an auditorium. Acoustics in an auditorium are very important.
Although you may be aware of the importance and benefits of acoustics in auditoriums, it doesn’t necessarily mean that you are able to use them. Although auditorium acoustics can seem complicated, we can simplify them into seven key factors that affect the sound quality in this space.
ACOUSTICS IN AN Auditorium: THE IMPORTANCE
A auditorium is a gathering place that can be used for anything, from routine announcements to special performances. All these occasions share one thing in common: you want students and attendees to be able to understand what is being said. It’s not okay for a student to be unclear about the important lecture on bullying, or to sing too loudly.
Other aspects of your auditorium can be overlooked, such as the quality of seats, lighting and decor. You should not neglect the most important aspect of your auditorium, the sound. Acoustics should always be at the forefront of your auditorium design, whether you are building or renovating one. Even if your project isn’t a major renovation, there are still ways to improve the acoustics of your auditorium.
These are the goals of an effective auditorium design:
- All music, speech, and vocal performance should sound clear instead of distorted or echoy.
- The auditorium should have enough volume for everyone to hear the sound, even those seated at the back.
- It is important to isolate the right sounds, so speeches and performances can ring louder than other sounds in the room.
There are many factors that can affect the acoustics of your auditorium, as we will see. Although acoustics can seem complicated, if you have the right design you will be able to deliver better lectures and performances for students and their guests. It is worth investing in improving the acoustics of your auditorium.
FACTORS THAT AFFECT AUDITORIUM COUSTICS
The acoustics in an auditorium are affected by many factors. These factors create an auditorium with a unique acoustic environment. These factors can be used to help you design and build your auditorium. Or, you can use them to address existing problems and apply acoustic treatment to correct them.
1. The Auditorium is large
The size of a room has a significant impact on its acoustics. The room’s size is the measurement of its length, width, and height. Acoustical benefits can be found in larger auditoriums and smaller ones.
A small space won’t permit music to sound as richly in a small space, for example. A smaller room will allow you to get the entire audience to hear your music clearly, while larger auditoriums can present some difficulties. To ensure good acoustics, you also need to consider the sound system.
Reverberation is another concern due to auditorium size. We’ll talk more about it below. A larger room can result in a longer reverberation time, which can be excessive. A smaller room can result in a shorter reverberation time, which may make the room seem “dead” acoustically.
2. The Shape of the Room
The shape of your auditorium, like its size, will also play an important part in determining the acoustics. It is possible to create a computer program that reconstructs a room’s geometry using only one sound emission. Although auditoriums can be of many shapes, you will not see certain shapes as often due to poor acoustics.
Avoid square or rectangular rooms. The parallel walls can cause sound waves back and forth, causing undesirable reverberations which can muddy the overall sound quality. Many auditoriums are fan-shaped. Curved walls are also common in auditoriums, which diffuse sound. Other architectural features, such as the pitch of the ceiling or structures within the room, can also affect how sound waves behave in a space.
Many architects are skilled in designing spaces that have the right shape to provide the best acoustics for lectures and performances. You may not be allowed to modify an auditorium that is already constructed. However, there are other ways to improve the acoustics.
3. Materials in the room
Reverberation is a common problem in auditoriums. This occurs when sound waves bounce off of surfaces and congregate. Excessive reverberation is a problem that can be experienced by anyone who has ever heard a speaker speak and had difficulty understanding their message. A certain amount of reverberation can be a good thing, especially for musical performances. Otherwise, the room will feel dead.
The ideal reverberation period — the time it takes for a sound to decay — is 1.5 to 2.5 seconds in a general-purpose auditorium.
The reverberation times of most auditoriums will not be sufficient if there are no sound-absorbing materials in the room. These materials include acoustic panels and upholstered chairs. These materials can reflect sound waves and increase reverberation if they are non-porous and hard like wood floors or windows.
4. Balconies and orchestra pits
The acoustics of an auditorium that has an orchestra pit or balconies can be affected. Balconies are a great way to add more seating to a room, without making it too long. The room’s sound wave behavior is affected by the shape and materials of the balcony.
The structure and acoustics in an auditorium can also be affected by the orchestra pit. Conductors can control the level of sound coming from an orchestra pit by installing soundproof curtains.
You should also consider the acoustics inside an orchestra pit. The acoustics of an orchestra pit should be conducive to musicians being able to hear each other and their music clearly. Surveys about opera halls revealed that most people had concerns with orchestra pits. It is therefore important to plan orchestra pits strategically to ensure the best acoustics.
5. Auditorium Use
Many auditoriums are used for many purposes, particularly in universities and schools. Acoustically, this presents a problem because the ideal acoustics to hear speech is not the same as those for music. Because speech has a shorter reverberation period than music, this is important. It is possible to distinguish speech from music. The ideal acoustics to perform a cappella music is not the same as those for rock music.
Your auditorium’s acoustics may be a problem because you use it for speeches, but the same auditorium could be great for a musical. Acoustic design is a complex subject. This is why acoustics professionals approach each space as an individual project with its own challenges.
You should consider whether your auditorium will be used for a specific type of performance or event. An acoustic engineer can help create spaces that offer good acoustics for many uses.
6. Doors and buffer zones
You should also consider how spaces outside the auditorium can impact the acoustics inside. It is possible for students and audience to hear noises from outside, such as conversations, footsteps, or other sounds.
Doors can allow outside noises in. Hollow-core doors that have lower sound transmission control (STC), will block outside noises better than solid-core doors.
To prevent noise from entering auditoriums, some auditoriums have buffer zones. These areas are located between your auditorium, other rooms, such as classrooms and restrooms, or dressing rooms. These areas can be in the form of foyers or hallways and provide a buffer of space around your auditorium, that should be free from noise and activity during performances.
7. Background noises
Even though soundproof doors and buffer zones are installed to block outside noise, it doesn’t guarantee that the auditorium is silent when empty. Every room has constant noises from HVAC equipment, plumbing pipes and other background noises. These noises are usually referred to as white noise and it is not a problem in most cases. If they are not too loud, these background noises might not cause any problems in an auditorium. If the air conditioner is turned on and is loud, it can interfere with the performance and make it difficult to understand speakers.
These problems can be solved with some simple solutions. Duct liners or mufflers can absorb sound from your HVAC system and prevent it from leaking into your auditorium. There are also quieter HVAC systems. You don’t need to compromise comfort or sound quality with the right design.