School is out for summer, and we want to take advantage of the time to work on the acoustics in our gymnasium, classrooms, and cafeteria. What would you recommend?
You’re in good company! Teachers and administrators researching acoustical treatment for classrooms, cafeterias, common areas, etc. often contact us for help, and summer and winter breaks are usually the best times to make improvements. Large common areas like cafeterias and gyms have different acoustical needs than most classrooms due to their size, and they must be approached differently. However, there are some common factors and things to consider that can be applied across the board.
In order to find the right acoustical solution for your particular situation, a bit of planning and preparation is required to learn the advantages and disadvantages of different acoustical products and methods of installation. Some of these products are custom made and will require a 1-4 week lead-time, so you’ll want to make sure to allocate enough time for that. It’s always good to request product samples so that you can see and feel the differences between products to make the best choice for your situation.
Taking the Edge Off
In the interest of simplicity, I’m going to discuss the basics of “taking the edge” off of a large space, such as a gym or cafeteria. The goal here is to reduce the reverberation time (echo) in the room so that it is simply easier and more comfortable to occupy.
I developed the following equation about seven years ago and have been using it ever since, with positive feedback from hundreds of customers. The idea here is not to try to achieve perfection, but rather to give you an idea of how to approach a room that needs acoustical treatment without having to hire an acoustical consultant.
Assuming your room has hard (usually tile) floors, drywall or cinderblock walls and either a sheetrock or metal deck ceiling:
.04 × (cubic volume of space) = approximate number of square feet of panels to put into your room.
This is probably a lot simpler than you thought it was going to be. Awesome.
The next two questions are always: “Well, where do I need to put the panels?”, and “What type of panels are you talking about?”
Where Do I Put The Panels?
The first question is easy to answer. The nice thing about acoustics is that in most elevations, sound travels in the ballpark of 1,116.43701 feet per second, which means that the sound in a room travels too quickly for the exact location of the panels to make any audible difference on the overall echo reduction. In almost all instances where one is just looking to reduce the echo, there is not going to be any overall performance differences between a wall or a ceiling mounted panel. Most of the time, in a gymnasium, it is best to put the panels directly onto the ceiling or high on the walls so that they are not hit as often with volleyballs, basketballs, etc.
What Type of Panels?
Now, when it comes to what type of panels, there are three panel types that are probably the most common for schools to install:
- Echo Eliminator recycled cotton panels
- Fabric-wrapped-fiberglass panels
- PVC or Sailcloth hanging baffle
The Echo Eliminator panels are going to be the most cost-effective option; they are generally in stock in 2′ × 4′ panels and are available in ten different colors. They are easy to ship and install, but are also generally found to be less aesthetically pleasing than the other two options.
Fabric Wrapped Panels
The fabric wrapped fiberglass panels are very decorative and finished looking, can be made in any panel size needed up to a 4′ × 10′ board and come in hundreds of different colors and fabrics. We can also print custom graphics on the fabric before wrapping for a premium price. They are, however, heavier, and can be more difficult to install.
PVC and Sailcloth Baffle
The PVC and Sailcloth baffles are hung from the ceiling like a flag. They are also custom made with plenty of choices for both baffle size and color – so school colors (or something similar) can be chosen. The downside to baffles is that they cannot usually be used in rooms that have fire-suppression sprinklers. When they are installed in the ceiling, they will commonly inhibit the throw and coverage of the sprinklers, which can violate the fire code for the building. Check with your local fire marshal before getting too far down the design path for a baffle installation.
As always, I’m happy to do what I can to help you make the best choices for both the type of panel as well as quantity. Feel free to contact me with the dimensions of your room and a few digital pictures, which are great aids for me to help you. Also, please feel free to include your personal or school address so that I am able to send you a few different product samples for your review. Finally, some schools have rooms that need to meet specific ANSI standards, and for these you can contact me directly and we can discuss your particular room further.