Introduction
It can make the best guitar player sound better, but it can also destroy speech intelligibility to the point of ruining any type of live performance. Certain spaces, namely orchestra and symphony halls, need the right amount of it… but not too much, and not too little. “It” is reverberation.
Typically, reverberation can be controlled with adding sound absorption to the space to reduce the reflection, or altered with sound diffusion to scatter and increase reflection points.
What is Reverberation?
After a sound’s source has become silent, the sound will continue to reflect off surfaces until the sound wave loses energy and fades away. This continuation of the sound is called reverberation or reverb and can be measured by reverberation time.
The reverb time of a room is the time it takes for sound to decay by 60 decibels once the source of sound has stopped. Reverb time is the basic acoustical property of a room which depends only on its dimensions and the absorptive properties of its surfaces and contents. Reverberation has an important impact on speech intelligibility and can be improved by adding additional sound absorbing acoustic panels or acoustical ceiling treatments as well.
Why is Reverberation important?
Reverberation Diagram
Reverberation is not always a bad thing. It can also be extremely useful depending on the application. It can transport an audience to a large church, amphitheater, cavern, or an intimate performance space. Similarly, reverberation can create natural or artificial harmonics of a sound source to shine through and can give the sound additional warmth and stereoscopic space. Therefore, it sounds fuller, broader, and more natural to the human ear. Without reverb, a place can sound “dead” and can be as unpleasant as a room that is too “live” with too much reverb.
Examples of Reverberation
Here are some recordings of various reverb times and a chart showing optimal reverberation times in certain types of space depending of the amount of sound absorption going on in the room.
One-second reverb time
Two-second reverb time
Three-second reverb time
Six -second reverb time
Now… what should you be aiming for? What spaces need to be at what reverberation times? Here’s a chart that may help with deciding what is the best reverb time for your space.
Reverberation Time in Seconds
Tips And Reminders For Reverberation
Sometimes, it is not necessary to lessen the reverb time by adding acoustical absorption. It may be that the space is too dead sounding and diffuser panels may be needed to scatter or disperse the sound throughout the room. Similarly, diffusion can reduce standing waves while maintaining the “live” ambience of the space.
If you’re unable to determine the reverb time in your space, you can always have our site visit service performed to evaluate that for you. After that, our acoustical sales consultants can assist you with getting the best possible treatment that’s right for your space and budget!
Summary
In conclusion, reverberation is a key factor in defining how a space will respond to an acoustic sound. Whether you are needing to lessen or alter your room’s existing reverberation time, Acoustical Solutions has the right materials and services you need to achieve your sound improvement goals
To learn more about how Acoustical Solutions can solve your noise control problems, use our contact form, call one of our Acoustical Sales Consultants at (800) 782-5742, or visit us on the web at acousticalsolutions.com.
It will help slightly, but the lion’s share of the sound that comes through walls and structures is in the low-frequency range, and lightweight acoustic foam simply does not block those frequencies very well. The reason is, those frequencies telegraph themselves through the structure. Acoustic foam works best on windows, which are more compliant to sounds in the higher frequency range than walls and two-by-fours, and in that regard, the foam will do a better job of attenuating those frequencies. When recording studios need to isolate one recording room from another, they float both of them on rubber pads or rubber bladders, in addition to adding layers of lightweight insulation interleaved with heavy layers of metal or lead to the walls and ceiling. The layers being designed to attenuate sounds traveling through the air between rooms, and the rubber footing to attenuate the low frequencies that travel through the structure. If you can convince the TV-watcher to turn off or turn down the subwoofer, or reduce the bass using the equalizer/tone controls (at least when it’s bothering you if there’s any leeway), that would be the best solution.
You made some great points there, thanks. You’re right, lower frequency noise is harder to block. 2″ thick panels or bass traps would be more effective at reducing reverberation than some foams, but as far as actually stopping the sound’s transmission through walls and ceilings, isolation would be the most effective method, combined with the addition of very dense materials like mass loaded vinyl.