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Difference Between Reverb and Echo

Echo vs. Reverb: What's the Difference?

Echo vs. Reverb: What's the Difference?

For anyone who isn’t an acoustics professional, echo and reverberation can seem like they are the same thing. We all learned about echoes as kids, probably from either a book or on TV when we see a highly dramatic echo in a big cave. If you didn’t laugh at Jim Carrey’s echo in How the Grinch Stole Christmas, you just aren’t going to find us acoustics types very funny.

Reverberation entered your life at a much later age. Likely in the form of some vocabulary test or a music class. Not as fun, and not in the context of room acoustics. Reverberation buildup leads to poor acoustics in smaller spaces, like your home office or home studio. They can interrupt your conference calls or turn good music into garbled noise.

What can you do to eliminate echo and reverb? It starts with understanding the differences between them, so that you know which problem you’re trying to solve. Let’s get to it.

For anyone who isn’t an acoustics professional, echo and reverberation can seem like they are the same thing. We all learned about echoes as kids, probably from either a book or on TV when we see a highly dramatic echo in a big cave. If you didn’t laugh at Jim Carrey’s echo in How the Grinch Stole Christmas, you just aren’t going to find us acoustics types very funny.

Reverberation entered your life at a much later age. Likely in the form of some vocabulary test or a music class. Not as fun, and not in the context of room acoustics. Reverberation buildup leads to poor acoustics in smaller spaces, like your home office or home studio. They can interrupt your conference calls or turn good music into garbled noise.

What can you do to eliminate echo and reverb? It starts with understanding the differences between them, so that you know which problem you’re trying to solve. Let’s get to it.

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Popular Products to Treat Echoes and Reverberations


PolyZorbe™ Polyester Acoustic Panel
EcoVerb™ Cotton Fiber Acoustic Panel
BlocknZorbe™ Multi-Purpose Sound Panel

Echo vs. Reverb

To eliminate echo or reverb in your home or a commercial space, it’s helpful to understand the differences. The solutions can be similar, so some of you may be thinking “I don’t care! Just fix my space already!” If that’s you, we hear you. Get out your phone and call our main number or scroll right past all this and submit your room information to us. We’ll get you on the fast track.

ECHO

An echo is the distinct repetition of the original sound. It must be loud enough to be clearly heard above the general background noise in a space. You’ll hear them in large rooms like gymnasiums, cafeterias, and high-ceiling conference rooms. Echoes mostly exist in large spaces because it takes time for the sound waves to reflect off a hard surface and travel back to the listener, but it’s possible for to hear echoes (like a “flutter echo”) in small spaces with parallel walls.

REverb

Reverberations mostly occur in small spaces when the original sound is quickly reflected by multiple surfaces. You hear the reflected sounds so quickly that they pile on top of each other, resulting in garbled noise. Have you ever sung in the shower? You likely heard a weird, off-key version of your own voice thanks to reverberation. Reverb can be present in larger spaces, like an open office or in restaurant noise and gym noise. Without proper acoustical treatments, the large number of people talking results in substantial noise buildup.

acoustic panels reduce reverb in a room

How to Reduce Echo

The first step in deciding how to reduce echo in a room is whether or not people are annoyed. What makes them the most annoying? The good news is studies have been done, so we have some data to go off of. Based on the sound level of the echo above or below the direct sound level (in dB) and the time delay, we know whether greater than 50% of listeners will be annoyed. The chart looks like this:

When a sound is reflected nearly as loud as it originated, as clearly as it began, it’s hard to hear anything else. The time delay is the real kicker though. The longer it takes for the echo to be reflected (length of time is relative to distance from reflective surface), the more irritating it is. Think about it: how annoying is it when you’re on a Zoom call and you keep accidentally talking over another person because of the time delay? The principle is the same here.

Reducing echoes in a space is often complicated and requires specialized expertise. For learning’s sake, we’ve included a couple of common solutions, but you’ll need to talk to an acoustics expert (Yoohoo! We’re here!) for customized advice.

1. Install sound-absorbing wall treatments

Use Acoustic Pro fabric wrapped panels to soften hard surfaces and absorb sound. For a smaller room, use the 40% Rule to figure out how many panels you’ll need (length of room x width of room x 40% = square footage of panels needed). For a larger room, you’ll need to contact us.

2. Rear wall treatment 

The rear wall in a large auditorium or house of worship can produce what’s commonly called slap echoes, or the sharp return of sound. As the speaker’s amplified voice hits the back wall, it is immediately reflected back into the audience. Either cover the entire rear wall with Acoustic Pro sound absorbing wall panels or consider a sound-diffusing treatment.

3. Use the right ceiling shape for your room 

Sound reflections can be useful for speech if they come from the same direction as the speaker and are delayed by less than 30ms. For an auditorium or a large classroom, your acoustics engineer may design a sloped ceiling with acoustic cloud panels to best reflect sound back down to the audience.

How to Treat Reverberations

When outside, high frequency and low frequency sound waves move in a “free field” and decreases by about 6 dB every time the distance from the source of the noise doubles. When inside, hard surfaces reflect sound, resulting in less noise reduction with distance from the noise source. We call this area a “reverberant field”. Without proper acoustical treatments, reverberations can build up quickly in a space making it all but impossible to communicate effectively.

Reverberation time (or RT60) measures the amount of time it takes a sound to decay 60 decibels in a large room after it has stopped. Depending on type of room, you may have different goals a room’s RT60. Rooms designed for speech generally want to be more “dead”, with low reverberation times (sound decays rapidly). Rooms designed for music often have higher RT60 goals, and want to be more “live” with sound reflecting off the walls according to the room’s design.

goal reverberation times by room type
goal reverberation times by room type

One last concept to throw at you… let’s talk about sabins. A sabin is the unit we use to measure sound absorption. For reference, one square foot of acoustic material that absorbs 100% of a sound has a value of one sabin, named in honor of Wallace Clement Sabine. He was able to calculate the expected reverberation time in a room using the volume of the room and the total square feet of absorption (sabins). Developed over 100 years ago, this foundational equation is used by testing labs and reasonably accurate for most architectural work today.

No matter your acoustics issue, many spaces require customized solutions to achieve the desired results. If you are looking for help with your home, commercial, or industrial space, please give us a call — we’d love to help resolve the issue.

Need Help Treating echo or reverb?

No matter your acoustics issue, many spaces require customized solutions to achieve the desired results. If you are looking for help with your home, commercial, or industrial space, please give us a call — we’d love to help resolve the issue.

Timberwool Wood Fiber Panels Solve Reverb and Echo

Timberwool Wood Fiber Acoustic Panels give that beautiful wood aesthetic, while still delivering high-end sound absorption. They can be treated just like wood: cut them to any shape and paint them to any color on your way to a beautiful finish in your space!

  • Absorptive wood creates an attractive aesthetic while reducing reverb and echo
  • Primed and ready to paint any color
  • Custom sizes available
  • Class A Fire Rated

Have questions about your project?

Call us at 1.800.679.8511