Why Does Surround Sound Echo And How To Fix It

Written by
Last update:

Understanding What Is An Echo

While most of us think of the sound of our voice echoing off a canyon wall, we will see and hear the signs of echo every day with a lot of different sounds. The reason we typically don’t see or hear echoes with sounds in our environment is because of the speed of the sound waves. We can perceive that sound is going much faster than what it’s reflecting, and if the sound waves make it to our ears quickly enough, we don’t notice it. If the sound waves take longer than those properties, we will hear the echo just as it bounces back to us. This is the same reason that echo occurs in surround sound.

When we are listening to surround sound, the speakers are sending out sound at the same time. Therefore, if the other speakers in the room, regardless of where they are, take longer than the speed of sound, we will hear the sound that has been reflected off of the other speakers in the room. This will create an echo that can be very obvious and sometimes quite annoying, especially if you are only using one set of speakers to watch TV or listen to music with.

Differentiating Echo vs. Reverberation

Reverberation and echo both happen when sound waves bounce off the walls and other surfaces in a space. But the echoes that you might experience in your surround sound system are different from the reverberation that occurs in an empty room.

Reverberation is the close sound reflection that happens in a space and it gives a recording studio or concert hall its character and distinct sound. In a home theater surround sound setup, reverberation is undesirable, sounding like a hollow and empty space. This makes the sound appear unnatural enough to be unusable in terms of entertainment and general quality. It simply doesn’t sound right.

Echo, on the other hand, is what you hear in your surround sound system, and it is caused by a combination of reflections and reverberations. Each reflection that happens causes the sound to lose its clarity and to become hollow and echoic. Reverberation occurs naturally in the following conditions:

  • When sound hits a reflective object
  • When sound bounces off the walls and floor
  • When sound moves into a space with acoustics

Echo is caused when reverberation overlaps and occurs with other sounds produced by different regions of the speaker.

How Does Surround Sound Work?

If you have ever been to a movie theatre or a concert hall, you've probably felt like you needed just a few more speakers to make the experience truly immersive. Sound moves in waves through the air, and we experience this medium in our daily life. However, it is not so intuitive when it comes to dealing with sound waves. Instead of being focused on a small channel, sound waves expand in all directions. This can be problematic if you are trying to create the effect of "surround sound."

One way to illustrate this concept is by using the example of light. In the case of lighting, you need only one light source to cast light in all directions. This is why light fixtures generally have a broad, wide-angled projection. The narrow beam isn't as effective and since the light source is broad and "high", objects in the room are more evenly lit. The same concept can be applied to sound. You can create a "sound beam" with a high-frequency speaker, but this is essentially the same as using only one speaker. Both light and sound waves travel in all directions, so to create the effect of surround sound, the sound waves must be reflected by the walls and then directed back towards listeners, to capitalize on the whole area of the room for the most possible effect.

Why Does Surround Sound Echo

Without sound treatment, you'll likely encounter some echo problems when using a surround sound system. This is especially true if you have your speakers set up in a smaller listening room that's reflective in nature. To help minimize echo when using a surround sound system, you first have to understand echo.

An echo is basically an acoustic reflection of a sound. These reflections will be heard in the room either as an echo if the reflections occur before the direct sound, or as reverberation if the reflections occur after the direct sound. So, how does this relate to surround sound?

When you're using a surround sound system, you are likely using at least 5 speakers. These speakers are spread around the room to create a 360-degree sound field. If any of these speakers are set up in a location where sound waves, after reflection, reach your seating position before the direct sound, you will experience some echo.

Imagine the sound reflects off a flat surface and then bounces back the same distance and direction as the direct sound. This reverberation would occur after the direct sound due to the distance covered by the reflection.

Out Of Phase Speaker Setup Problem

Sound waves are not an endless series of compressions and rarefactions – they come in groups of three, known as a cycle. When you play a sound through a single speaker, the cycle of compressions and rarefactions oscillate in three dimensions and then return to the start point (the speaker), which we hear as the sound we associate with that speaker. For listeners to hear (what they interpret as) a realistic sound, the sound waves produced by each speaker need to arrive at the same time at the listener's ear. Because the volume of the sound is strongest when it’s farthest away from the start point, the sounds from all of the speakers must be in the same phase with each other and balanced out against each other. This is why it’s important to integrate all of the speakers before you listen to them, to make sure that all of the speakers are the same distance from the listener's ear.

It can be very difficult to balance out a surround sound system if the speakers are even slightly offset from each other.

Resolving An Out of Phase Speaker

One of the most common surround sound issues is when audio sounds like it floats back and forth between speakers. This can happen when two or more speakers are out of phase. To fix an out-of-phase issue try the following steps:

  1. Make sure all your speakers are connected properly. If you're having trouble with the audio, then the issue might be with a loose connection.

  2. Reset your speakers. To reset your system, do the following:

For a 5.1 surround sound system, press these buttons simultaneously:

  • Volume Down (the button farthest to the left)
  • Input Down (the button in the center)
  • Mode Down (the button furthest to the right)

For a 7.1 surround sound system, press these buttons simultaneously:

  • Input Down (the button in the center)
  • Volume Down (the button farthest to the left)
  • Mode Down (the button farthest to the right)

You can also reset the speakers one at a time.

Fixing Surround Sound Speaker Wiring

Room acoustics can be a big factor in your surround sound speaker reproduction accuracy. However, the ideal situation is when your speakers, amplifier, and subwoofer are correctly wired, and the acoustic environment is optimized. I don't know about you, but I've never had a room that's properly wired for surround. So what do you do? Well…..

Check speaker connections at the back of the receiver and then at the speakers themselves. This will help you identify that the wiring has not been "crossed". The problem could be the speaker cables.

Twisted speaker wires that cross each other can cause interference problems that lead to distortion, especially at higher volumes. Try using a different set of cables or switch the speaker cables at the receiver or speaker to make sure they are not crossing each other. Try a new set of cables. (If you have a receiver/amplifier with detachable speaker cables, try a set of high-quality "banana" cables.)

Understanding Bad Audio Dampening

Sound is much like water. When it encounters something it simply bounces off, much as a simple puddle would after being dropped onto the sidewalk. However, when sound hits a reflection, it doesn't bounce off as easily. This is because the reflection disrupts the consistency of the water. Sound waves are less affected by non-solid objects, so they bounce off at various speeds and angles.

If you have read much about surround sound in a room, you have probably read words used to describe the process, like reverberation, anti-reverb, and echo. These words aren't necessarily enough to describe the types of sound dampening that should be done to a room to get the best result, though.

Sound dampening is necessary for both the walls of the room and the sound reflection off the ceiling and floor. Sound-absorbing materials absorb some of the sounds and stand-alone baffles prevent sound from bouncing, but they may also be combined for the most effective use.

Materials That Create Echoes

Materials such as walls, floors, and ceilings can cause echo that you hear as reverberation or echo. If the materials are not dense enough to absorb sound, sound waves can bounce back and forth between the two materials causing an echo.

An echo is created when a sound wave bounces off of a surface other than the surface of the sound originated. This surface can be something as small as a desk or as big as a wall extending through to part of the floor or ceiling.

Sound waves that resonate with other objects cause echoes. A space that is open and has a hard-surface floor, walls, and ceiling will reflect most of the sound waves that have not already escaped into the surrounding air. The open space is a good environment for creating echo and reverberation. When echo is severe, the space is considered to be very reverberant.

Solving Home Theater Room Echoes

As long as it’s happening, there’s no way to avoid it. Sound is simply energy that needs to go somewhere, so it bounces off all the surfaces. This includes the walls, floor, and ceiling in your room and more if you happen to have hard surfaces in your home theater room.

The most noticeable echo is going to be from the hard surfaces like the floor and the ceiling. The sound waves bounce around at different frequencies and, when the waves echo back, it can create a disruptive echo effect. This is why they say it's better to have different types of surfaces like carpets, throw rugs, curtains, low-pile fabric, etc.

Sound echoes are caused by hard surfaces that are perpendicular to a speaker. Light reflects off a surface in the same way sound does. It is easier to see the reflection off a countertop, white ceiling, white walls, etc. Try not to place large mirrors along the walls by the speakers. It will reflect sound and cause a devastating echo.

Conclusion

The best way to combat echo is to improve the quality of your sound. Using surround sound will improve the overall audio quality and make your viewing or listening experience a joy!

Similarly, if you are looking for the best home theater system possible, the key will be to find the best sound manufacturer with the best customer service and support team. This means you won’t have to spend a lot of time and effort researching and finding the right products alone.