There it is again, that unbelievably annoying high pitched sound. What is it? One person says it’s an echo, another person says it’s a reverberation and yet someone else is saying it’s feedback. All I know is it’s driving me absolutely crazy and somebody just needs to make it stop!

If you video conference on a regular basis, chances are you’ve been in a similar situation. People are throwing around different terms left and right then arguing over whose side is at fault. With all of this going on it can be difficult to determine exactly what the problem is let alone how to fix it.

Here’s a quick overview to help distinguish between echo, reverberation and feedback along with some tips to help reduce each one.

Echo, also known as reverberation, is almost always a problem on the far end of a video conference and is the result of a reflection of sound. When a participant speaks into a microphone, the audio gets transmitted to the other side through their speakers. Then, their microphone picks up the audio and sends it back to the speakers in the local room. Participants in the local room hear what was just said again since the speakers on the far end are not cancelling out the audio properly.

To minimize reverberations, an echo canceller or acoustical ceiling tiles can be installed. Additionally, minor adjustments to the type and placement of room furniture along with the installation of shades or a heavy rug can help improve acoustics in the room.

Audio feedback, on the other hand, is almost always an issue with the local room. It occurs when a sound loop exists between an audio input (microphone) and an audio output (speaker). Essentially, when a participant speaks the audio passes through a microphone to the speakers and gets amplified. The process continues to repeat as the microphone picks up the noise, amplifies it further, and passes it through the speaker. Eventually a sound, ranging from a low pitch to an extremely high pitch, is emitted which can disrupt the conference in addition to be extremely annoying.

To minimize feedback, microphones and speakers should be spaced appropriately and positioned so the speaker output isn’t feeding directly into the microphone. Additionally a digital feedback eliminator or noise filter can be installed to reduce feedback.

Audio quality plays a significant role in the video conferencing experience and should not be taken lightly. Poor audio can detract from the effectiveness of the meeting as participants are focused more on trying to hear speakers and tune out background noises than on the topics being discussed.

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There are several different components that go into designing an optimal collaboration space: displays, video switching, control system, lighting, the list goes on. But what about the acoustics, how do you ensure both local and remote participants can hear each other clearly?  Believe it or not, there are actually several factors that affect the sound quality in a room.

Speaker and Microphone Placement:
Room design and they way participants actually use the space must be considered when designing audio pickup and coverage in a room. The style of meetings, along with furniture placement (tables/chairs/displays/etc.), allows a design engineer to determine the best type of microphone and final microphone placement. Most audio visual rooms now perform multiple roles; a single room can be used as boardroom in the morning, then a training room with remote participants in the afternoon. Therefore, microphones may be placed in the ceiling with a wireless lapel and handheld support. This allows multiple room configurations while keeping the technology in the background; allowing the meeting in each scenario to take precedence. Additionally, the speakers selected should allow for full and even coverage of the space; supporting audio from participants, DVDs or PCs.

Room Acoustics:
The acoustics of a room are determined by the room environment; such as room size and shape, ceiling height, surface materials (wall/floor/ceiling) and participant seating locations. The microphones, speakers and screen surfaces may also add a positive or negative acoustical impact into the room. Additionally, noise generated from an HVAC system must be taken into consideration when designing a collaboration room. A noise diffuser can be used to minimize air handler noise in the room.

Reverberation:
Sound reflections can be attributed to the shape of the space, as well as, surfaces located in the room. Hard surfaces, such as paneling, concrete, doors and whiteboards can reflect sounds creating echo and secondary audio throughout the room. Small adjustments to room shape or absorptive surface treatments placed in strategic locations, along with an echo-canceller, can help eliminate reverberation and reflection issues in some of the more difficult spaces.

Windows and Doors:
Background noise can be extremely distracting to both remote and local participants. Selecting windows and doors that minimize outside sounds can help keep participants focused and ensure clear audio is delivered to remote participants. Wall and ceiling structure should also be considered during construction, this will ensue that the meeting stays in the room and does not “leak” in to the next meeting room or the hallway. Additional ceiling insulation, double walls, or specific sound absorbing material can be installed for corporate privacy or high noise areas.

Learn more about creating an optimal collaboration environment from our Audio Visual Buyers Guide.

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