Beats audio acoustic echo cancellation
Small rooms have a short delay and larger rooms have larger delays. The room acoustic delay, also known as echo path delay, is a measure of the time in milliseconds it takes the signal to travel from system loudspeaker(s) to bounce around the room and be picked up by the system microphone(s). Typically, the larger the room, the longer the acoustic delay will be. If there is no echo canceller circuit to eliminate this acoustic return echo signal, the remote participants hear their voices delayed in time in their earpiece-kind of like what happens when you yell into the Grand Canyon.įigure 1c: The sound emitted from each speaker takes a different path (room bounce) to each individual microphone, creating a unique acoustic echo path delay for each microphone. If this effect is not dealt with, an acoustic return echo signal is generated. When a sound is produced by conference system speakers, it bounces around the room and is picked up by the system microphones as illustrated in Figure 1a. The person at the far end of the call does not hear this echo as you do, so if the person starts talking before the return echo has dissipated, you will hear both your echo and the other person’s voice at the same time. Now, if this phenomenon happens to you during a conference call, it does not take much imagination to realize how bothersome this will quickly become, resulting most likely in listening confusion and poor intelligibility of the voice from the far end. If the echo is really bad, you might hear the same phrase echoed back at you more than once. Say you are at the Grand Canyon and you yell out the words, “hello out there!” Sometime later you will hear the same words echoed back at you, say maybe half a second to a second later.
Acoustic return echo is the effect of callers hearing their voices in their headset speaker delayed in time after they have spoken, which sounds just like the echo you may hear in a canyon or very large room.