So I understand the basic principles behind noise cancellation. You essentially use a microphone to record incoming sound waves and create an inverse wave that destructively interferes with the initial wave, thus, cancelling it out. But I don’t understand, practically, how this is done.
Let’s assume the sound wave makes contact with the microphone in the AirPod, which analyses the wave and shoots out an inverse wave, but by that point – the initial sound wave would surely have already reached my ears. The AirPod basically needs to cancel the sound wave before it moves roughly a centimetre or it’s too late.
The speed of sound (in a standard environment like air) is 343 meters per second or 34,300 centimetres per second; this means the AirPod has 1/34,300 seconds or ~0.03 miliseconds to do these operations to cancel the wave. That just seems absurd to me for such a tiny chip in the bloody AirPod.
Someone fix my confusion please.
In: 678
Audio signals move throw wires much much faster than the same acoustic energy would move through the air.
This is why, even in small rooms, when you have several sets of speakers that are at difference distances from the front or stage area, you need to actually add audio delay to the speakers that are farther away. The audio will travel faster through the wires to the speakers and get there before the same audio naturally carries from the stage. And I’m talking like….30 feet.
So yeah it’s totally plausible that the audio will travel through the tiny bit of wire from the mic to the speaker before the natural acoustic energy gets there.
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