that was the start of it. the offset otic openings result in differential arrival times of the acoustic peaks, thus phase differential.
neurosynaptically, there is no phase, there is frequency shift corresponding to presynaptic intensity, and there is spatio-temporal integration of these signals. temporal integration is where "phase" matters
its all a mix of "digital" all or nothing "gates" and analog frequency shift propagation of the "gate" output.
its all made nebulous by the adaptive, and hysteretic nature of the elements in neural "circuitry"
This device in this article seems to be mainly for serving signal outside of the building. However, devices like the one you descibe exist, such as:
https://pivotalcommware.com/echo-5g/
In physics, different frequencies don’t interfere with each other—they're always independent. However, in digital operations and mathematics, this isn’t automatically true, so we need to carefully select the right frequencies.
OFDM leverages this by ensuring that, in the frequency domain, certain frequencies remain completely separate, meaning changes to one frequency (in amplitude or phase) won't affect the others.
This allows us to capture the maximum information with limited samples.
I wasn't clear : phase shift has a clear example: think of two sine waves, one whose value at time t is sin(t) and the other sin(t+pi/2). they'd have the same period, and frequency, but would be phase shifted by that addition in the time parameter.
For another fun example, here's the residential power in current American homes: two 120v A/C feeds, out of phase so that you can combine them in the breaker box to get 240v A/C.
I’m aware of how ANC works. It uses the same frequencies with reverse amplitude. The comment you objected to however was talking about different frequencies.
Right? One of my dumb noobie questions has always been why textbooks explain ANC as "180 phase shift" instead of "reverse amplitude". Do they really do an entire DSP pass to break apart a signal and phase-shift it just to get the output that a minus sign could get? There must be something missing from the plum-pudding model.
It's only a sign flip when the detector and emitter are perfectly in phase. Adding delay causes the required phase shift will drift slightly. Also note that the phase offset of a delay is frequency dependent, so this drift will be as well.
Another reason is that devices and materials have different frequency responses, so an external signal needs to be filtered to match the levels in the device.
Owls use asymmetric skull structure which helps them in spatial perception of sound.