<p>Human perception of location in azimuth of low frequency sounds (or low frequency envelopes of higher-frequency sounds) includes use of <a href="https://en.wikipedia.org/wiki/Interaural_time_difference" rel="nofollow noreferrer">interaural time differences</a> - this is the phase coding you're talking about. There is some rather specialized circuitry in the auditory brainstem to perform those calculations. Your description of how predatory birds accomplish it is the same as is done in humans - this is an evolutionarily conserved trait in land vertebrates.</p>
<p>At higher frequencies, the time between waves is too fast to estimate phase lags, but the head is better at attenuating sound so intensity differences are used. Wikipedia has a <a href="https://en.wikipedia.org/wiki/Sound_localization" rel="nofollow noreferrer">fairly informative page on sound localization</a> which would be a good starting point for further reading.</p>

CC BY-SA 4.0
2021-12-30T22:25:07.690Z
2021-12-30T22:25:07.690Z
Bryan Krause
<p>In nature when people perceive a point source of audio moving in 3D space say when I am stationary and listening to someone talking who is walking around me does my perception of that audio benefit from resolving out the phase differences in the audio as it is processed and combined knowing I have two ears ? In other words, is human acoustic processing fast enough to be sensitive to phase difference due to separation in 3D space of our ear drums ? Or is localization abilities simply due to amplitude differences due to distance ?</p>
<p>I know some predatory birds earn a living by localizing in 3D space their prey.  They process incoming audio data in a certain location on one side of the brain and the neurons from each ear that transport the audio signal to that brain location are of the same length ( so both neural pathways incur the same temporal delay ) however interestingly this brain location is on one side of the brain and the neuron coming from the ear on the same side of the brain winds back and forth burning up its length in a coil before reaching this audio processing center. Its doing this to maintain phase accurate audio information being received from each ear.</p>
<p><em><strong>UPDATE</strong></em> I will update this to show some back of the napkin maths to zero in on wave length in hearing freq range to reveal the time periods we are dealing with</p>

<perception><computational-modeling><spatial-cognition><auditory-discrimination>
Does human biology compute audio fast enough to benefit from phase accurate audio propagation in 3D space?
Scott Stensland
# Does human biology compute audio fast enough to benefit from phase accurate audio propagation in 3D space?

(Asked by: username_0 on 2021-12-30)

In nature when people perceive a point source of audio moving in 3D space say when I am stationary and listening to someone talking who is walking around me does my perception of that audio benefit from resolving out the phase differences in the audio as it is processed and combined knowing I have two ears ? In other words, is human acoustic processing fast enough to be sensitive to phase difference due to separation in 3D space of our ear drums ? Or is localization abilities simply due to amplitude differences due to distance ?

I know some predatory birds earn a living by localizing in 3D space their prey. They process incoming audio data in a certain location on one side of the brain and the neurons from each ear that transport the audio signal to that brain location are of the same length ( so both neural pathways incur the same temporal delay ) however interestingly this brain location is on one side of the brain and the neuron coming from the ear on the same side of the brain winds back and forth burning up its length in a coil before reaching this audio processing center. Its doing this to maintain phase accurate audio information being received from each ear.

***UPDATE*** I will update this to show some back of the napkin maths to zero in on wave length in hearing freq range to reveal the time periods we are dealing with

**Tags:** perception, computational-modeling, spatial-cognition, auditory-discrimination


---

## 1 answers

### Answer by username_1 on 2021-12-30. Score: 2 | Accepted answer

Human perception of location in azimuth of low frequency sounds (or low frequency envelopes of higher-frequency sounds) includes use of [interaural time differences](https://en.wikipedia.org/wiki/Interaural_time_difference) - this is the phase coding you're talking about. There is some rather specialized circuitry in the auditory brainstem to perform those calculations. Your description of how predatory birds accomplish it is the same as is done in humans - this is an evolutionarily conserved trait in land vertebrates.

At higher frequencies, the time between waves is too fast to estimate phase lags, but the head is better at attenuating sound so intensity differences are used. Wikipedia has a [fairly informative page on sound localization](https://en.wikipedia.org/wiki/Sound_localization) which would be a good starting point for further reading.


---

