# How do we detect that a sound source is far away? **URL:** \ **Category:** Factual Questions\ **Created:** [November 29, 2005, 9:32pm UTC](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269 "2005-11-29T21:32:37Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [December 1, 2005, 4:26am UTC](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269/21 "2005-12-01T04:26:33Z")
Matt, your cites are interesting but I guess I’m missing something. How is the timing difference going to determine distance? I can see it being used to determine direction. But assume the sound is coming from a source at a forty five degree in front of and to your right. The difference in timing between your left and right ears will pick up the direction. But how will the timing be influenced by whether the sound is ten feet away or a hundred feet away? Wouldn’t the difference in timing between your ears will be the same regardless of how far the sound travels before reaching you? ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [December 1, 2005, 7:31am UTC](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269/22 "2005-12-01T07:31:32Z")
> [@Little Nemo](#): > > Matt, your cites are interesting but I guess I’m missing something. How is the timing difference going to determine distance? It doesn’t, as far as I know. I was adding to the exchange between **Blake** and **CurtC** : > [@CurtC](#): > > From my armchair understanding of the workings of the ear and brain, it’s just not wired to measure the timing of events between the two ears. Your brain could do it in software, but its response time is much longer than the fraction of a millisecond difference in the time your ears hear the same sound. No, the direction-finding is by processing the subtle resonances of the outer ear, especially when you turn and shift your head. My second cite specifically indicates that this was a perfectly reasonable deduction. It just turns out to be untrue. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [December 1, 2005, 7:34am UTC](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269/23 "2005-12-01T07:34:43Z")
> [@](#): > > If this were true, a person would be unable to determine the distance of a sound if it was anywhere on the plane midway bewteen the ears and perpendicular to the axis between the ears (ie, directly in front of you, directly overheard, etc). Is that the case? I would assume this might be true, but I’ll admit I don’t really know. ---
**Author:** ![BobT](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@BobT](https://boards.straightdope.com/u/BobT)\ **Post date:** [December 1, 2005, 5:50pm UTC](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269/24 "2005-12-01T17:50:11Z")
A real life example of this problem for me came one sleepless night when I was woken up by a high pitched whine that was coming from … somewhere. It wasn’t in my home. I checked all my appliances. I assumed that in my apartment building that some vacant unit had an alarm clock in it and it was going off. But that wasn’t it. Eventually I realized that the sound was coming from a power line near my house. For some reason, the lines were giving off a whining sound. From my room, the noise was piercing, but it was less so when I was standing outside next to it. And I can say that if the CIA wishes to use that sound as a form of torture on me, I will break very quickly. [Previous page](https://boards.straightdope.com/t/how-do-we-detect-that-a-sound-source-is-far-away/333269.md?page=1)