# What causes that seashell "ocean" sound? **URL:** \ **Category:** Factual Questions\ **Created:** [July 12, 2003, 4:03pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982 "2003-07-12T16:03:47Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Zenny](https://avatars.discourse-cdn.com/v4/letter/z/ad7895/32.png) [@Zenny](https://boards.straightdope.com/u/Zenny)\ **Post date:** [July 12, 2003, 4:03pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/1 "2003-07-12T16:03:47Z")
I have nothing to add. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [July 12, 2003, 4:42pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/2 "2003-07-12T16:42:24Z")
There are two theories: 1. It’s caused by the reverberation of ambient noise inside the shell. 2. It’s caused by sounds generated within the body. These include blood rushing around, the heart pumping, and muscular vibrations. I personally think that theory (1) is bullshit, and easily disproven by simply pressing a hand over one ear, but there’s still a lot of support for it. This would make a good topic for **Cecil**. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [July 12, 2003, 4:48pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/3 "2003-07-12T16:48:49Z")
I’m just the opposite. Try using objects of differing dimensions and you’ll hear a definite change in the overall pitch of the sound you hear. I just tried it with a tall cup and a short jar, and the sound I heard using the jar was of a higher pitch than the cup, as I would expect. Unfortunately, I don’t have access to an anechoic chamber to further test this theory. Agreed, I’d like to see **Cecil** answer this one as well. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [July 12, 2003, 5:02pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/4 "2003-07-12T17:02:47Z")
Changing the size of the chamber _does_ affect the sound you perceive. The chamber acts a filter. But what’s the original source of the sound? Is it outside or inside the body? Try it again, this time clenching various muscles while you do it. Jaw muscles, stomach muscles, pectorals, etc. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 12, 2003, 5:17pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/5 "2003-07-12T17:17:59Z")
A bit from both columns. The traditional explanation is ambient noise filtered by the resonant cavity of the shell / coffee cup / etc. I think a very large part of the noise source is your own circulation, but I doubt that it’s exclusive. Another point to observe is that you can cancel the effect by holding the coffee cup tightly against your head, obtaining a good seal with no place for air to escape. At that point, you may still hear sort of a low grade “train rumble” (your circulation), but no “ocean”. My vote is that in typical circumstances 90 percent of the sound is contributed by your own body. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [July 12, 2003, 5:33pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/6 "2003-07-12T17:33:21Z")
I did actually research this question years ago, and I’ve forgotten most of it now. :smack: There’s a third factor involved, about how the ears are set up to cancel out or ignore the internal body noise, and that placing the shell near one ear interferes with that process. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [July 12, 2003, 5:33pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/7 "2003-07-12T17:33:49Z")
I hear almost nothing if I seal the cup tightly against my head. I conclude, therefore, that most of the sound is coming frrom sources external to you. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [July 12, 2003, 5:39pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/8 "2003-07-12T17:39:00Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*I hear almost nothing if I seal the cup tightly against my head. I conclude, therefore, that most of the sound is coming frrom sources external to you. \*\* The frequency gets lower as you bring the cup closer. The sound remains even after the cup is pressed firmly to your ear. Use your palm instead. That makes the effect more obvious. ---
**Author:** ![Zenny](https://avatars.discourse-cdn.com/v4/letter/z/ad7895/32.png) [@Zenny](https://boards.straightdope.com/u/Zenny)\ **Post date:** [July 12, 2003, 5:45pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/9 "2003-07-12T17:45:39Z")
No, I don’t want Cecil to answer me. If I wanted an answer from him, I would have mailed him. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [July 12, 2003, 6:07pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/10 "2003-07-12T18:07:26Z")
> [@](#): > > \*Originally posted by Zenny \* > \*\*No, I don’t want Cecil to answer me. If I wanted an answer from him, I would have mailed him. \*\* Huh? ---
**Author:** ![Zenny](https://avatars.discourse-cdn.com/v4/letter/z/ad7895/32.png) [@Zenny](https://boards.straightdope.com/u/Zenny)\ **Post date:** [July 12, 2003, 6:09pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/11 "2003-07-12T18:09:28Z")
What’s hard to understand? ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 12, 2003, 6:17pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/12 "2003-07-12T18:17:43Z")
Nothing. It’s just an unusual attitude. If you wrote to Cecil, you would likely not get an answer, or just an acknowledgement from Ed Zotti without answering the question. Or it would be a long time before it surfaced as an article. However, it’s rather surprising that you would not want that to happen. Then again, you may take satisfaction in making me look like a perfect idiot this morning, holding a coffee cup over my ear at various angles. Fortunately, nobody was around to see it. ---
**Author:** ![Zenny](https://avatars.discourse-cdn.com/v4/letter/z/ad7895/32.png) [@Zenny](https://boards.straightdope.com/u/Zenny)\ **Post date:** [July 12, 2003, 6:36pm UTC](https://boards.straightdope.com/t/what-causes-that-seashell-ocean-sound/187982/13 "2003-07-12T18:36:11Z")
I don’t need Cecil to set me free, set me free, I need someone else to set me free, set me free. 🙂