If you lived on a planet with a very thick atmosphere, and you communicated verbally, what frequency range would be best? What would you eventually evolve to?

Would their voices need to be high pitched or deep bass? ultrasonic?

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    $\begingroup$ Welcome to the site Ralph Rotten, when you have a few minutes, please take the tour and read up in our help center about how we work: How to Ask. Could you explain what you mean by "thick"? Are you asking about high atmospheric density? You would also need to tell us the atmospheric composition, ie the mixture of gasses. Different gasses have varying speeds of sound at different pressures. Voting to put on hold as "unclear what you are asking" in order to give you time to edit your question. $\endgroup$ Jun 24, 2019 at 15:50
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    $\begingroup$ Welcome to Worldbuilding! We're glad you could join us! When you have a moment, please click here to learn more about our culture and take our tour. As written, this question is going to get closed as too broad or primarily opinion-based just for the question "what would you eventually evolve to?" Stack exchange is one-specific-question/one-best answer. What one, specific question do you have? (what they evolve into is not specific.) $\endgroup$
    – JBH
    Jun 24, 2019 at 15:52
  • $\begingroup$ How thick is very thick? Is Earth's atmosphere thick or is it thin? Can you describe the atmosphere with more specific words -- what's the pressure, temperature, gas composition? $\endgroup$
    – AlexP
    Jun 24, 2019 at 16:39
  • $\begingroup$ Hi Ralph, this is not a bad question, it just needs more details so we can answer it. Don't worry about the question getting closed; if you edit it well, we can vote to reopen it. The "on hold" period is to give you time to make it a stronger question. $\endgroup$
    – Cyn
    Jun 24, 2019 at 17:28
  • $\begingroup$ Note that air density won't affect anyone's hearing, so whatever frequency range is "best" will have to be within the normal human range, say 40 to 8000 Hz. $\endgroup$ Jun 25, 2019 at 0:31

1 Answer 1


You could have a read of this section of an article on outdoor sound propagation: Attenuation by atmospheric absorption (or a vaguely related physics SE question which brough that article to my attention). There are some fairly hairy formulae in there, and an important caveat "The formulas, are valid for a pressure under 2 atm, a temperature under 330 K and up to an altitude of 3 km" but one may extrapolate from that, especially as you're not asking for hard science.

TL;DR: the absorption coefficient is higher for a higher frequency and/or a higher pressure.

High frequency sounds will carry less well in higher pressure air. If you want to be able to shout as far, you'll need a deeper voice. I can't tell you which frequency range would be best without knowing about the atmospheric composition and pressure, and what metrics you'd use for "best" anyway.


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