Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Does loud voice mean high frequency?

  1. Jun 22, 2015 #1
    As I know: Velocity of sound = wavelength x frequency. If frequency increases wavelength decreases. So even if you shout loudly the velocity of sound wont change only that you will hear a louder voice.

    So does that mean that louder voice has higher frequency?
     
  2. jcsd
  3. Jun 22, 2015 #2

    Drakkith

    User Avatar

    Staff: Mentor

    A louder voice has higher amplitude sound waves.
     
  4. Jun 22, 2015 #3

    davenn

    User Avatar
    Science Advisor
    Gold Member

    Then you know incorrectly

    speed of sound is dependent on the temperature, pressure and density of the material it is travelling through, be that air, another gas or a solid. The speed (velocity) of a sound wave in a idea gas is independent of frequency but for a real world gas, the frequency does add a slight variation

    The amplitude of a sound wave is independent of its frequency
    Think of a piano or other instrument playing a single note ( single frequency)
    it can be played louder or quieter but the frequency of that note doesn't change

    you can even take that a step further. you listen to the radio or the TV I assume ?
    when you turn the volume up and down the frequency of the sound doesn't change, aye ?
    you don't hear the news readers voice changing pitch with a change in volume :smile:

    Dave
     
    Last edited: Jun 22, 2015
  5. Jun 22, 2015 #4
    You are right. The velocity of sound depends on the medium. So now we are in need of a formula of velocity of sound that takes into account the medium (Hot air, Water etc). Could you give out such a formula?
     
  6. Jun 22, 2015 #5

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2016 Award

    Isn't this now a different subject than the topic you started with? You never acknowledge if you had finally understood what "loud" corresponds to in wave mechanincs, so it isn't clear if you have understood THAT part of it before opening another can of worms.

    Secondly, have you done a preliminary search on those relationships?

    Zz.
     
  7. Jun 22, 2015 #6
    From what I understand: The longer the wavelength, the lower the frequency. The 'height' of the wave is its amplitude. The amplitude determines how loud a sound will be. Greater amplitude means the sound will be louder.

    Now coming to my previous post. As far as I know that if we were to calculate speed of light in water as the medium we would use the refractive index of water. But what would we use in case of velocity of sound?
     

    Attached Files:

  8. Jun 22, 2015 #7
    A table like this, for example:
    http://hyperphysics.phy-astr.gsu.edu/hbase/tables/soundv.html

    Usually for sound the speed is tabulated directly whereas for light the index of refraction is more common.
    There are formulas that relate speed of sound to the properties of the medium, too. But they depend on the type of medium (solid, gas, liquid, bulk or guided, etc)
     
  9. Jun 23, 2015 #8
    I think that I have found the formula that I need. Formula of velocity of sound in water = c = (E / ρ)1/2 .
    Where
    E = bulk modulus elasticity (Pa, psi)

    ρ = density (kg/m3, lb/ft3)
     
  10. Jun 23, 2015 #9
    To summarize I would say that loudness depends on amplitude and amplitude is independant of the frequency or wavelength. Am I right?
     
  11. Jun 23, 2015 #10

    Drakkith

    User Avatar

    Staff: Mentor

    I believe so.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook