1
$\begingroup$

How do I determine/calculate the air pressure emitted from a speaker ? And how to determine the velocity of air from the sound air pressure ?

$\endgroup$
1
$\begingroup$

You need to measure the sound level in decibels. This is a logarithmic scale where zero decibels corresponds to a root mean square pressure of 20 micropascals, and every 20 decibels corresponds to a tenfold increase in the pressure.

Once you have measured the sound level and calculated the pressure you can use the equation for the particle velocity:

$$ v = \frac{P}{Z} $$

where $Z$ is the acoustic impedance. The linked article includes a table of values for the acoustic impedance of air. For air at sea level and room temperature the acoustic impedance is about 415 Pa s/m.

$\endgroup$
  • $\begingroup$ So the particle velocity equals to the velocity of air? Thanks for the response. $\endgroup$ – Alan Alexander Nov 30 '14 at 14:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.