The intensity of a wave is proportional to the square of the amplitude of the and the frequency of the wave given by the equation:
$$I = \frac{\overline{P}}{S} = 2\pi^2\rho vf^2A^2$$
Now when talking about sound waves the sound level of a noise (loudness), it is proportional to the intensity of the source. If intensity of a wave is proportional to frequency, why doesn't sound level, in general, depend on frequency. i.e. Higher frequency, higher intensity, higher sound level.
Why is this not the case?
For example if you change the frequency of a sound wave from 500Hz to 15000Hz, this won't necessarily be perceived as a change in loudness. But hasn't the intensity of the sound increased, because the frequency has increased? The loudness of a sound does not seem to depend on frequency. But according to the equation above, intensity DOES depend on frequency. So why does it not change perceived loudness?