Both white and pink noise are considered broadband noises. Both of them are made of all frequencies that are audible to humans, so all frequencies anywhere between 20 and 20000 hertz. But the way their signal power is distributed among all frequencies radically differs, and you can see that using a power analyzer or just by looking at the simple sound spectrum graphs provided below.

Therefore, at lower frequencies, the octave bands are narrower, and at higher frequencies, the octave bands are wider. To help you grasp this concept better, the table below shows the typical octave bands used in acoustics and the frequency range contained in each band. The numbers make it very clear: the 8000 hz octave band regroups a lot more frequencies than the 63 Hz octave band.




Low Frequency White Noise