Maintaining constant amplitude with bandwidth limited pink noise

[dcibel]

Hello,
This is hopefully a stupid question. Is there an easy method to maintain equal amplitude when limiting the frequency bandwidth of pink noise using the generator? For example, If I set 90dB SPL for a "speaker cal" signal that is limited to 500-200Hz, then change to a full range signal, SPL of the full range signal is reduced even though the output level is the same. I assume the variation is due to the fact that pink noise is not constant power over frequency, so can the level be set for -12dBFS at 0Hz even though the signal is limited to 500Hz and up?

Simple example below. I would like to complete some bandwidth limited testing using pink noise, but without the shift in amplitude. As it is, I am making some manual adjustment in level for each filter applied on the generator, and I have to think "there must be a better way"

Thank you.

 

[John Mulcahy]

The spectrum level changes to maintain the requested rms level over the narrower bandwidth. I am currently working on another measurement method which provides a post filtering option for the excitation, so the spectrum stays at the same level in that case.

 

[dcibel]

That's great news John, exactly what I'm looking for.

(While looking at measurement methods, periodic noise in the measurement window? )

 

[John Mulcahy]

periodic noise in the measurement window?

Nope.