Given C♭♭4, for example, is that enharmonic with B♭3 (because you start at C4 and flat it twice) or B♭4 (because octave number 4 means octave number 4)?
Asked another way, how do you write the note below in scientific pitch notation?
I'm just wondering from a theoretical perspective.
Follow the note name. Add the accidentals later.
Begin by acknowledging that this pitch is some type of C4. Then add the accidentals to show that it's C♭♭4.
This is a little strange, because (as you say) C♭♭4 is lower than B3. But that's really no more odd than saying any C♭♭ is lower than its nearest B.
And the same is of course true going the other way: B♯3, despite being enharmonic to C4, is nevertheless identified in the "3" register.
