Well, similar thing happen with us, during climb than it stopped, during cruise a few times until we rectified our problem. Ours was more like grinding noise with vibrations and it could be heard from FD all the way to third row.
We checked all the parameters- all in normal and green, we changed the pressurisation controllers- no help. We turned the BLWR to OVRD and the noise stopped immediately, back to AUTO and noise started again. After landing told the engineering of the same and after running diagnostics, I was told that the the system should have been in closed configuration but it was actually in open configuration with flaps fluttering and vibrating and creating all the noise. All the indications on the SD was normal. Now the aircraft is flying in MEL.