You can find pink noise wave files to download ... I've attached a short mp3 of pink noise. I simply put the pink noise file in an audio track in my DAW and directed the output to my BG250 --- then I sent the XLR output from BG250 (there is a pre/post EQ button - you want it lit so you are getting the BG250 EQ) into a different audio track in my DAW and put a plugin on that track to display the spectrum (it's a free spectrum analyzer plugin). There may be better tools out there, but this is the one I used: Spectrum Analyzer
Thanks a lot! I will try to do the analysis and I will post the results in here for the 115 combo.