I was messing about....I left the doors open here, Room Noise . AC, Fans in the other room etc..
Setup the SM7 into the Grace Design preamp> Antelope Interface Line In> then spoke into the SM7 until it was a normal -6 ~-10 on the DAW.
Thought about Room Noise- and Mic Sensitivity.....so I did a quick Room Noise with the mics I had in arms reach..
The audio clip is short but goes through a WA47tube, AGA414 Flat setting, MXL V67, Shure KSM32, AKG P420, Shure SM7, AKG 414 with Full Pad(18db reduced) , just a normal day Room Noise with the mics all plugged in and out aka "IDLE" aka "background noise" and showing the benefit of a SM7b in a somewhat noisy room with very little effort and getting up close to the mic, it works.
Picture shows the DAW scale meter, the BlueCat Freq chart to show the freq;s ...as some Mics, get the room noise as more bass or more higher freqs.
WA47- 32mv/pa / -30dBv/pa (most sensitive)
AKG 414 flat 23 mv/pa / -33dbv
MXLV67 15mv/pa / -36.5 dBV
KSM32 16mv/pa / -36dBV
AKG P420 28mv/pa / -31dBV ( same as U87AI)
SM7 1.12 mv/pa / -59 dBV (least sensitive in bunch)
AKG 414 Full Pad 2.9mv/pa / -50.8 dBV (full pad = least capsule voltage 18 reduction)