I've been experimenting with testing microphones. I used a Scarlett interface into my laptop and Friture to produce Mel & A-weighted spectrograms.
I used a HH Vector 8" producing pink noise over bluetooth as a sound source.
Speaker and mic 1.25m apart and 1.25m above the floor in large room with lots of soft furnishings, curtains.
Most obvious thing was the speaker had limitations, as you could see the same notches across all the mics.
The flatest response was... a £30 generic BM800 mid-sized condenser microphone. Often used with 5V from a PC, these run well on 48V phantom power and are very sensitive. Lots of hacks for their circuit or putting larger inserts in them. I haven't modded this yet, but it gave the biggest signal and flattest curve with widest frequency response of all the mics I tested...
I think this gives the best idea of the HH Vector's output. Note the dips at 4500 and 5500Hz which I guess may be the crossover frequency.
My other condenser mic - Behringer C2, used flat and with low cut, which drops around 3dB from around 1000Hz ish. Interestingly the 5500 dip is not very pronounced.
I think I need a better white noise source before repeating the experiment... things are going on for different types of mic, but I don't have confidence the sound source is flat enough to draw meaningful conclusions on anything but the sensitivity and the extent of the high/low frequency response.
If anyone can recommend the ideal spectrogram settings, better software (Friture has no manual and appears to lack a simple save screenshot function) or any advice at all, all welcome!