you might also try to look after a used audio-technica ATM33a, they can run on battery. so if the analyzer can't do phantompower (48V) it will still work.
My point with the mics are they are cheep and better than what the BSR Sa3x needs, that way it is not the mic that mes up the redings (bottleneck theory). In general you can use just about any mic, but you don't know how the mic works together with the analyzer. 3dB on the scale is about 30% more or less of the level you hear, so if the mic is a little of... well... It do not take much before the analyzer just becomes a bunch of blinking lights you can't use for anything than blinking - you're ears are a much better device.
An idea... hmm... well if you don't need all the fancy blinking lights I have sugestion. You need a tone generator with a sweep on it (you might download a wav file from the net and burn it to a CD instead), then you need a SPL meter (radiohack has one cheep $50). Put the meter on A weight, place the meter in the room, play the sweep and wach the meter. If the level goes up from avage you have a peak, down you have a dip. Just make sure the sweep is not too fast since the meter also needs some responce time.
Sorry if i am a bit harsh on the analyzer/EQ thing, I have just seen too many blinking lights stopping people from using there ears.
