I'm having trouble getting the bass "right" in my new theater --thin at some frequencies and boomy at others. I suspect that my DIY speakers have some response "funnies" I just haven't noticed before. I have access to a Schlumberger response analyzer. It will analyze and plot out the gain and phase transfer characteristics of anything between its output and input. All I need is a good flat microphone to use it for room measurements (and maybe a mic preamp; the Schlumberger accomodates a wide range of input voltages, but microvolt-level inputs may cause noise problems). Josephson has some mics that are advertised to +/-1.0 dB, but they're $500 (ouch). I also have a Rat Shack SPL meter with mic-out jack but it's old (20+ years) and I don't trust it. Are the new ones really flat? Any other ideas?