Post by thread:[OT] audio (LF?) phase detecting

Hello all, this is *really* offtopic but really you know more about electrothings than the others so here is it.. I need/want to build a high directivity sound outdoors microphone, in a fifty-fifty challenge/savemoney basis. I want to build it from two or three electret mics (or four.. I really want to be able to pinpoint the noise source), adding amplitudes on on-phase signals and rejecting out-of-phase signals. The problem is.. where I could locate some info about op-amp circuits and mechanical/lambda mic distance needed, or simply something related to this subject?. I remember an elektor magazine issue of the last year regarding this kind of device (where I picked the idea) but I do not have that issue, and I do not have a easy way to get it. As usual, thanks in advance and keep on PICing Sebastian PS: Only this time.. I think that analogic electronics are better. DSP's are a bit far for me yet.