I have an Audio Control Equalizer, Spectrum Analyzer, and Pink Noise Generator that I bought in 1983. It generates pink noise and has a mic for the purpose of determining the difference between the signal going in (pink noise) and the signal coming out through the speakers so I can adjust frequency levels and thereby be assured that what is going in is also what is coming out. Does anyone know where I can find such an equalizer today? I've found several older ones from the 1980s but the mics for all have been misplaced. Any ideas would be helpful. Thanks.