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From my very basic understanding of microphones, they generate a tiny bit of electricity as the membrane moves, this is the signal. It would stand to reason then, that if I connect a bunch of microphones in series, the voltage of the signal would be multiplied and I get a stronger signal, right?

Problem is, I don't know where the noise is coming from, is it mostly from the membrane as well? Or perhaps the wires or some other components? Basically, would combining microphones in series be an effective way to get a better signal to noise ratio?

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  • $\begingroup$ A microphone turns sound into electrical signals, so you probably don't want to connect multiple microphones in series. Are you maybe thinking of having a series of microphone-speaker-microphone-speaker...? $\endgroup$ – DanielSank Jun 6 '16 at 14:48
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    $\begingroup$ What you are looking for is not a stronger signal (i.e. more voltage or current), but a higher signal-to-noise ratio. It is, indeed, possible to increase the SNR by up to 3dB by using 2 identical microphones and by up to 6dB by using 4, however, there will be a price to pay in terms of directional characteristics, which, as in case of directional microphones, may actually be highly desirable. In general, though, if a microphone is not sensitive enough, using a better suited microphone with the properly matched preamplifier will be the better idea. $\endgroup$ – CuriousOne Jun 6 '16 at 14:50
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Several considerations for signal detection problems:

  • Noise comes from many sources. White noise ("static") comes from the random thermal motion of internal circuitry, and will only be increased by adding more circuit elements or wires.
  • Adding multiple microphones could, in principle, increase the measured signal power provided the signals were in-phase, otherwise destructive interference could occur and lower the signal-to-noise ratio (SNR). Unless you can precisely control the phase shifts of the microphone transducers (which would require precise control over the design of the coil windings, magnet size, etc., as well as placing the microphones within a small fraction of the smallest wavelength of one another which is approximately 17 mm for a 20 kHz signal on the high frequency end of human hearing as well as controlling the cable lengths), then you cannot guarantee increased SNR. It could add up constructively, but it could also add up destructively as well.
  • As one of the commentor was suggesting, the most likely solution would simply be to add a pre-amplifier, as the noise is probably due to low input signal level into the amplifier, where the internal noise of the amplifier is drowning out the microphone signal.
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