11. What happens if I apply reverse polarity to acoustic products?
(1) Buzzers
For piezo transducers reverse polarity has no effect; for piezo indicators they won’t function and are susceptible to burnt circuits; for magnetic transducers reverse polarity decrease SPL by several dBs; for magnetic indicators they won’t function and are susceptible to burnt circuit.
(2) Micro-speakers
For single micro-speakers reverse polarity has no effect; for micro-speaker arrays such as dual speakers, if one of the two speakers are applied opposite polarity, sound waves from two sources might cancel out each other due to interference. It may result in SPL decrease, especially in low frequency bandwidth.
(3) Microphones
For Electret-Condenser Microphones (ECMs), reverse polarity might render sensitivity plunging by dozens of units due to inactive FET. MEMS mics might suffer the same problem but their SMT assembly process reduces possibilities of erroneous polarity.
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