I have a device in my car thats wired and it says
freqency and rev and normal and has a button to
it,dont know what it is
I believe that has to do with the audio.
I dont know,why does it say rev?
Yes, that device is like what controls the audio. "Rev" stands for reverse, it is in every car. What "rev" does is that it flips the polarity (-/+) of the Sub relative to the rest of your speakers. This essentially puts the sub 180 degrees out of phase.
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