QUOTE]I think I understand ur drawing, I connect the two blue circles. But how would i adjust these setting? I think it should be : filter-lpf, operation-stereo, input selector-A only,and input sensitivity would just depends on how loud i want it.
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using Input A, set the amp to do LPF or low pass filter. the amp will run in a Mono channel meaning it will push the sub ONLY.
now settings gains is really simple. donwload a 50hz 0db sound track. play the song, but turn off all eq, loudness etc on your deck. turn it loud to th epoint where your speakers start to crackle. if they crackle at that point (known as clipping) turn it down a few notches. dissconnect your sub(s), place your DMM (digital volt meter) and place Red on (+) speaker terminal and Black on (-) speaker terminal. Using the gain, turn it up, so you get a reading in DC (set dmm to 100v DC). the number you get will correspond to the output of that connection is RMS. example, your DMM shows 40.0volts. that means your amp under clipping will be sending out 400watts RMS. adjust accordingly. dont be too cocky and if your subs can take 300watts dont set the amp to 400w. your just risking or fryin ut sub and possibly amp.