High level input vs low level input


CarAudio.com Newbie
Jun 9, 2020
I have a 2012 optima sx turbo with the stock infinity system without navigation and I got two p3 15's with a 3000w pl3000.1d amp and a lc2i loc. My question is why does it seem to only hit when I have it on high input and not low input? Is that how its supposed to be? (Ps. I have the loc running off the factory sub in the back and my subs are wired to 1ohm)


5,000+ posts
10+ year member
Dec 29, 2001
Lawrence, KS
Are you sure it's not the other way around?

When it's set to low - your gain's sensitivity range is 0.1v to 2.0v.
On high it's 2v to 8v.
So if your input signal is 1v, for example (wild guess), and your gain is at ~50% then on low range it SHOULD be set about where you'd expect it to be, and output should be reasonably high.
On high range your relative signal input would be very low (amp would be adjusted for ~5v) so output would be low.
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CarAudio.com Elite
Apr 27, 2020
United States
So long as your LC2i is set up to be near maximized at your system's highest clean volume level then all that matters is that your amp isn't clipping. The bigger the signal the better (so long as it's not clipping), because it will help remove any potential interference. The only time you'll want to turn down the LC2i when it's not maximizing at high volumes is if your amp's lowest gain setting is still too loud. In terms of the "correct setting" for the amp though it's low input. High input is for running direct from speaker wires, not an LOC.

Pretty sure n2audio is right about you having low and high switched.

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