Did you already override the head unit EQ in Forscan to try and get a “flat” signal out of it?Here's the problem as many already know... the rolloff of all the speakers is bad and the sub just doesn't see the full low range it needs. We can get a lot of mid-bass but not low bass. Nothing we can do on the head unit "eq" nor the gain on the sub can fix bad signal from the source. UNLESS we add a line-output converter that corrects for rolloff!
I don’t know if that will help get you enough signal voltage for your amp, but I would recommend that tweak before depending on DSP to put back what the head unit is intentionally taking away.
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