Sub very loud at startup

[Cat K20]

I've searched to find a solution for a few days now, but have come to no success.

I wired my sub and amp following a guide on here and was able to make it work... With some issues.
On startup, the sub will blare unless the RCA cable is unplugged and plugged back into the amplifier. Recently, it won't make any sounds at all. However, after plugging the RCA in and out, it will work perfectly!
Has anyone else ever run into this issue?

S-line A4 2WD with Audi Symphony

[Noel Artiles]

I've searched to find a solution for a few days now, but have come to no success.

I wired my sub and amp following a guide on here and was able to make it work... With some issues.
On startup, the sub will blare unless the RCA cable is unplugged and plugged back into the amplifier. Recently, it won't make any sounds at all. However, after plugging the RCA in and out, it will work perfectly!
Has anyone else ever run into this issue?

S-line A4 2WD with Audi Symphony

Your + & - is crossed most likely. It happened to me as well when I used a cable that was hard to read which was which. Go back, follow your speaker wires and make sure + runs to + and - runs to - from amp to sub.

[Cat K20]

Your + & - is crossed most likely. It happened to me as well when I used a cable that was hard to read which was which. Go back, follow your speaker wires and make sure + runs to + and - runs to - from amp to sub.

Will do! I'll post results after I do that. Thank you!