# Rockford Fosgate P400-4 Question



## BigEvil2005 (Apr 23, 2009)

I have a P400-4 and its putting alternator whine through the speakers and I know what your thinking grounding issue or bad RCA cord but I dont think it is. I put it in all 3 of my cars and use a 4GA ground less that 12" and bolted to the chassis. My Kenwood works great My Hifonics works great in my other cars the Rockford is driving me crazy. I tried the filters and at this point I believe its the amp so I did Rockford's test to hooked an Ipod direct to the amp and the whine is there. is there a way to fix it?


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## hondaman916 (Apr 28, 2009)

Try this Car Audio - diyAudio

A lot of people are helpful.


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## S10Okie25 (Jun 18, 2010)

I had the same problem with mine after I first hooked it up. A few weeks later i changed the ground location and the whine disappeared. Recently installed the miniDSP and changed the amp around and now it's back. Have yet to see whether it's caused by the DSP or not, but I would check the ground, as that's the only thing I changed in my setup...


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