i need help with a noise problem

i have a few questions about a noise problem with a install. i am mecp certified and have been in the industry for about 9 years. but i have a problem that i cant seem to find a answer for. i have a rockford fosgate 800@2 in a install that is runing a set for hifonics components and it has alternator wine in those speakers. the noise is there even when the signal cables are unpluged. i have changed the ground many times and relocated the amp away the big power cables. please help if you can. you can call me if you want or i will call you 706-333-7865 my name is gene.  

amp mounted to amprack mdf. yess all new speaker wires.

the vehicle is a grand prix about 98 year model. and i have checked the gains.

IMO the problem is the amp you are using, rockford is great for bass but for mids and highs they suck. At any rate there is probably something going bad in the amp causing the engine noise, since you said it is still there when the rca's are unplugged this is probably the problem. Certified Security Specialist

Always check info with a digital multimeter.

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Check the ground for the battery to the car's chassis. They are usually in need of a good cleaning to remove rust and corrosion. Make sure your amp's power cable is securely fastened to the battery with heavy gauge cable. Make the ground cable as short as possible and to a clean, paint free part of the car's body. Hook up test speakers next to the amp to determine if the noise is coming through the speaker wires.sparky

You may want to do a simple test on the vehicles alternator to eliminate that as the cause.If only one of the diode packs are faulty / shorted. It will emmit RFI / EMI into the vehicles electrical system.The old tech method of doing this without a scope, or a DMM that can capture the AC output.Simply take a florecent lamp, unplugged. Wave it over the engine compartment, and see if the bulbs come on slightly.You will of course have to turn off all the lights in the shop, as the emmitted light output is rather low.The wand method works in a pinch for those not having the equipement to do a diode check on the alternator.Even if the noise does not flucuate with engine RPM, does not eliminate the alternator as being the culprit, as some vehicles are able to produce a fairly steady DC output with 2 diode packs semi-blown.Just a thought.RegardsEVIL Teken . . .

Make sure the crossovers from the components are not mounted near any power wires or computers, found that one out by accident, still sounds like an amp issue though.Top Secret, I can tell you but then my wife will kill me.

Maybe try a line driver?Gary Kline

MECP Master Technician