I just installed a MB Quart sub and a Lightning Audio 200w amp and I get severe engine noise in the Sub. I ran the rear speaker wires to the amp (it has high level speaker inputs) and the power wire runs from the battery, through the inside of the fender and then into the cab through a grommet. Then it goes along the sill panel to the amp behind the seat. The ground wire is about 12" long and is grounded to one of the bolts that used to hold the storage box in. I sanded it down to bare metal and the amp and speaker will work, but with VERY loud engine noise coming from it. This setup is in a 2001 Lightning if it makes any difference. I do know for a fact that the speaker wires from the factory are hooked up to the amp correctly.

Thanks for any and all help,
Roger

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The early bird gets the worm, but the 2nd mouse gets the cheese.

2001 Black Lightning
Stock, but not for long...
Best Stats:
RT .519
60' 1.986
1/4 13.73
MPH 99.83

1996 White Mustang Cobra
Offroad H-Pipe, MAC Mufflers, and a K&N

,
This PIC provided so that Chevy
and Dodge owners can see what
the front of a Lightning looks like.

My First Attempt At A Web Page
Roger's Lightning Page

 

Hi Roger,

I am no audio expert by any means,
but I have had my share of it in the past
5 yrs or so...
And from what I have seen, the ground wire is
usually the cause for this. Even though sometimes you ground looks good, it isn't.
I'd run another wire from your ground to another location just to see if that corrects your problem.
If not then I'd try an audio filter hooked up to the spkr wire itself. These are usually
not more that 10$.

Good luck..

Morley

 

It is very unusal to have engine noise in a sub. This is because the "whine" which is usually from the alternator is at a much higher level than what a sub is reproducing. Are you using a crossover at the amp? If not, try setting the one on the amp to about80Hz or so. Also make sure you power wire stays away from the computer. Computers can generate quite a bit of noise and your power wire can be picking that up.

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97 F-150XL 4.2V6, 5 spd, 2wdlb, Kenwood cd, MTX 4ch amp, MTX 12"sub, MTX components in doors

Future 16x8 Daytona wheels, 265/75 tires, rhinoliner, perf stuff

 

Thanks for the help guys. I think I'm going to try to ground problem first, since the sub seems to be underpowered also. But, the power does get pretty close to the computer too, so I'll have to try something there too. The noise that the sub is making sounds almost like the exhaust! At higher RPM's it pretty much goes away (still a very small amount of noise though). Thanks again.

Later,
Roger

 

Also try seperating the RCA cables to the amp from the power line. You could be picking up the noise through their. Also disconnect the RCA from the amp, if the noise goes away then it is further up in the system. If it says then it is the amp itself. You can also try grounding the outer conductor on the rca cable. Sometimes their is a poor ground. If this works, solder a wires to the cable and ground it to the chassis.

 

Hey Cobra,

I have seen this a couple of times, and a fix might be to take those rear speaker wires, run them through a high quality line out converter, and then use the RCA inputs on the amplifer. 9 times out of 10, the high level speaker inputs to those amps are junk. One of those audiolink converters could be your best bet. I doubt that having the speaker wires too close to power wires would make that buzzing as loud as you say it is, since the signals are at a much higher level. Usually you only have to worry about power wires being too close to RCA (line-level) wiring, since those are relatively small signals. But who knows, theres always a first for everything. Let us know what the fix is!

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2001 F150 SC Red XLT
4x4 Off Road Package
5.4L V.8 3.55LS
Go-Rhino Grill Guard w/KC o-r lights
Pioneer Premier DEH-P410
A/D/S/ 236is front spks
Alpine SWR1040 Subwoofer
Rockford Fosgate 500.2 & 400.4 Amps
Viper alarm w/autostarter

 

JBirdZ,
You were right! I had bought a Rockford Fosgate converter, but decide I would just use the high level inputs on the amp. As soon as I put the converter inline everything was fine! I also installd a ground loop isolater for good measure. Now all I need to do is put some polyfil in the box for a little better sound since my box is .8 cf and I need 1 cf or a little more.
Thanks for all of the help/suggestions guys.

Later,
Roger

------------------
The early bird gets the worm, but the 2nd mouse gets the cheese.

2001 Black Lightning
Stock, but not for long...
Best Stats:
RT .519
60' 1.986
1/4 13.73
MPH 99.83

1996 White Mustang Cobra
Offroad H-Pipe, MAC Mufflers, and a K&N

,
This PIC provided so that Chevy
and Dodge owners can see what
the front of a Lightning looks like.

My First Attempt At A Web Page
Roger's Lightning Page