Static when I hit a bump

[aclarson]

Hello, I have a question regarding some static I get when I hit bumps in the road. I just got a new Alpine MRP-F450 amplifier that I'm using to drive 2 Infinity Kappa 5 1/4"s' w/tweeters (fronts) and 2 Infinity Kappa 6 1/2's (rears). I haven't tweaked my gains or my crossover or anything yet, the gain is set at about half, I just tried running it to see if it works. I have 4 gauge wire coming into my power and ground distribution blocks running 8 gauge wires out to the amps with spade lugs crimped on to clean it up. I'll be installing a sub amp and sub tonight, but haven't hooked them up yet. Anyway, the fronts and rears sound fine when I'm parked and most of the time when I'm driving, but sometimes when I hit a hard bump, I hear a crackling static sound come from all four speakers. Is this something loose in my amp, or does this sound like an issue someone else has had before? Thanks for any help you can provide.

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[headless 10+ year member]

Hello, I have a question regarding some static I get when I hit bumps in the road. I just got a new Alpine MRP-F450 amplifier that I'm using to drive 2 Infinity Kappa 5 1/4"s' w/tweeters (fronts) and 2 Infinity Kappa 6 1/2's (rears). I haven't tweaked my gains or my crossover or anything yet, the gain is set at about half, I just tried running it to see if it works. I have 4 gauge wire coming into my power and ground distribution blocks running 8 gauge wires out to the amps with spade lugs crimped on to clean it up. I'll be installing a sub amp and sub tonight, but haven't hooked them up yet. Anyway, the fronts and rears sound fine when I'm parked and most of the time when I'm driving, but sometimes when I hit a hard bump, I hear a crackling static sound come from all four speakers. Is this something loose in my amp, or does this sound like an issue someone else has had before? Thanks for any help you can provide.

My first guess is a bad ground..where did you ground? check to make sure it's tight and to a clean metal surface.

 

[aclarson]

Thanks for the reply. The 4 gauge ground wire was already in the car when I bought it, so I'm not actually sure where it's attached to, but I did verify it with a multimeter. The wire disappears under the rear seat, so I'm assuming it's attached to the floor plate. I had another amp in there previously, but it was stolen, so I bought the new Alpine to replace it. I'll check it when I get home later, but I would assume the ground is solid since it worked fine on my old amp.

 

[aclarson]

Sorry for the double post. Another thing I just realized is that when I turn down the volume on the head unit, I don't hear the noise. It is proportional to the volume level of the head unit. But I've had this HU for 3 years (it came in the car). Hmm....

I did have the HU out the other day to trace some wires and noticed that whoever wired the thing did kind of a crappy job, there were some wires just twisted together and wrapped with electrical tape, maybe it's one of these wires jostling loose when I hit bumps.

 

[johnecon2001 5,000+ posts]

Try to rewire that HU if you can. You should also check the integrity of the RCA's. Static is usually signal related. Whine and hum is usually ground related.