Subs making random thumps when HU is on.

[yarn]

Setup:

• Pyramid amp,
  
• 2 Alpine subs
  
• Cheapest alpine deck I could find.
  

After driving for a few minutes, the thump starts to happen. Also when it happens, I can hear a high pitch spinning when I rev tthe engine. They both happen simultaneously. But at very random times. It'll thump for 10 - 60 seconds, then stop for a few minutes.

I've never experiened this until I moved the ground for the amp. I moved it back to the original spot (when there were no problems.) but the thumping/engine humming persisted, so I sanded down the metal grounding the amp. (That didn't really solve much, it alleviated the problem though. Which doesn't make sense to me, because it was fine when I first installed it. It worked fine up until I decided to play with the ground)

The thumping/engine humming stops when I shut off the HU.

If it's worth mentioning, when I moved the amp ground, it apparently wasn't good enough (and caused the amp to heat up pretty quick. I started hearing thumping noises 5 minutes into driving, as soon as I heard it, I pulled over and swapped the ground to where it original was. Also... when I was messing with the wires, I had one sub in (+)(-) and the other in (-)(+) which canceled each other out. I didn't realize this until 20 minutes into driving.

Did I mess up bad? Do I need to ground the head unit? Do I need a new amp?

Click to read more...

 

[Chris Z 10+ year member]

Hmm. I don't think you screwed any of your electronics up. Try grounding your hu though, that might be it. Other than that though, I think you might just need to get a higher quality amp.

 

[yarn]

Chris Z,

I'll try grounding the HU tmr, when stores open, so I can buy wires. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Okay, I've done a few trial runs. I get thumping/engine noise when the RCA's is connected.

The thumping/engine noise stops when the RCA's aren't connected. What does this mean?

Btw. This doesn't make sense, why did the thumping/engine noises only start after I played with the amp ground?

Any other solutions? I'll ground the HU when I can get wires for it. Perhaps my gain is set too high?

 

[Chris Z 10+ year member]

Yeah, try turning your gain(s) down and see if that decreases the intensity of the thumping sound. If it's still the same, I would definitely try grounding the whole hu and/or the RCAs on the HU.