Bass Thump

[monkeyman 10+ year member]

Hey guys i recently bought a Pioneer-DEH-P3900MP and i have came to the conclusion that the HU(s) are crappy for the reason being that everytime i turn on my car ,my subs make a loud thump noise and then delays about 6 seconds for my subs to actually power on to the beat of the music not only that when i turn off my car it makes a super loud thump and its odd because i tried turning down all the bass boost down on my amp and my gains are to a real low level and i still get a pretty loud thump from the sub.Also i have an epicenter which i lowered down alot as in almost off and still get that loud noise... would you guys recommend me to just chuck the HU and go with maybe a Kenwood HU or perhaps a JVC ... and i did try grounding the RCA's but wasnt very succesfull becuase it would always blow my amp fuse.

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[hoxie08 5,000+ posts]

well if your amp is turned down and it still thumps maybe it is your amp?

 

[spoonraker 10+ year member]

The turn-on thump has nothing to do with your HU. Unless your amp has a built in delay, no matter what's hooked to it, you will get a thump when it turns on. This isn't a signal being sent from your head unit it's simply just the amp sending out a little power jolt when it first turns on. The settings on the amp have nothing to do with it either.

It's also normal for an amp to take a few seconds to "warm up" before the bass will kick in, especially on Class-D amps. This, again, has nothing to do with your head unit.

 

[pilyin 10+ year member]

Actually it is possible that the head unit is causing this. Make sure your remote on wire is connected to your remote output on the headunit. You might also try checking your ground on the sub amp and making sure it's attached to bare clean metal.

I would not say it's normal to get a loud thump when you turn on your system.

 

[monkeyman 10+ year member]

well the amp was previously insalled in another car with a SONY HU along with the rest of the stuff so when i trasnferred my system to this car i decided hey those PIONEER HU'S look kinda nice i think im gonna get me one so then i did and then i heard about the RCA issues it has but ever since it came out the box and into my car my sounds started to thump when the car turns on and off.