humming in subs...

allstar0087 · 03-08-2007, 04:39 PM

Hey guys, i've been lurking the board for about a week or so (looking into carPC's). I've recently ran across a problem, and i hope you guys can help me. I have 2 alpine type R's connected to a hifonics 1200watt amp. As of about a few days ago, I started getting a humming in my subs.

It's hard to explain, but when there's no sound on and the amp is set at a low level, the subs vibrate for no reason. If i turn up the amp a bit, this vibration turns into an all-out distorted banging from the subs. I'm not sure what the problem is, it only started a few days ago.

I re-wired everything, just to make sure the wiring was good (including the ground). I also ran and tested a different set of RCA cables. I ran these right down the middle of my car as far away from the power cable as possible. So i dont think the power cable is causing interference.

Do you guys have any other suggestions. I think I may have a bad amp, something possibly wrong with the RCA inputs (doesnt make the sound if i take the RCA's out). What do you guys think?

Thanks, sorry for the long post

boomintrac · 03-08-2007, 10:22 PM

Are you running a headunit or aftermarket converter from the factory radio? I know you checked your ground but where do you have it secured and length approx? How high are the gains on your amp?
Aron

allstar0087 · 03-09-2007, 02:35 AM

i'm running an alpine aftermarket head unit... the ground is approximately 2 feet, maybe 2.5 feet, and it's bolted right into the body (all paint removed, and a solid connection). even with my gains low, it still has a little interference, but obviously not as much. The thing is, i just had somebody hit me from behind, and it started happening after that (i had no problems before that, with the same ground location). i had my amp between my sub boxes, and something might have gotten pushed the wrong way. I'm out of options at this point.

durwood · 03-09-2007, 07:49 AM

Is the amp screwed directly to metal? Some amps do not like to have the chassis screwed to metal. Another thing to try is plug an MP3 player or other portable audio device and see if the noise is still there. If it goes away then you have a ground loop somewhere. Check the ground on your headunit.

allstar0087 · 03-09-2007, 09:41 AM

my amp is screwed into the top of my sub box, so that's not the problem... I'll try hooking up my ipod and see where that gets me. thanks

supraman22 · 03-11-2007, 10:22 PM

i had the same problem. even when i turned my volume all the way down they still hummed, when i hit a button on the dash the subs hit, etc etc. Turns out the pre outs on my cd player were bad. Got a new one and it fixed the problem. It's funny cause i was in and out of best buy a couple times, those people have no clue whats going on. Hope you get it fixed.

allstar0087 · 03-12-2007, 12:06 AM

hmmm... didnt even think about the pre-outs on the head unit. i really hope that's not the case lol

boomintrac · 03-12-2007, 11:44 AM

with the rcas attached to the amp try to wiggle the connection it could also be the input on the amp, if during the accident something could have hit the rcas and pushed them into the amp making the inputs break a solid connection putting that at fault.
Aron

allstar0087 · 03-12-2007, 03:14 PM

Quote: Originally Posted by boomintrac

with the rcas attached to the amp try to wiggle the connection it could also be the input on the amp, if during the accident something could have hit the rcas and pushed them into the amp making the inputs break a solid connection putting that at fault.
Aron

that's what i'm pretty sure it is. When i wiggle the connections on the amp, the humming basically stops when i push it in a certain direction, and you're probably right, i think it happened in the accident. I sent hifonics an email last week regarding the situation, but havent heard back from them. anybody have success with their customer service?

boomintrac · 03-12-2007, 10:48 PM

If you want a faster responce I would hit them on the phone. Here is their number 847-540-7700, The email most likely will not get a responce for 2-5 days
Aron

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