Subwoofer issue...

[agart]

So I've replaced all the stock stereo components with aftermarket ones(see sig) and I've been having an issue with one of my subs. From the moment the amp turns on there is a constant humming noise. It doesn't vary with volume but when I touch anything on the screen it'll make a thump that goes with the touching. I've checked grounds and such over and over again and have found nothing. It plays just as loud as my other sub which does not make the humming noise. I did a quick google search and some people were saying its a bad cap... Does anyone have any other suggestions/has this happened to anyone else and what did you do?

[IronAudi]

sounds like a grounding issue, or there isnt enough power. Its been a while since ive installed my system. I havent done it in the Audi yet cause i dont do good work just ok werk.

[05A$SE]

i know this sounds stupid but i had a x subwoofer and if i remember they were a pain to wire up. maybe you have one wired wrong and the other correctly? i would just double check how the 4 posts are wired on the back of the sub.

[agart]

sounds like a grounding issue, or there isnt enough power. Its been a while since ive installed my system. I havent done it in the Audi yet cause i dont do good work just ok werk.

I've checked the grounds soo many times, I actually pulled the wires and rewired it to make sure. That and I pulled the ground off and resanded all contact points to make sure there was no paint in the way. I would agree with the power issue but when I crank it, it still hits hard.

[agart]

i know this sounds stupid but i had a x subwoofer and if i remember they were a pain to wire up. maybe you have one wired wrong and the other correctly? i would just double check how the 4 posts are wired on the back of the sub.

Yea wouldn't hurt to look those over, thanks.

[ScaryGary]

you should never have multiple grounds in an aftermarket stereo system. Your grounds need to be tied to one point via a distribution block. I've done some competition grade stereo work and found that grounds will make or break your system. They are just important to consider as the equipment you buy.

If you are running a capacitor, all amps need to be grounded to the capacitor, and the capacitor then grounded to the chassis.

Also, make sure that you are running a sub that has the correct impedance for the amp you are powering it with.

Good luck

[kwik_shift]

Wouldn't hurt to check the rca cables. I remember in my C5 if I would have the amp on park, turn the igntion off and all of a sudden a loud humming noise. Turned out to be bad rca cables.

[pa4ul]

question i always wanted answered can u ground ur amp to ur cap and then ur cap to chassi? will they help sound at all or just less power cosumsption? Im going to rewire tonight. I had the idea of doing that but didnt want to fry my amp with bad wiring. And the humming noise make sure ur rcas arent running near ur fuel pump that might cause the noise or some interference in the engine compartment. Check rcas and make ur grounds as short as possible.

[agart]

you should never have multiple grounds in an aftermarket stereo system. Your grounds need to be tied to one point via a distribution block. I've done some competition grade stereo work and found that grounds will make or break your system. They are just important to consider as the equipment you buy.

If you are running a capacitor, all amps need to be grounded to the capacitor, and the capacitor then grounded to the chassis.

Also, make sure that you are running a sub that has the correct impedance for the amp you are powering it with.

Good luck

Yea thats how I have it set up. All amps are connected to a block which connects to the cap and then is grounded. My multiple grounds I meant the headunit connections as well as the cap, sorry if that wasn't clear. As for impedance the subs are each dual 4-ohm connected to a 2-ohm stable amp. Assuming I have wired them right, which I'm almost 100% each sub should should be at 2-ohms.

[agart]

Wouldn't hurt to check the rca cables. I remember in my C5 if I would have the amp on park, turn the igntion off and all of a sudden a loud humming noise. Turned out to be bad rca cables.

True, now that I think of it one set of my RCA's was a spare set I had laying around home... Thanks

[agart]

question i always wanted answered can u ground ur amp to ur cap and then ur cap to chassi? will they help sound at all or just less power cosumsption? Im going to rewire tonight. I had the idea of doing that but didnt want to fry my amp with bad wiring. And the humming noise make sure ur rcas arent running near ur fuel pump that might cause the noise or some interference in the engine compartment. Check rcas and make ur grounds as short as possible.

Didn't even think of the fuel pump... good call. As far as wiring, it's actually recommended that you have them all connected to one common ground and then to chassis. I think its the same power consumption and no increase in sound but it helps in eliminating unwanted stray signals.

[pa4ul]

yea i had that problem where i kept getting a whining noise and i rewired my entire setup and still whine. I moved my amp and rcas away from the little fueldoor underneath the carpet and sound gone! i recently purchased a hifonics amp and was wonderin what sub to run to it. college budget!

[Turbo1A4]

pa4ul where at in corpus are you located...just wondering cuz i do work out in ingleside navy base alot and i am about to go out there for like 6 months

[pa4ul]

kings crossing area i thought they shut ingleside down? lemme know when u come down love to chitchat audi

[ScaryGary]

good call on the fuel pump.... I've always ran power wires from the battery to the trunk on the fuel pump side, and the RCAs on the opposite side.

however, now I run all balanced audio cables FTW! (denon, zapco, soundstream)

[ScaryGary]

the reason for combining grounds is to eliminate ground loops. If you have grounds in separate places throughout your car, however everything is being powered by the same 12+, you can create differences in voltage potential in the chassis, which the amps really hate, and cause noise, clipping, etc...

[PCYC]

Scary Gary your a badass, All of what he is saying is very true, Good wiring is just as important as the system

[ScaryGary]

I went to school for electrical technology and did a lot of private install work. It's been fun!