noise in my system

[SCStreetRacer]

i just finished wiring my dad's car (95 SHO) with a separate amp for speakers, and subwoofer......for the speakers i used a Boss Riot 1000W peak (100x4 RMS) amp....i used the factory wiring that went from the factory amp in the back. and i used a sony 400W for his JL 8in........is sounded great until i started the engine. I heard a buzz/hum/high pitched annoying ass sound that gets higher and lower with engine speed. I rechecked all of my grounds.....sanded the points and changed locations......but it's still there......i even pulled out the HU and grounded that again........I used a 4gauge from the battery and used a splitter to 2 8gauge wires to power each amp.....also i used 8 gauge wire to ground....i just don't get it.......what could be the problem?

[strodda]

damn i had the exact same problem, still dont know what it was. i took it to a shop and they said it was because of a shitty receiver(aiwa) and something having to do with its rca outs. i even rewired my entire car, took out the seats, carpet, EVERYTHING. wired the power and rca down opposite sides of the car, and still the same shit. i think it even got worse. so i ended up putting in some noise reducer and adjusting the eq and gains, and now i cant hear it.
but i would still love to fix it the right way... whatever that is.

[SCStreetRacer]

where do i get one of these noise reducers?.....will it affect the sound quality at all?

i was thinking of taking it to a place up the road that does car stereos.....but they're shady, and they would probably just install a noise reducer and charge me like 150 bucks......anyways.....thanks

[ci5ic]

Make sure you're running the wires right...

Don't run your power/ground wires right next to the signal wires. Any kind of engine noise from the alternator or whatever will be induced into the signal wires. So, run your signal wires down one side of the car, and the power/ground wires down the other side, as far apart as possible. If these wires have to cross each other, do it at a right angle so that the power wires are perpindicular to the signal wires. This way, it reduces considderably the amount of noise that will be induced into the signal lines...

Hope that helps...

[SCStreetRacer]

they are on opposite sides....dang man.....WTF!!! I'm about to just try one of those noise filters.....will it affect my sound quality in any way?

[strodda]

yea it will a little, but i didnt really notice a difference. although dont be too picky about sq seeing as how anything is better than a loud humm.

ci5ic-thats exactly what i did. could there be any other reasons? is it possible its just a shitty receiver, or it has bad rca outs.?

[PaulD]

well, I see the voodoo troubleshooting is still alive and kicking ....... running the power and RCA's on different sides will NOT alleviate this problem. If it were true, and the noise is coming from the power wire, then there would be no noise when the volume is turned all the way down, since there is virtually no power coming thru the power wire in that situation. By the way, even the MECP people have seen the light - that change will be made to their manuals in the next run - if hasn't been made already.

The guy at the shop may be half right, the problem is almost assuredly being picked up by the RCA cables - moving them to another location may help. Also, the deck most likely has a low output level - causing you to turn up the gains on the amps. Try turning the gains on the amp all the way down. A set of UTP (unsheilded twisted pair) RCA cables will probably solve your problems, along with setting the amp gains correctly.

The "noise eliminator" box is in fact a line level transfomer. Since the signal is passed thru the magnetic field instead of by direct connection, it breaks the physical signal path. It often fixes a number of "whiney" stereos. The draw back is that if it is not a very good transformer (expensive), it can cause a roll-off in the bass almost like a crossover. The other thing is that a cheap transformer can have a lot of distortion from hysteresis, causing a smeared sound. Your best bet is to solve the noise problem at the source, rather than to use band-aid fixes.

[strodda]

damn pauld, thanks for the schooling. couple q's though.

i guess ill look into the utp cables. but for now, where else could i move the rca?? i dont have alot of room to work with. i just have it going straight back from the receiver, under the seats, up to the amps on the back seat. and also, are using utp's a proven result or just a possibility? i dont really wanna spend money on a shot in the dark.

and about the line level, i tried putting the gains all the way down, and that didnt help. what i had to do was put the leveler up, and the gains about half way. i dont hear the humming anymore, but im still sure sq is being messed with.

[strodda]

is this it?? it doesnt say unshielded though.
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1373791057

[PaulD]

Originally posted by strodda
is this it?? it doesnt say unshielded though.
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1373791057

NO .... copper braiding = shileded

UTP's are the the cheapest of cables they sell - you can make them out of CAT 5 cable, or even make them yourself. A good pair of UTP's has been shown to get rid of noise that nothing else could. Moving the cables you have may move them far enough away from the noise source to prevent the hum. HINT --- it may be picking it up in the dash area too.

[strodda]

well damn, im not sure what to do now. i couldnt find anything on ebay, so i was randomly searching and i found this site
http://www.installer.com/tech/cat5.html
pretty much saying cat5/utp cables are bad, even worse than a cheap set of rca's.

[SCStreetRacer]

so you're telling me that a set of unshielded RCA cables is what i need.....as opposed to shielded.........it seems like shielded, being shielded would block interference. The one's i used came with the 1000W Scosche (EFX) wiring kit that i bought from Walmart.......could this have anything to do with it? thanks

[strodda]

i dont think that would matter. the brand is fine, its just that walmart happens to sell it. its not a walmart brand or anything. btw, thats what i have, got it from crutchfield though

[SCStreetRacer]

so are the Scosche cables UTP's? if they are not where can i get a good set? Or should i just make some out of some good speaker wire? thanks

[PaulD]

strodda ..... why does that web site keep coming up ? Eddie Runner was banned from the car sound forum for basically being an idiot. Do a search on it in this forum - I already did a good explanation on why his test was worthless. The "sheilding" IS effective, for frequencies over like 1 MHz (1,000,000 Hz) ..... unfortunatley, AUDIO frequencies are in the 20-20,000 Hz range - and engine noise is typically around 3,000 Hz.

Brand name does NOT matter ... they just often look better. You can make them yourself if you are pretty good with your hands - if you are interested, I can explain it for you.

First off, for those with people that have engine noise in their stereos - you need to find where it is entering. Make a pair of shorting plugs - do this by getting a pair of RCA plugs and soldering the ground pin to the center to pin. Start from the source and work back. Unplug the RCA's from the mid/tweeter amp and install the shorting plugs, turn on the car and see if the noise is still there, if it is YOUR AMP IS THE PROBLEM. Most likely, it will not ..... keep doing this until the noise comes back. If it comes back when you plug the in say the EQ, it could be the EQ or the RCA between the EQ and the next component. This will narrow your problems down logically, and keep you from needlessly replacing wires or componenets.