Tuesday, August 22, 2006 - 04:33 pm, by: James Johnson(Jamesy)
you can buy a little box thingo i cant remember what they are called. you can get them down at autobarn in the audio section. my brother got one and fixed the problem right up in his car!!
Friday, August 25, 2006 - 06:15 am, by: Hayden Miller(Zero)
Are you running an amp, assuming you are the box is a "ground loop isolator" you run your rca's through it before they enter your amp. also check and ensure your power and rca cables are running down seperate sides of the car, and check your earthing, make sure there clean.
engine noise is a huge problem... iv tried everything to get rid of mine, its still there.
Friday, September 08, 2006 - 08:45 pm, by: Peter Bullman(Pete)
Refer to previous posts regarding this as there is a quite extensive answer in there...
I'd first try to get some high quality RCA's.. I recommend Streetwires. If you DO go streetwires, most of them come with a wire running down the middle between the cables.. Earth one end to the same earth as your deck and the other to the earth on the amp.. again, for a technical reason for this refer to a previous post (not too long ago..)
If you can, steer clear of ground loop isolators.. they tend to, not only suppress your wining, but suppress a huge amount of sound!!
Friday, September 08, 2006 - 08:48 pm, by: Peter Bullman(Pete)
Here is the extract from the post I mentioned..
"The whine is a result of the 'potential difference' in the grounds of the differing components in a car.
The chassy is the 'common or ground' (no •••• you all say). When the car is running, the altinator which incidently, runs somewhere in the vacinity of 10 to 11 volts AC (3 phase). With the use of several diodes (electrical 'one-way' gates), a rough DC supply can be obtained. Because no DC supply (with exception of a battery) is perfect, it adds 'noise' into the DC operation of the appliance which in this case is the car and stereo combined.
Alright, so, next... When the car is running, depending on your revs, the true supply voltage can be anywhere between about 13 and 15 volts. I'm not talking fluctuations over a 10, 20 or 30 second period, I'm talking over a .001 or .002 second period. As you accelerate, this fluctuiation time decreases. Revs increase, the speed of the altinator incresese, the generated AC frequency increases hence the fluctuation in the DC increases and the pitch of the whine gets highter because the frequency increases.
Making sense so far?
Now to what causes the 'ground loop'. There are a couple of 'rules' that are in place in electrical circuits. 1, Crrent and voltage are inversly proportional (higher thump from subs = dim in headlights cos current up, voltage down). 2, Voltage is the potential difference between 2 points (so, if you had a 100V dc supply, hooked up 4 25ohm resistors in series and connected them to the positice and negative terminals of the supply, 25v would be getting 'used' or 'dropped' by each resistor)
pos---[25ohm]---[25ohm]---[25ohm]---[25ohm]---neg
Alright, because, after installing extra parts in your stereo and grounding them at different points, the voltage each device is running off slightly differs. Head unit uses bugger all current, so the voltage to is remains relatively constant. Your great big 'mother of god' Class D Mono block feeding 2000wRMS into a 1ohm load is going full out scaring little kids and parting vain womens legs at 500metres. The voltage drop is in full sway as a result of your leg parting and kid crying amp/sub setup. The negative does not always stay at 0 and the positive not always 'pulls' down to the ground.
This means that the head unit may be running off 13.3v. the ground a +0.8v and the positive at +14.2v.
With amps grounded at different point, they do what's technically called by those in the loop as 'weird ••••••
Big bass, big current, big voltage drop. That same 2000wRMS amp may very well drop the voltage between it's ground and positive terminals to around 10 or 11v - maybe even lower. I know that with my last car, a big Big BIG bass hit would stall the engine at a set of lights.
This is what causes a potential voltage difference in the ground points of the stereo. That is why, no matter what, do everything and anything to ground all parts of you stereo in ONE place.
Running an extra ground wire from the head unit to the grounding point in the boot results in a 'short circuit' between these two points, so, the voltage difference between front and rear grounds is eliminated.
Hope this has shed some light - in some way. It is very had to explainin a way that is easily understood on a forum. To really allow people to understand how and why it is caused and how and why it is stopped would take a whiteboard, an array of different coloured markers and a dirty schoolgirl with pink panties and a short skirt sitting in the front row. Damn me and my fumbelling fingers - always dropping ny pens..."
Hope this helps..
p.s. I needed a two-hour sleep to recover from reading that!!
Geordie Smith Tinkerer NSW 2x V8 GT Soarers His & Hers, awww
Sunday, November 05, 2006 - 11:12 am, by: Geordie Smith(Big_george)
I had a problem with noise coming thru my amp.
I tried all them doohickeys from jaycar to smooth it out and what not, just lost volume and quality with those.
In the end, I made up a loop wire off my RCA plugs and put a ring on it, bolted it to the passenger seat on the floor to earth out the shielding of the RCA plug and amp.
Typically on car audio the outer shield of RCA plug is unused, and the tip or inner wire is the signal. Earth the ring of the RCA or the outer shielding of the wire, to the body of the car.
The noise was instantly gone and the amp was working perfectly.
Wednesday, June 24, 2009 - 10:25 am, by: Nathan Sheehan(Soarermad1)
Best method is to upgrade your earthing wire to something thicker as you are bottlenecking the amount of power feed out of your amplifier causing it to create noise from the alternator.
Because power flows like a river, if the amount of power going into the amp can't filter out the other end it will 'flood' the amp and leave a nasty signal (the sound you hear as your alternator increases amperage as you increase RPM) as the voltage may increase for a short period (at the amp, not battery) to 14.4v on high RPM and drop back down to 12.8v or less on idle
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