| wally91chevrole |
Aight yall. Heres my prob. I've got a 91 Silverado and I have BAD engine noise on my subs and my tweeters. I have an Audiobahn A8000T amp hooked up to my subs and an Audiobahn A6004T 4 channel amp on 4 tweeters. I regrounded all my grounds in new places and was SURE to make a solid connection. I also purchased some Rockford Fosgate dual twist signal cables for both amps. I thought for sure this would eliminate the engine noise. But its still there. Before I start the truck up, everything is chrystal clear. When I start the truck the subs rumble really low and the tweeters make a high pich buzz noise. Ive tried messing with all my settings and nothing changes it. Adjusting the level only makes it louder or softer. What can I get to eliminate this engine noise or what can I do? I've got my power wire that runs from my battery, through the firewall, down the passengers side of my truck back to my amps. The wire is 4GA from the battery to a splitter in the truck and then the wires split to two 8GA wires. One of those runs directly to my A6004T amp and the other runs to an Audiobahn capacitor and my A8000T amp. Each ground is in a separate place on the frame of the truck and are 8 GA wires. My signal cables are only 6.6ft and run from my CD player down the middle of the truck to the amps. The CD player is a Pioneer DEH-P9600MP and is only 6 months old. I may also point out that before I had the A6004T amp, I had a Sony 4 channel amp and there was LITTLE engine noise. None on the subs. Now that I put in this new amp, Its gotten way worse. All help is appreciated.
This is what I've done to try and diagnose the problem:
-Unhooked the signal cables from amp (noise stops)
-Unhooked signal cables from headunit (noise stops)
So now I KNOW my signal cables aren't picking up the noise and my amps are fine because the noise stops when no signal cables are connected
-Tried all steps found at http://www.crutchfieldadvisor.com/I...rint=1&page=all
- I have not yet purchased a noise suppressor because I wanted other opinions. Acording to what crutchfield says, I need a noise suppressor to hook up to my power wires of my head unit (power line noise suppressor). Will this help? I've read a few bad things about Pioneer head units having bad engine noise problems (not very happy about that) through the pre amp outputs... If i KNEW the suppressor would help i would buy one because i really like my CD player.
What are your opinions? |
|
|
| Perry Babin |
| Many times, when installing a new amp, people allow the RCA shield to come in contact with a live power wire. If this happens, it generally burns a shield ground trace in the head unit. To check for an open shield, set your ohm meter to ohms or diode check, unplug all RCA cables from the head unit and check for continuity from the case of the head unit to the output shield. It should should read ~0 ohms (~0 volts on diode check). If it reads as open, the shield ground is likely burned. A temporary grounding of the shield to the case of the radio can confirm that this is indeed your problem. If the noise goes away with the temporarily grounded shield, the head unit needs to be repaired. |
|
|
| dhaen |
| You may have ground loop problems. These can be fixed by fitting audio isolation transformers in the signal leads. Have a look here for more details. |
|
|
| boxcustom |
| you can put a large computer cap right on the alternator positive and ground. this will reduce any noise coming from the charging system. This is probably not the problem, but change your amps. audiobahn invests a large amount of money on the outside of their amps, not on the inside. |
|
|
| sdoom |
Hi
usually noise that changes frequency with engine RPMs is a GND-loop problem, but it it is sometimes generated by input impedance of the amps , that might be the reason why the noise is louder with the audiobahn amp than with the old amp. I would try to get rid of the noise without using the in line transformers, I would use those transformers only if all other possibilites fail.
One thing that really affect GND is your big capacitor. Make sure that the cap is not connected to the carīs chassis . (BTW: the cap is not doing what it is supposed to when connected to the carīs chassis or when the wires running to the cap are longer than 10 inches) . Place the capacitor as near as possible to the amp that drives the woofer and connect the cap-wires directly to the power-terminals of your subwoofer-amp.
As "boxcustom" mentioned audiobahn is not a high-end product. I assume itīs closer to a korean standard amplifier. Those units usually use a very small wire to "shield" or better said ground the amplifier chassis (this wire is inside the amplifier) . Sometimes this causes problems, when the amplifiers are mounted where the amplifier mounting screws are directly touching the carīs chassis. Try to unmount the amplifers and make sure that the ampolifierīs case are completely isolated from the car chassis. If that eliminates the noise you can use a piece of wood , screw down the wood to the car and mount the amp on the wooden surface.
Depending on your amplifiers inside it could also be another problem. Some manufacturers connect the music-signal GND (meaning the RCA-shilding) to chassis GND (e.g. older Philips car amplifiers). If so your car stereo (=head unit) may have really problems and also might already be damaged like "Perry Babin" mentioned.
Also sometimes the noise goes away when a big GND-wire is attached to the amplifierīs housing. You should also consider running complete new power-wires to your car stereo.
Another thing you can try is to use a different GND- point for your amplifiers. You should connect both amplifier GND-wires to one point at your car chassis. Usually good points are the buckle-screws as those usually go into the carīs frame.
As you see, there a lot of things you can test. I would suggest you first try to get the system noise free with only one amplifier installed.
Steph |
|
|
| TO-3 |
| quote: | Originally posted by wally91chevrole
Aight yall. Heres my prob. I've got a 91 Silverado and I have BAD engine noise on my subs and my tweeters. I have an Audiobahn A8000T amp hooked up to my subs and an Audiobahn A6004T 4 channel amp on 4 tweeters. I regrounded all my grounds in new places and was SURE to make a solid connection. I also purchased some Rockford Fosgate dual twist signal cables for both amps. I thought for sure this would eliminate the engine noise. But its still there. Before I start the truck up, everything is chrystal clear. When I start the truck the subs rumble really low and the tweeters make a high pich buzz noise. Ive tried messing with all my settings and nothing changes it. Adjusting the level only makes it louder or softer. What can I get to eliminate this engine noise or what can I do? I've got my power wire that runs from my battery, through the firewall, down the passengers side of my truck back to my amps. The wire is 4GA from the battery to a splitter in the truck and then the wires split to two 8GA wires. One of those runs directly to my A6004T amp and the other runs to an Audiobahn capacitor and my A8000T amp. Each ground is in a separate place on the frame of the truck and are 8 GA wires. My signal cables are only 6.6ft and run from my CD player down the middle of the truck to the amps. The CD player is a Pioneer DEH-P9600MP and is only 6 months old. I may also point out that before I had the A6004T amp, I had a Sony 4 channel amp and there was LITTLE engine noise. None on the subs. Now that I put in this new amp, Its gotten way worse. All help is appreciated.
This is what I've done to try and diagnose the problem:
-Unhooked the signal cables from amp (noise stops)
-Unhooked signal cables from headunit (noise stops)
So now I KNOW my signal cables aren't picking up the noise and my amps are fine because the noise stops when no signal cables are connected
-Tried all steps found at http://www.crutchfieldadvisor.com/I...rint=1&page=all
- I have not yet purchased a noise suppressor because I wanted other opinions. Acording to what crutchfield says, I need a noise suppressor to hook up to my power wires of my head unit (power line noise suppressor). Will this help? I've read a few bad things about Pioneer head units having bad engine noise problems (not very happy about that) through the pre amp outputs... If i KNEW the suppressor would help i would buy one because i really like my CD player.
What are your opinions? |
I had that problem before with my Saturn. I did a lot of different things to get the noise to go away. I found out that the chassis, of my car, was spotwelded which increased the chassis ground to the amplifier systems' ground resistance. I ended up running a ground wire from the battery to the chassis ground point. This made the noise go away.
I am not a big fan of isolation transforms as they mask your underlying problem and add frequency distortion.
Another thing you might try, is increasing the size of the alternator-to-chassis ground. Most OEMs are too small for larger systems. |
|
|
| sagarverma |
best still.use a big inductor in series with the power line which enter the system.connect one end of inductor to the wire from battery and other end to amp system i/p power lines
i had same prob,ditto same in my car.all silent and great at car engine off but buzz(like small crackers phat phat phat phat sound) came in when engine runnin.
its called engine whine(someone in forum told).i used an inductor from smps of an old pc.also used 100nf caps at points where power just enters the amp system and the noise was all gone. |
|
|
| TO-3 |
| quote: | Originally posted by TO-3
...
Another thing you might try, is increasing the size of the alternator-to-chassis ground wire. Most OEMs are too small for larger systems. |
Opps |
|
|
| buloi123 |
| isolate the ground you are using for your amplifier to the main ground by a diode. Anode at your amp's ground. |
|
|
| nine76chris |
TO-3 is correct. Your amp is actually drawing power from the ground conductor of the RCA's not the power ground wires.
Current flows along the path of least resistance, and steel is an awful conductor compared to copper...even lots of steel. Run 4awg power wires(+ and -) directly to the battery terminals, then
throw all those noisesuppressorwhatchamacallits away. |
|
|
| wally91chevrole |
Well heres what I've tried so far. I emailed Pioneer and cardomain for more ideas.
-Tried a return ground from the amps to the cd player (noise was still there)
-Figured out the noise also occurs when the key is in the "ign" position but the noise is half as loud/
-Moved my RCA cables all around to check for change in sound (no change)
-Tripple checked EVERY power wire and ground from start to finsih and ALL appear perfect.
Also I want to point out that i have (4) 4x6 speakers hooked up to the speaker outputs on my headunit and there is NO engine noise comming from these.
I've been led to believe that my problem is a mix between alternator, distributor noise, and also some type of electrical interference.
And as for Audiobahn not being a high end product, I don't know if can believe that or not. I got the mono amp from a friend and he didn't have this problem at ALL. And my sony amp was doing the same but it wasnt as loud so I'm sure its not my amp.
I was told grounding the amps in two different places was a bad idea but if i grounded them in the same place, one ground would need to be extremely long to reach the other so i shortened one and was SURE to get all paint off of grounding area and im POSITIVE my grounds are VERY secure.
Would a new ground from my battery directly to my frame really make that big of a difference in my noise? I might have to try that.
Please if you have any more ideas and are sure you know what your talking about, please tell me. I'm so close to just giving up and selling everything because this is getting outragious. I've done EVERYTHING and the noise has yet to even begin to fade. Thank yall for your help. |
|
|
| wally91chevrole |
| one more question... would a quick fix be to wire my amps up using the high end input and not the RCA inputs? would this fix the problem? also will this effect the sound quality? |
|
|
| sagarverma |
try inductor from between amp power i/p and battery i.e one end of inductor from battery and other going in amp i/p.
i had same prob., 100% same.this simple thing did d trick.
try it.a computer smps inductor will suffice.:smash: |
|
|
| TO-3 |
| quote: | Originally posted by nine76chris
...snip... then throw all those noisesuppressorwhatchamacallits away. |
:up: :drink: |
|
|
| TO-3 |
| quote: | Originally posted by wally91chevrole
Well heres what I've tried so far. I emailed Pioneer and cardomain for more ideas.
-Tried a return ground from the amps to the cd player (noise was still there)
-Figured out the noise also occurs when the key is in the "ign" position but the noise is half as loud/
-Moved my RCA cables all around to check for change in sound (no change)
-Tripple checked EVERY power wire and ground from start to finsih and ALL appear perfect.
Also I want to point out that i have (4) 4x6 speakers hooked up to the speaker outputs on my headunit and there is NO engine noise comming from these.
I've been led to believe that my problem is a mix between alternator, distributor noise, and also some type of electrical interference.
And as for Audiobahn not being a high end product, I don't know if can believe that or not. I got the mono amp from a friend and he didn't have this problem at ALL. And my sony amp was doing the same but it wasnt as loud so I'm sure its not my amp.
I was told grounding the amps in two different places was a bad idea but if i grounded them in the same place, one ground would need to be extremely long to reach the other so i shortened one and was SURE to get all paint off of grounding area and im POSITIVE my grounds are VERY secure.
Would a new ground from my battery directly to my frame really make that big of a difference in my noise? I might have to try that.
Please if you have any more ideas and are sure you know what your talking about, please tell me. I'm so close to just giving up and selling everything because this is getting outragious. I've done EVERYTHING and the noise has yet to even begin to fade. Thank yall for your help. |
If you run another ground wire from the HU to the amplifier, you are creating a redundant loop. And the amp is already at the same potential is the HU through the RCAs. Go to the battery and you will have a good ground. Why? Because if you use the same gauge for power and return, the current to the amp will be the same as the current returning to the battery (privided the + and - are exactly the same length.
| quote: | Originally posted by wally91chevrole
one more question... would a quick fix be to wire my amps up using the high end input and not the RCA inputs? would this fix the problem? also will this effect the sound quality? |
Using the high level inputs is not recommended as you will be using the signal amplified by the HUs outputs and will decrease the S/N as well as THD.
Take a meter and measure from the RCA shield to the amplifier ground point. What is the differential voltage between the two points? |
|
|
| wally91chevrole |
| ok, with Cardomain.com's help and other idividual help, we've determined that the cause is a defect in my CD player. We determined this by touching a short wire to the shield of the RCA cable conneced to the head unit and touching the other end to the head unit casing itself and the noise STOPPED COMPLETELY. I was told there was some type of short in the headunit and i'm sending it in to be repaired or replaced under waranty. Thank's for everyones help. |
|
|
| TO-3 |
| quote: | Originally posted by wally91chevrole
ok, with Cardomain.com's help and other idividual help, we've determined that the cause is a defect in my CD player. We determined this by touching a short wire to the shield of the RCA cable conneced to the head unit and touching the other end to the head unit casing itself and the noise STOPPED COMPLETELY. I was told there was some type of short in the headunit and i'm sending it in to be repaired or replaced under waranty. Thank's for everyones help. |
Did you try shorting the case of the HU to the chassis? It still sounds like a ground-loop. |
|
|
| silver00spike |
I have the same thing in my tweeters. I have like 10" wires connecting the power and ground to the battery.
This noise is coming from the tweeters, as I turned up the gain to about 80%. It seems to be louder when it rains too :whazzat:
Pioneer Avic-N1 HU
Focal Utopia 165w
Kicker S10L7
Van Gogh 500.4 amp
stock 90 amp alternator
so...... try grounding the cage of the HU to the car? |
|
|
| TO-3 |
| quote: | Originally posted by silver00spike
I have the same thing in my tweeters. I have like 10" wires connecting the power and ground to the battery.
This noise is coming from the tweeters, as I turned up the gain to about 80%. It seems to be louder when it rains too :whazzat:
Pioneer Avic-N1 HU
Focal Utopia 165w
Kicker S10L7
Van Gogh 500.4 amp
stock 90 amp alternator
so...... try grounding the cage of the HU to the car? |
No. You have a ground-loop between your amp and HU. You need to make sure you have a solid ground on both units. |
|
|
| silver00spike |
| quote: | Originally posted by TO-3
No. You have a ground-loop between your amp and HU. You need to make sure you have a solid ground on both units. |
The amp is directly connected to the battery |
|
|
| TO-3 |
| quote: | Originally posted by silver00spike
The amp is directly connected to the battery |
Is the HU connected to the Bat as well? Sometimes the ground cables, in the OEM harnesses, are grounded to the chassis. |
|
|
| silver00spike |
| The headunit is grounded by the harness, which I assume is grounded by the chassis. So I should ground the HU directly to the battery? Should this solve my problem? |
|
|
| TO-3 |
| quote: | Originally posted by silver00spike
The headunit is grounded by the harness, which I assume is grounded by the chassis. So I should ground the HU directly to the battery? Should this solve my problem? |
I always connect every peripheral to the battery. That way I know what my ground is. Also, I ground locally to the chassis as well.
If the amps is still squealling after that, there may be something else going on. |
|
|
| silver00spike |
| well, I grounded the amp, and reciever to the battery, and still get a whine. It got better, but when its still very audible |
|
|
| rinox |
1) How old is yor car? More then 10 years ? (are there emi protection in spark distribution?)
2) DO NO CONNECT GROUND DIRECTLY TO BATTERY BUT WITH AS SHORT AS POSSIBLE CABLES TO CHASSIS (the chassis is the best "wire" you can use)
3) Remove the ground connection to the end of signal cable (near the amp) ... in my experience this will be the best solution (if point 1 e 2 don' t make effects).
At the end you can try small 1:1 signal transformer, but I don' t know where to find (installers?)..... this is the quickest solution but is the most expensive.
Hope this will help
:) |
|
|
| silver00spike |
| quote: | Originally posted by rinox
1) How old is yor car? More then 10 years ? (are there emi protection in spark distribution?)
2) DO NO CONNECT GROUND DIRECTLY TO BATTERY BUT WITH AS SHORT AS POSSIBLE CABLES TO CHASSIS (the chassis is the best "wire" you can use)
3) Remove the ground connection to the end of signal cable (near the amp) ... in my experience this will be the best solution (if point 1 e 2 don' t make effects).
At the end you can try small 1:1 signal transformer, but I don' t know where to find (installers?)..... this is the quickest solution but is the most expensive.
Hope this will help
:) |
car is a 1997. Could you explain step 3, I don't understand. Thanks for your help |
|
|
| nine76chris |
Spike, read my reply to this on page 1. I'll explain this best I can. This not written in stone and I'm sure some will disagree. Rinox..step 3.. he is suggesting you cut the ground conductors of you RCA interconnects which goes along with what I was saying in the reply. Though I wouldn't cut it, ya don't want your wiring all chopped up. A 100 ohm resistor in series with the RCA ground would work but, thats just a patchup. You want the grounds of the deck and the amp to be as close to one another as possible(ELECTRICALLY!). If the deck were in the trunk, 6" from the amp, both their power ground leads tied together at a single point them the noise wouldn't exist would it(Uh Oh... that'll draw some disagreement)? So wire them as if they were right next to each other. However, the ground lead of the amp must be the path of least resistance back to the battery and then the deck ground tied to the amp ground at the amp(ideally). If it is not, it will find an easier way, like through the RCA signal ground. This large current draw through the RCA ground causes a voltage drop across it, which looks like an input signal to an amplifier. See above or RINOX step 3. So why is it noisy only when the engine is running? Batteries supply DC power, alternators supply raw RECTIFIED AC or in other words DC with lots 'O ripple. When a signal caused by a ground loop appears at the amplifier's inputs....it amplifies it, but not all of it, ONLY AC(!), i.e....music and noise. Most audio amps won't amplify DC(as a whole). While a good battery is supposed to filter this out, a bad one will not be able to as well. Loose connections between battery and alternator may make the ripple worse, possibly creating a EMI/RFI induced noise problem. So now the deck ground and the amp ground are closely tied to one another
and the alternator is makin' all that noise and ripple... Fine. Who cares, as long as they BOTH see that noise on their grounds, etc. Oh and Rinox #2...yes i guess a big enough piece of steel will provide a better common ground than thin copper wires. I scratched out a crappy drawing with paint for ya. Hope this helps. Sorry for rambling. --Nine |
|
|
| wally91chevrole |
| Problem fixxed.. short in CD player causin it to send the engine noise through the RCA cables, sent it in for warranty n got it back works good now.... |
|
|
| DigitalJunkie |
(Just a FYI,while i'm thinking about it)
One other thing a friend and I discovered a while ago on his Mazda..
There is a Ground strap from the engine block to the firewall (connecting the chassis to the engine block/battery)
This was the *only* ground between the engine and chassis!
This wire was ~12AWG,and was *MELTED* on both ends!
NOT SUFFICIENT! :hot:
We added some more ground straps,and a fat one from the Batt (-) terminal to the fender and 99% of his problems are gone!!!
This might be something to look out for! :smash:
I went and cleaned/tightened the existing ground straps on my car,and added one more big one directly from the batt to the frame.
My car already had decent strapping,but I did it for the peace of mind. |
|
|
| Jack Crow |
Guys,
Wow that was a marathon.
Ive had a couple of wonderful noise makers in GM cars.
My least favorite was the electric fuel pump in the damm tank.
Any time that ran, it threw a buzz into most audio electronics from the factory stereo, and the two way radios.
No joy to change either.
The second was the resistance heater that was the rear window defroster.
One day my two way radios just quit, and the FM entertainment set was only able to pick up local stations. Somethign was clearing knocking the heck out of my RF front ends.
Took a while to find, but the control module that ran the rear defroster failed in the 'on mode'. When current runs across the resistor paste on the glass, it acts like a wide band noise jammer.
A miserable thing.
Either way, Im glad it's solved. Lesson learned.
Be safe
Jack Crow in Kuwait |
|
|
| DigitalJunkie |
The rear defogger? really?
Maybe the controller was a PWM type deal?
I once had a heck of a time with noise in a car audio setup..took me weeks to figure out it was from the "dimmer module" for the lights in the dashboard/gauges/etc...It was some kind of PWM setup,and was noisy as heck!! |
|
|
| Jack Crow |
DJ,
Let's look at the physics of all this.
When a current flows through a resistor made of particles, it makes a series of very small arc's.
Each arc is a tiny wide band rf source. Put a few million of these micro arcs in the space of the rear glass in a Buick. It made quite a racket.
Early microwave jammers were spark gaps in resonent containers.
Something to be said for the method.
The relay in the control module latched shut, and that's why the defroster turned on. I found it when I removed the battery cable and drew a fat spark.
Later dude
Jack Crow in Kuwait |
|
|
| silver00spike |
| for some reason, I can lose most of my noise when the rear defroster is off |
|
|
| Jack Crow |
Silver,
Me thinks your on the way to results.
First off, in this business you can't trust anything other than your self.
Ive just had a major run around with a set of generator controlers because the manuals lie.
Had to work up my own test tools and procedures. Guess what, my way works and refuses to fail.
So the same deal with our cars.
On my old Buick, the control box said the rear defroster was off, light was out.
Yet the welded contacts in the control relay made the indicator lie. The indicator was tied into the defroster timer, not the output circuit.
The unit was passing current like crazy into the resistor grid. When the key was in and turned on.
So if your defroster is off, and the noise went away, that's a pointer in the right direction.
Unfortunatly there is no easy way to solve this short of scraping the resistance heater and installing a blower motor combination. Then your trading one noise for another.
Good luck dude
Jack Crow
TDY Camp Arifjan, Kuwait |
|
|
|
