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#1
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
Ok so a few months ago I went all out and bought a really nice nice setup for my car. 2x12" subs, a 1500 watt 4 chanel amp, 16cm components and tweeters, and a new head unit. All 'Mac Audio' and a Pioneer BT70 Head Unit) Myself and a mate installed it in a weekend and it was savage. Got a new car, same car- honda civic, newer better model, did the install again, but this time serious problems. When the engine is on I'm getting interferance in the subs and speakers. It is a high pitched whine that goes up and down with the revs of the engine. Also, When I put in a new cd you can hear it searching through the cd on the speakers, its very annoying. I took it to a shop and the guy spent ages working on it, installed some little box between the RCA's and the head unit - to ground it, which helped a bit but the noise is still there. Possible Reasons for the problems: - The ground and power cables are aparantly not big enough. They are ok but I was told I should have huge cables to handle the power. - The RCA's and the power cable are going down the same side of the car, I was told they should be on oppasite sides. These are unlikely to be the sole reason for the noise, but they may contribute tot he problem. I'm going to redo the whole thing, at the weekend. However what was suggested to me is that the alternator is where the noise is coming from - aparantly the bearings can start to go and cause this noise, long before you notice anything wrong with the car. Everyone I talk to has a diffent idea on what the problem is - but as they say: "Opinions are like Arseholes - everyone's got one"... I need someone who Really knows exactly what they are doing. I've put over €1500 into this system and having it less then perfect is killing me! If anyone has any proper advice I'd love to hear it. Thanks |
#2
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
wrote in message oups.com... Possible Reasons for the problems: - The ground and power cables are aparantly not big enough. They are ok but I was told I should have huge cables to handle the power. - The RCA's and the power cable are going down the same side of the car, I was told they should be on oppasite sides. What size power cable do you have? Can you read the fuses on your Amplifier? What's the total number of amperes the fuses are rated at? (I.e. 3 x 20AMP fuses?) Definitely run the RCA's down the opposite side of the car to the power wire. Definitely do this first as it may well fix the problem. Cheers. |
#3
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
I will second that. Run the battery power cable down one side, and the
remote wire and RCA lines down the opposite side. That sound is called electromagnetic interference (EMI) and it happens because your amp draws a ton more current than your RCA lines are putting out which creates magnetic waves in the battery cable line. Also, make sure that you have a really nice ground for your amp. -- - AUSTIN BECKER "Mark" wrote in message ... wrote in message oups.com... Possible Reasons for the problems: - The ground and power cables are aparantly not big enough. They are ok but I was told I should have huge cables to handle the power. - The RCA's and the power cable are going down the same side of the car, I was told they should be on oppasite sides. What size power cable do you have? Can you read the fuses on your Amplifier? What's the total number of amperes the fuses are rated at? (I.e. 3 x 20AMP fuses?) Definitely run the RCA's down the opposite side of the car to the power wire. Definitely do this first as it may well fix the problem. Cheers. |
#4
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
That sound is called
electromagnetic interference (EMI) and it happens because your amp draws a ton more current than your RCA lines are putting out which creates magnetic waves in the battery cable line. True, EMI can be a cause of what we affectionately call "alternator whine", but in my experience, it is WAY MORE often caused by ground loops. Ground loops happen when the negative potential of one component (let's say your head unit) is different than the negative potential of another component (the amp let's say). The difference between these potentials creates a small voltage that travels across your RCA's and is amplified by your amplifiers (of course). The reason it fluctuates with the RPM of your car is that, well, it's complicated to explain. Suffice to say that when you rev your car it increases the output of your alternator and this changes pretty much all voltage potentials of the car (whether positive or negative). The problem with fixing ground loops is that very often it depends on the car. What works for one car may not work for another (or as you have seen, even the same model of car can have different problems). This is because (among other reasons) the car's body is, in a sense, a large piece of wire back to the negative terminal of the battery (or negative terminal to the alternator). With many cars, you may actually have different negative potentials at different points on the car body. So, how to fix it. First, always use the biggest ground wires you can. You want to make the negative potential of your components as close to the negative potential of the car body as possible, so they all match up. You also may want to try grounding your components at different spots on the car, for the reasons I already pointed out. But the best fix I have ever found is to ground every single component (including head unit) to the same spot, with large gauge cable. In my experience, this fixes about 95% of all ground loop problems. That way you are GUARANTEED to have the same negative potential for every component. If that is very difficult or impossible, simply run an 8 gauge cable from the ground of your amp to the chassis of your head-unit. You would be surprised how often that little trick solves the problem. MOSFET |
#5
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
I second what MOSFET said. Also, if no one has already suggeted this
(sorry...I read through all the posts fairly quickly) just try grounding your head unit and/or amp at a different location. And make sure the grounding location is a good ground, with clean, bare metal. Scrape any paint away from the surface if you have to. Rerouting the RCA cables is not as much as issue as proper grounding. If grounding doesn't work (which I suspect will eventually fix your problem) then try rerouting cables....but I don't think you'll need to, and it's a lot of work to boot! Tony -- 2001 Nissan Maxima SE Anniversary Edition Clarion DRZ9255 Head Unit, Phoenix Gold ZX475ti, ZX450 and Xenon X1200.1 Amplifiers, Dynaudio System 360 Tri-Amped In Front and Focal 130HCs For Rear Fill, Image Dynamics IDMAX10 D4 v.3 Sub 2001 Chevy S10 ZR2 Pioneer DEH-P9600MP Head Unit, Phoenix Gold Ti500.4 Amp, Focal 165HC Speakers & Image Dynamics ID8 D4 v.3 Sub |
#6
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
Tony F wrote:
I second what MOSFET said. Also, if no one has already suggeted this (sorry...I read through all the posts fairly quickly) just try grounding your head unit and/or amp at a different location. And make sure the grounding location is a good ground, with clean, bare metal. Scrape any paint away from the surface if you have to. Rerouting the RCA cables is not as much as issue as proper grounding. If grounding doesn't work (which I suspect will eventually fix your problem) then try rerouting cables....but I don't think you'll need to, and it's a lot of work to boot! I'll give that a third. First thing: try regrounding the deck. If it has a poor ground wire and is grounding through the antenna or chassis, you can easily get ground loops. Or disconnect the deck's ground wire so it ONLY grounds through the antenna and/or chassis. Or hook a ground wire to the deck's chassis... several easy options to try. Having the power and RCA feeds to the amp separated will help avoid other types of induced noise getting to the amp, but it's not related to alternator whine or to the "CD loading" noise. FYI, I had similar noises in my system, until I added a crossover between the deck and the amp... then the noise vanished. I rigged everything to a common ground, to a common filtered power, added a relay for the deck so it was drawing power directly from the battery... nothing worked until I put in the crossover. Noise problems can be very strange and elusive sometimes. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 0604-1, 01/24/2006 Tested on: 1/24/2006 9:57:11 AM avast! - copyright (c) 1988-2005 ALWIL Software. http://www.avast.com |
#7
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
FYI, I had similar noises in my system, until I added a crossover between
the deck and the amp... then the noise vanished. That's interesting. Usually it's the other way around (I had an EQ that always created ground loop problems when it was installed between the deck and amp). MOSFET |
#8
Posted to rec.audio.car
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Help! Install Problems - Interferance in Speakers
MOSFET wrote:
FYI, I had similar noises in my system, until I added a crossover between the deck and the amp... then the noise vanished. That's interesting. Usually it's the other way around (I had an EQ that always created ground loop problems when it was installed between the deck and amp). Yeah, I know, that's what really weirds me out about it... I was putting off adding the crossover because I was afraid it would make matters worse (especially as it's a really cheap-cheap unit), but when my Punch75 sub amp blew up and I had to rewire things to run the sub off two of the four channels on the main Kenwood, I had to add the crossover... and bingo, the noise was gone. I'm not gonna argue with success though, as long as it works! --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 0604-1, 01/24/2006 Tested on: 1/24/2006 2:43:28 PM avast! - copyright (c) 1988-2005 ALWIL Software. http://www.avast.com |
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