Whiskers

Hi All!!!

I just tried out the MP3 player feature of the I-VES in my car this morning. For the most part, it's pretty cool. The sound is better then I expected for FM modulation and song list displays on the rear monitor. The problem is that it sounds like a dentist's drill when I drive (pitch changes in tune to the engine revs). I called my Acura dealer who installed it and the only thing they can think of doing is changing the radio station that it is using (but right now I am on the weakest station). I am thinking of buying one of the adapters that plug into the Aux port of the radio, I know one you have to splice for the Nav and the other you don't (we are waiting for the test results). I have read here that you can also get the drilling noise even when using the Aux input adapter, is this true? Doesn't anyone know how to stop the drill ??? My teeth hurt while listening to Abba

Thanks,
Warren

elduderino

The noise you are hearing is not inherent in FM Modulation. I won't try to explain what causes it because the resident insurance adjuster gets all up in my face, but let's just say the three most likely contributing factors are:

1) two devices connected to each other by an audio line which have ground connections that electrically are not identical
2) power coming into a unit that is not sufficiently filtered internally or externally
3) noise being radiated into a component (I have decided that the Airbag ECU below the radio on the tranny hump is a known bad actor, after my and others' experiences with it).

I don't know who is making the OE system for Honda/Acura. I consult for a company that made the Toyota Sienna gen 1 VES system, and to get rid of this kind of problem they had to install a big Radio Shack power filter coil on the power wire of the VES (which means they didn't build the right kind of filtering into the unit, the dumbasses). So they can try installing a noise filter on the power wire into the unit. Most dealers don't install their own VES units, they usually sub it out to what's called an "expeditor". They will usually have access to a filter (although they may not know it - many expeditors focus primarily on leather installs). Audiovox includes a filter in their wiring harness, and both Audiovox and Rosen (two common aftermarket video suppliers) sell their dealers standalone noise filters (Rosen's is built into the unit itself.)

Since systems adapted for OE use never use RCA cables on the installed harnesses, you can't really install an RCA ground-loop isolator like we discuss on lots of aftermarket product installs. Since these systems usually ground the FMM with the rest of the system, a ground loop here is unlikely, so it shouldn't help anyway, theoretically. There used to be antenna noise filters, and one of those might get rid of a ground loop through the ground shield of the antenna connection... but that can be tested by unplugging the FMM antenna connection entirely, but leaving it in place. The FMM will broadcast enough to be audible (if they leave the antenna unplegged from the radio especially) and they can see if the noise goes away. If it does it's a ground loop through the antenna connection, and one of those antenna filters should help (but might mess up the reception...).

But it might be something as simple as re-routing or re-positioning the wiring and the FMM to avoid the Airbag ECU. Not too easy, not a lot of room in there, but the FMM sitting on top of it might have a problem... and a couple of inches has made a difference in my experience.

Let us know what you find out...

Whiskers

I send this info to my dealer. I am not inclined enough to start fishing around there. Thanks a lot!!!

bhjazz

A couple of things to consider:

Is this the stock MP3 player? Yikes. Make sure the ground connection is at the same location as the ground for the unit it is plugged in to.

Or, with the car running, experiment with different ground locations. There is a possibility that a location just inches away can be completely quiet.

Search Google for copper foil, copper shield, or silver foil. Use these items to wrap any cables or odd connectors with the stuff. It provides a great DIY shield. In fact, this stuff is always used for DIY (this may help your searching!)

Take it to a professional install shop. This is what they do for a living.

Dan Martin

I-VES is the OEM drop down DVD player not the MP3 player.

elduderino

Actually, I'm fascinated to find out what happened when it went back to the dealer...

Please, anyone with engine noise, don't do any of these these things unless an organized T-shoot process fails you. It's a random batch of things that worked once. Until you know that you have a ground loop, or until you know that you have inducted noise, why spend a lot of time throwing spaghetti at a wall?

And having been a pro, I can tell you that most installers are pros at avoiding engine noise troubleshooting, not actually doing it. They begrudginly t-shoot their own installs, but something like this, most installers won't touch.

Whiskers

elduderino. I sent an e-mail to the dealer with basically what you said. I havent heard back so I think I scared them. It's not a hot item for me, maybe I will bring it up again when I am back in.

Thanks

bhjazz

Once again, thanks for making me look like an idiot. I should know by now that anything I post will have a follow up like this. Gee, and your PMs were so polite... The items mentioned are neither random nor have they worked just once. I know many installers who have had to use similar procedures time and time again. You are forgetting that the entire car chassis is a ground plane. This is why you could literally sand off some paint and ground something anywhere. This is why some installations will suddenly whine when the rear defogger is turned on. Why? Because the point you chose to ground something at doesn't have the same ground potential. You even mentioned it when you said:

1) two devices connected to each other by an audio line which have ground connections that electrically are not identical

But I suppose if I wrote it, then it must be wrong. And if I'm wrong, then I suppose people like David Navone and Richard Clark are as well. Maybe you should hang out on their forums before checking my comments.

As for copper shielding, maybe Sony is run by morons as well. Their Sony Mobile ES XR-C900 has a copper chassis for shielding. Or is that there just so it looks good on the showroom floor? If I'm wrong, then I guess I could run unshielded wires all over the car because secondary shielding is just not necessary.

Here's a comment from David Navone himself. (for the uninitiated, Navone is a physicyst, EE, and has spent the last 25 years working with automotive electronics.)

"...In a car, looking for a "good" ground can be a never ending task. The reason? Because the car's chassis is used as a ground return for ALL of the car's electrical accessories. Relying on any particular point on the car's chassis to be a "reference" ground will inevitably lead to problems due to changin ground currents. For instance, ground currents will change with the rear window de-fogger is activated thereby changing the so-called "reference" ground point.

The secret of noise-free automotive entertainment lies in isolating our components from the car's chassis -- not in connecting to that chassis. If you have to worry about where to ground something, then you're in for problems. Solve one problem, and another is sure to appear. .."

Funny thing: he mentioned the read window defogger and shielding, too. I can't imagine why he would also mention "looking for a ground" either. The rest of the thread is here http://www.carsound.com/UBB/ultimate...=003994#000008.

So, yeah, please, anyone with engine noise, don't do any of these these things. Keep the alternator whine. It's good for you. You'll take it and you'll like it.

elduderino

Look, pal, I didn't say not to follow your process - I said to follow an organized t-shoot process FIRST, rather than randomly starting to wrap cables in copper foil. I stand by that statement.

I am not trying to make you look like an idiot. You seem oversensitive. I did not use the term "moron" - you did. I am disagreeing with some of your statements in a public discussion forum. I have not made any personal comments about you. When I make ANY recommendation about noise t-shooting, please be assured that it's based on almost 20 years of empirical and theoretical grounding, and that it's not about you, buddy. I'd say exactly the same thing whether you were posting or not, trust me.

You write as if all noise is ground-loop noise. I acknowledge that ground-loop noise is the most common type, but it's not all there is, and I also fail to see what wrapping connectors in foil will do for ground loop noise.

Again, if you re-read your post, you are recommending to wrap "odd" connectors with shielding. There is no reason to wrap connectors with shielding unless you determine, through an organized t-shooting process, that you have inducted noise, rather than ground loop noise or power-input-line noise.

No, I don't worship at the altars of Clark or Navone... they are smart people, but I'm not kowtowing to them. Clark has been quoted on this forum as saying that inductively-radiated noise is impossible in the car. He seems to have made contradictory statements about this over the years, and I have emprically observed inductively-coupled noise in a car, so I'll go with my own observations, thanks. Clark and Navone have also been paid to recommend Monster Cable twisted-pair RCAs... why? The only benefit twisted-pair can possibly have is rejection of inductively-coupled noise.


So calm down, breathe into a paper bag, drink some decaf, and consider that maybe it's not about you, man.

Bass Mechanic

lets try to play nice.. and im an insurance AGENT not an adjuster.

elduderino

Whoops. My bad. Sorry about that.

elduderino

"In a car, looking for a "good" ground can be a never ending task. The reason? Because the car's chassis is used as a ground return for ALL of the car's electrical accessories. Relying on any particular point on the car's chassis to be a "reference" ground will inevitably lead to problems due to changin ground currents. For instance, ground currents will change with the rear window de-fogger is activated thereby changing the so-called "reference" ground point.

The secret of noise-free automotive entertainment lies in isolating our components from the car's chassis -- not in connecting to that chassis. If you have to worry about where to ground something, then you're in for problems. Solve one problem, and another is sure to appear.

Ohm meters are useless because as soon as the engine is started, ground currents skew the readings. (And we only have engine noise when the engine is running, eh?) "

Anyone want to tell me the useful information in this above paragraph? All I can find is this:

"If you have to worry about where to ground something, then you're in for problems."

Sounds like he's saying to NOT spend time looking for the perfect ground point.

And I will disagree with the characterization above about the rear window defogger. I believe, based on past posts, that Bass Mech would agree that the different load on the alternator is to blame for increased noise with the R-W defog on... not greater ground currents.

Whiskers

I invite both of you to my place to get rid of my whinning noise....

Bass Mechanic

Elduderino is exactly correct, if anyone thinks that the ground reference voltage with respect to the battery changes enough to be a factor when the rear defroster is on is in la la land. think about it. the amount of surface area of metal to make up a car chassis equates to a conductor probly about the size of a 2-3 inch diameter solid wire.
the only way your going to pick up alternator noise from the defroster is if you ran a RCA cable parallel to the defroster wire itself.
what is really happenning in this secenario is that the equipment having different ground potentials because of a bad ground or that the input and output of the 2 components have different impeadance and or different reference ground in the output signal of one component to the input of another component.
when you load the electrical system by turning on lights or a defroster you magnify the the difference between the peaks and vallys of the signal produced by the alternator. which is not AC but rather a pulsed DC signal.

Bass Mechanic

he he sure buy me a ticket to NJ and ill be happy to take care of it.

had to comment here. i just insured a guy that lives in NY. he is getting a house here in colorado (paying cash) he will continue to live in NY for the next 6 months and has invited me and my family for a free personal tour of NY. the best part is he actually works for NBC and has also invited me to go backstage on the today show! he also said i could be on TV! how cool is that?
we are making plans to be in NY for Christmas. that should be the best time of the year to visit.

Whiskers

Very cool. Rockafelller center during the holidays is way cool.

elduderino

so, was the noise issue ever fixed?

Whiskers

Thanks for the follow-up. I didn't do anything and for some reason it is not that bad anymore . But as you saw in my other thread, I am thinking about going the Aux input route instead of FMM.

Thanks again....