“Alternator whine” on Naviplus? (1 Viewer)

[CharlieS]

I’ve had a Naviplus for a couple of months now, and I’ve noticed that I get a high pitched hum/whine when I have the volume up but no sound playing and I am set on the aux source.

The noise varies by rpm, getting more high pitched when the rpms increase.

I thought this was called an alternator whine “back in the day”.

The louder the volume, the more noticable this is (seems rational, but thought I’d mention it).

It has the same behavior whether I am using wired USB or wireless via the CarKit dongle. It is the same sound in the android interface as it is in the CarPlay interface. There is no change in the sound if I unplug the CarKit dongle from the usb.

I thought that this noise was sometimes an issue with grounds, but the Naviplus doesn’t have any separate ground wires, it has its own harness that plugs inline between the head unit and the display.

Has anyone else experienced this? Are there common problem areas to look at? Can anyone offer troubleshooting advice for how to isolate where I the system it may be coming from? Are there wires that I could shield?

 

[catastrofe]

I’ve had a Naviplus for a couple of months now, and I’ve noticed that I get a high pitched hum/whine when I have the volume up but no sound playing and I am set on the aux source.

The noise varies by rpm, getting more high pitched when the Roma increase.

I thought this was called an alternator whine “back in the day”.

The louder the volume, the more noticable this is (seems rational, but thought I’d mention it).

It has the same behavior whether I am using wired USB or wireless via the CarKit dongle. It is the same sound in the android interface as it is in the CarPlay interface. There is no change in the sound if I unplug the CarKit dongle from the usb.

I thought that this noise was sometimes an issue with grounds, but the Naviplus doesn’t have any separate ground wires, it has its own harness that plugs inline between the head unit and the display.

Has anyone else experienced this? Are there common problem areas to look at? Can anyone offer troubleshooting advice for how to isolate where I the system it may be coming from? Are there wires that I could shield?

I just tried this with both wired and wireless connection. Volume on the head unit turned to "Max". No noise other than a low hiss that does not change based on acceleration. Granted, I was in "park" and not driving. I have the older unit with the round USB port.

 

[grinchy]

Is this unit doing any coax/digital signal shifting? I wouldn’t expect it to be, but if so , that was a source of hum when I did the external amplifier on my (different from TLC) ML head unit. The shield ground isn’t at body ground potential and if it gets on the same ground as the amplifier it pulls it up a little and makes hiss.
Unfortunately there isn’t a really good solution. I redid that plug using body ground and terminating the shield (dead ending it), worked fine but still makes me itchy when I think about it.

 

[grinchy]

Is this unit doing any coax/digital signal shifting? I wouldn’t expect it to be, but if so , that was a source of hum when I did the external amplifier on my (different from TLC) ML head unit. The shield ground isn’t at body ground potential and if it gets on the same ground as the amplifier it pulls it up a little and makes hiss.
Unfortunately there isn’t a really good solution. I redid that plug using body ground and terminating the shield (dead ending it), worked fine but still makes me itchy when I think about it.

Now that I think about it MOST is a digital signal . . .

 

[CharlieS]

I just tried this with both wired and wireless connection. Volume on the head unit turned to "Max". No noise other than a low hiss that does not change based on acceleration. Granted, I was in "park" and not driving. I have the older unit with the round USB port.

I have that older unit too, and get the whine in park. So definitely something up with mine. Probably installer (me) error…

 

[CharlieS]

Is this unit doing any coax/digital signal shifting? I wouldn’t expect it to be, but if so , that was a source of hum when I did the external amplifier on my (different from TLC) ML head unit. The shield ground isn’t at body ground potential and if it gets on the same ground as the amplifier it pulls it up a little and makes hiss.
Unfortunately there isn’t a really good solution. I redid that plug using body ground and terminating the shield (dead ending it), worked fine but still makes me itchy when I think about it.

I don’t know what that means, so I can’t answer the question. Electrical stuff is my kryptonite.

 

[grinchy]

MOST is the signal bus that the JBL HU uses to talk to the amplifier.

 

[kcjaz]

Not sure this is helpful but I once added a noise filter to the power in on a boat stereo that had “alternator whine” that resolved the issue. Here is a vid of a guy trouble shooting his alt whine and ends up with a filter plus magnets on power lines.

 

[CharlieS]

Thanks everyone.

@kcjaz after watching that video and a couple of others that popped up after it, I wonder if the Naviplus box is creating an additional ground path due to the way it is situated in the dash. I seem to recall a bare steel tube that runs across that area. If the naviplus case is touching it, I wonder if that might be enough to cause a ground loop? Looks like my next step is to take the dash apart and do a little bit of testing.

 

[kcjaz]

Thanks everyone.

@kcjaz after watching that video and a couple of others that popped up after it, I wonder if the Naviplus box is creating an additional ground path due to the way it is situated in the dash. I seem to recall a bare steel tube that runs across that area. If the naviplus case is touching it, I wonder if that might be enough to cause a ground loop? Looks like my next step is to take the dash apart and do a little bit of testing.

I’m no electronics wiz for sure but my basic understanding is that the alt whine is primary causes by a grounding path that is not intended followed by general EMF interference caused by power wires being in close proximity to signal wires. Cable separation is a challenge in the dash of a car. I think the filters and magnets are a bandaid to fundamental stray current and EMF issues.

I am way overrunning my head lights here and could be completely full of crap.