Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Envithyx]

I just got my bike back today after having a few upgrades done.  One of them was I had the NIM installed after having a Zumo 665 installed a few weeks earlier.

What I noticed so far is that the aux port is not noise free like it used to be prior to the NIM install.  It is as if the NIM unit is introducing noise into the wire plugged into the aux port.

When I plug in the GPS with the radio on and aux selected, the noise of the NIM scanning and binding to the GPS can be heard as the units boots.  It sounds like a laptop computer plugged into speakers with a ground loop present.  Once the GPS boots; then the noise level drops considerably, but can still be heard.

My question is whether you can hear this noise as well if you have the setup to test, or if they did something on the wiring that created a ground loop.

I'm actually hoping it is a ground loop condition since that can be fixed.

One thing that leads me to believe it is a wiring issue is that the GPS actually interrupted the CD input a few times on the way home without having anything to say, and the GPS's XM music was playing through the NIM module.  When I rotated the input to aux, you could clearly hear when it stopped playing the XM signal via the mono NIM input and released it to the stereo aux line.

Thanks for any feedback, hope to get this looked at tomorrow.

[bissjim]

Have the dealer replace the NIM and see if the problem goes away.

[Envithyx]

So the NIM is a mini computer and when it gets wired in, it created a ground loop between it and probably the stereo or amp -- not sure which.

All I know is the source of the noise came from the NIM's audio in cable -- which is used to listen for the GPS audio signal to interrupt the radio.  Rightfully, the audio-in port shouldn't introduce noise back down the y-cable and allow it to leak into the aux port.

Harley actually told the stealer that not all products were meant to work together.    Go figure.  After all it's not as if this was designed to bridge the GPS and the radio.  What was I expecting! 

I also experienced the bug where XM leaks into other audio sources via the NIM's mono interrupt.  Harley told the stealer that it is a known bug that some music from XM will trigger the NIM and cause it to interrupt.  Supposed solution is to turn off XM when your not listening to it.  Problem is that it also interrupts itself taking the stereo signal from the aux port and downgrading it to mono from the NIM until it releases.  Slightly annoying, but until they change the frequency signal to something more discreet like a digital signal, it will always be a possibility.  Since the signal seams to be limited to audio frequencies; however, they should have used something like a dual tone multi-frequency signal much akin to the telephone system.  But I digress.

In any event, knowing that it was a ground loop and where it was created, I was able to get rid of the noise by installing a ground loop isolator between the NIM's input and the y-cable that splits the audio from the GPS to both the NIM and the Aux port on the radio.

There's still a low amount of hiss on the line, but I have to turn it up to about 75% in order to hear it.  Once the GPS is plugged in and attaches to the NIM, the noise level drops out almost entirely.  You have to be listening for it and I can live with it since once your on the road, you couldn't hear it.

[Envithyx]

Just in case someone wanted some kind of reference to the amount of noise I heard, here is my subjective db values based on the vol at 50%.  I have the Boom Audio Kit with the upgraded speakers, amp, and bass booster ports installed on a 2011 Ultra Limited.

Aux port from GPS without the NIM installed - Base line reference will call 0db.  Actually it pretty much was 0db.  I didn't hear any noise at all at 50% volume.

Aux port with NIM installed, GPS not plugged in - noise level up to about +18db.  Frequency of the noise is probably a composite of frequencies found in the 1kHz - 14kHz range.

Aux port with NIM installed, GPS plugged in and on - noise level up to about +12db.  Couldn't be heard riding, but could be heard when stopped at a light.

Aux port with NIM installed, GPS not plugged in, ground loop isolator installed - noise level down to about +3db.

Aux port with NIM installed, GPS plugged in, ground loop isolator installed - noise level down to about +1db.

Granted, most people can only hear a change in volume in 3db increments, but I've been blessed and cursed with ears that heard crap over 18kHz like it was stuck in my ear and apparently can notice 1db changes when its in the right frequency range.

Anyhow, again, this is all subjective measurements, but should give you an idea  of how it came across to me.

[TwoAlpha]

The comments on "XM leaks into other audio sources via the NIM's mono interrupt", sound *very* similar to what I'm experiencing. You can read my experience here ==> http://www.cvoharley.com/smf/index.php?topic=64779.0. Would adding a ground fault isolator help this problem? Any other suggestions.

[bissjim]

This is a known problem with the NIM. Replace the NIM with the new model which just came out about a week ago. Have the dealer order one as any they have in the dealers stock is probably an old model, which causes the problems you are experiencing, false triggering. Noise is being caused by a bad connection between the audio output of the GPS and the Aux input on the radio. Bad Y connector, cable etc. I do not know if the new model will solve the problem or create a new problem, time will tell.