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AVH-4100NEX w/iPod via USB static/audio issues.


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This has been reported by several people, so I thought I should post it here. The issue is with intermittent, random bursts of static when using an iPod through the USB ports (1 or 2). Here is a video demonstrating the problem (most evident around the 2:00 mark):

 

 

I tested with 3 different 6th Gen iPod Classics (160GB Fat, 120GB, 80GB with flash memory conversion), as well as a 30GB iPod Video (5.5 gen). All exhibit the problem. Tested with both the Pioneer CD-1U201V (iPod cable) and a genuine Apple 30pin/USB cable.

 

The noise only occurs with the iPod, not with any other source (Android phone/radio/CD etc).

 

The unit (shown above, manufactured March 2015) was sent in for repair under warranty, and came back with the same problem. It was then replaced with a new unit by Pioneer (manufactured July, 2015). The new unit also has the issue. The head unit was tested outside the vehicle, as well as installed.

 

Not sure if it occurs with iPhone or iPod Touch, or on other recent NEX models.

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Curious.  What format is the song encoded?  Encoder?  Version?  Bitrate?  All the good stuff we typically don't care about until there's a compatibility problem....????

 

I noticed you used only the one song.  Does it occur with other specific song?  Any song?  Compare encodings, encoders, versions, etc.

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If I recall, the song above is a 192 VBR mp3, encoded using iTunes. I used this track because it was easy to hear the static/noise over it (the noise can be obscured somewhat by a louder track), but the problem seems to occur on any other music played as well, regardless of bitrate/encoding (there's a bit of a mix of them in my collection).

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I have same problems with AVH-X8700BT (european version of AVH-4100NEX). I  tested with 2 different 6th & 7th Gen iPod Classics (120Gb HDD and 128Gb SSD) with ALAC and AAC files only!!!

 

Just I have a problem with a low framerate from the rear camera. If I turn on the ignition and turn on the rear gear, until the unit is fully loaded (no warning signs) we have normal framerate. As soon as the unit loaded, the framerate drops and moving objects on the screen move jerkily.

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None of these songs are 2nd or later generation encodings, right?

 

See if you get the same distorted sounds if you play just CBR songs.

 

I know the media charts list VBR as compatible, but they don't specify a maximum average bitrate.  Higher bitrates are given with (CBR) next to it, such as 320 kbps (CBR).  I take this to mean only 320 kbps CBR are compatible, since you can only encode 320 kbps mp3's in CBR mode.  I think the max for VBR is 256 kbps or thereabouts.

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Oh, BTW...

 

This may be in part due to iPod firmware.  I don't believe the file itself is streamed to the head unit via USB connection but rather streamed as decoded audio (not certain whether analog or digital).  Just for proof of this is the fact that ALAC files can be played through the iPod... and ALAC files are not compatible with the head unit itself.

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None of these songs are 2nd or later generation encodings, right?

 

See if you get the same distorted sounds if you play just CBR songs.

 

I know the media charts list VBR as compatible, but they don't specify a maximum average bitrate.  Higher bitrates are given with (CBR) next to it, such as 320 kbps (CBR).  I take this to mean only 320 kbps CBR are compatible, since you can only encode 320 kbps mp3's in CBR mode.  I think the max for VBR is 256 kbps or thereabouts.

 

No second generation encodings here. Not sure if it's strictly an iPod firmware issue, as the iPod Video 5.5 Gen uses different firmware than the 6th gen and later iPod Classics (due to different audio hardware), yet still exhibits the static problem.

 

I'll create a playlist of CBR files to check...but if the iPod is doing the decoding and passing the signal along, it sounds more like a head unit issue. I should also note that my previous setup (DEH-P800PRS/CD-IB-100II adapter via IP Bus) worked flawlessly with the same iPods.

 

On edit: with 320 kbps CBR playback, issue still occurs.  

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Can't say for certain, but it sounds like the iPods are doing the decoding and passing digital stream to head unit. There's usually a synchronize signal or channel associated with the audio channel... at least there is in professional digital streaming....  or one unit acts as the "clock" and the other units patch into a "clock" signal for reference.  If a unit is are getting or sending a bad sync' signal, the result is  (I imagine) what you are hearing, with varying intensities and lengths.

 

I had two older Pioneer units also, both with the iPod ip-bus adapters, and every once in a great while, I'd get similar noise and even more rarely nothing but constant noise... using same iPod I use now (though iPod firmware has been updated a couple times).  The only fix was to physically disconnect iPod, display still showing under Pioneer control because iPod eject feature not working on head unit). let the iPod battery go dead enough th3e iPod turns itself off, charge and reboot... so IMO, it is the interface firmware of one, the other, or both the Pioneer and iPod units.

 

FWIW, a similar event occurs occasionally when connected to my Kenwood DNN990HD.  Same [workaround] solution.

 

As for your situation... IDK. :(

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Maybe you are using the internal amplifier of Pioneer 4100NEX. You can check your unit with an external amplifier ?

 

 

Actually I use both. External for front and sub, internal for rear fill. Both had the iPod static. Also tested with external amp on workbench (no internal), also noisy. 

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