My take on:
A Possible Design Fix for ”app’/CPU usage causing noise in music":
Obviously the user can pile-on the apps/notification until there is no end. This would (although possible) not be within the current limit of design spec. The quick fix would be to Auto-Limit or disable such apps, notification and emails when the device is being used for music (and videos would also apply here).
There is (always) limited resources within a given core processor/memory specification. If one intends to apply a plethora of simultaneous functions, then they should wait on the ‘next-generation’ of gadget devices. OR; just go back to using a laptop, notebook or tablet (which was the intent for these.
I recall my first buy-in to the development of ‘Cell-Phones’ and PDA’s where I had one of the fist real ‘Mobile Phones’ (a Norkia that I had to take a loan for) that was the size of a large walkie-talkie. Today apparently, the people in the closet who think this stuff up haven’t heard of the effects of ‘diminishing returns’ (thank you Dr. Deming) and apparently, the public all-to-well buys into it… and the wheel goes around & around.
So after I updated to iOS 5.1.1 and experienced the issue, I did a full reset at that point. Since re-adding all my music and having the iPod work fine, the popping came back (which was when I posted my last comment). Since my last post though, I followed the advice of theooriginal and it seems to have fixed the issue. Now I always let my car system start the iPod and Music app, as opposed to starting a song and then plugging in the USB cable.
As far as running apps and all communications (WiFi, Bluetooth, etc.) I haven't turned off communications or closed all apps; though I rarely keep an app open once I'm done with it. It seems that the issue is when I start a song on the iPod itself, and then plug it in. I usually did this since my stereo takes over control of the iPod, and it's much easier to browse my library on the iPod vs. car stereo. Once the stereo powers up the iPod, I have no issues throughout the day when I continue where I left off, it just seems to be when I plug it in with a song that I've started.
It's very strange, but the popping is definitely gone. I'll also add that I just updated iTunes in and around the same timeframe, but overall it seems that the above advice has been the most consistently successful. I will keep updating this thread if anything changes of course. Hopefully this helps out some others here too.
@egotripping: Thanks for the update, glad that helped. The issue of iPod control will most likely correct itself at the time you happen to upgrade the car stereo unit. It should have full compatibility. I continue to not have the noise and will stick with iOS 5.1 as a reference for now. The app thing was never an issue for me also.
Ignore the other rant if you wish, I think I was venting.
I just retro fitted a new head unit (RCD-510) to my mkv golf gti 2 days ago. I noticed the crackling and popping like an old record player the very second I played back from my iphone 4s (ios6) through USB. I then tested with 3 different USB cables, my ipad2, friends iphone 4s and ipod touch, and I hear the same static noise in all of them. I have gone through a few automotive forums and they all have the same feedback regarding this issue. My question is, if this problem is experienced by almost everyone, why isn't Apple doing anything about it?
There is a long going thread on this for the iPhone too. I really thought it was HW realted, as it is almost like a bad amplified sound. But, the more I played with my iPhone4, all the tricks of sync, turning the ounds up or down, I am more inclided to think it is a scheduler issue in the iOS working with the flow of the packets accross the transceiver for the USB connector.
It seems widespread accross various headunits, and devices and iOS versions. What seems to work for my is killing off apps and keep in the output of the sounds about 40%.
<<“…if this problem is experienced by almost everyone, why isn't Apple doing anything about it?”>>
@kaider: That is a very reasonable question to ask.
Being the one who started this thread (please note this thread is specific to USB noise and NOT CPU noise; see the beginning), I’ve researched the issue thoroughly and that info is presented here so reading it entirely would be beneficial. For myself, I don’t have the means to test version-5 products so not sure if the issue was carried over.
What I do know: what does help (for version 3 & 4 devices) when the noise occurs try the following:
Leave the unit connected, power down (Apple device) completely (OFF) then after say 10sec. power ON (boot-up) with USB cable still connected. This usually results in draining the (built-up) static charge that (I think) is causing the problem.
Please contact Service Support and/or APPLE Corporate notifying them of your continued problem with their product.
Yes, I am experiencing this problem with iPhone 4 plugged into my Dual deck via USB cable. It's an irritating crackly popping sound and it seems the easiest fix is unplugging the USB then plugging it back in, no more noise. However, this is only a temporary fix until the next time it occurs... It does make total sense that it would be static considering when I unplug the usb then plug back in it's gone.
this isssue has plagued me for about a year, on iPhone4 and iPOD. I was using a an Alpine headunit with USB. Since moving to a iPhone5 and keeping the volume level down, I had no issues. 2 weeks ago I purchased a new Peugeot that has dual USB connectors in the dash. I plugged my iPhone5 in and voila! cracking and popping noises.
I have used Apple products since I wa s a kid and I have always "felt" their quality was the "differentiator". I cannot say for 100% certaintly this is an Apple software or HW issue. But, I would expect the to comment since so many people have problems making the product quality perception sink.
I would agree it seems to be some scheduler issue, or cache around the buffer sending audio over USB. I also thought about how SCSI used to have a plug on the end of the chain. If you are old liek me and used Apple in the 90's you remember all the SCSI cables :~) So if USB is serial, maybe the bus is also contributing to signlas getting distorted.
All if it is theory.... worse thing is to have a new car, new iPhone and sound like a broken record player.
Thanks for adding the info regarding the iPhone5 and this on-going Popping-Noise Defect with iPod-Touch, iPhone and I hear iPad’s as well.
My take is; a dock-cable shield/ground issue that is facilitating audible static noise to the audio pin’s (of the connection) during a static buildup discharge from a power-charge and/or environmental conditions.
My report here has disclosed that; it is real, it is a big playback problem and that it is affecting millions of units and is product wide over many years.
Why is this such an Important Concern:
USB is a universal standard: An essential part of the modern (and future) multi-media experience, both in Home-Entertainment and Car- Entertainment systems rely (in part) on USB integration compatibility.
How so? USB integration is the pathway by which Digital Audio, Metadata and Remote Transport Functions are fed and read by the host system. It is how the user attaches the device which the system reads, displays all metadata content; Album Art, Playlist, Artist, song, etc. which the user can remotely navigate while watching his large on-screen display (and can also distribute that program (and function) throughout the home).
There are many applications and scenarios’ to this (I design and program them), it is essential for Apple to resolve the USB playback noise that is plaguing its products.
Do to the years involved with this defect, I’m now doubtful if Apple cares about it enough and will seek to make it public (in news media).
what is even more strange is that I was able to take the iPhone5 this evening to my old car and try the phone, untouched in the Alpine and theire is no popping. Plug it back into the Peugeot USB on the new car and the popping is there. Hummm, so it is very mysterious. Becuase the old car and Alpine would have the issue, at times. After fooling with the iPhone5, like volume, closing apps it would go away.
The other thing to consider here is that the iPhone5 has a lighting connector, and you would think new "guts" around that. So, maybe it is a software issue. Back to the theory of the scheduler. But then why does it happen in the new car, with the factory USBs?
I agree with you about USB. Claerly the functionality is far supperior to the 3.5mm jack solution. Which this new car of mine has and works fine. The car display has all the album art, and much more controls for playlists etc. Also the sterring wheel controls work on the USB link.
I think we have to get this ore public, ARS Tech or one of the MAC portals? Letters to them cc the Apple CEO? Pity...
I've had this issue for a while as well and as an engineer would love to solve it. I have done a ton of troubleshooting on this and have also discussed it with electronics engineers. Our hypothesis is the same as you've stated regarding the grounding issue. I have tested a Sony car DVD receiver with an iPod Touch 2nd Gen and iPod Touch 5th Gen with mostly the same results. The Lightning connector does not seem to make a difference. So my working hypothesis is that since the receiver is properly grounded, there may be a lack of grounding in the USB cable. I am considering a direct ground wire to the iPod case to test. Will post if I discover more.