ARB-82

Q: iOS 9.2 Distorted audio on Lightening to USB (garbled or skip/seek like noise)

As a follow up to this thread: iOS 9 lightening to USB audio clicks and pops

 

SITUATION
iPhone 6S Plus, iOS 9.2, Opel Ampera/Chevy Volt, Original Apple Lightning-USB cable


ISSUE
Distorted audio - stuttering and seek/skip like sounds - will occur when playing audio files over a Lightning to USB connection. The issue will arise anywhere between 3 and 15 minutes into a track or audio file. The issue will arise only when the phone is locked.

 

REPRODUCTION

1. Play a long audio file (>5 minutes) on a LOCKED iPhone running iOS 9.2 and wait for the audio to distort.

2a. Once the issue occurs, UNLOCK the phone and the issue will be resolved immediately.

2b. PAUSING the playback and waiting around 5-10 seconds until playing again will also resolve the issue temporarily.

3. Once the phone is LOCKED again (either auto-lock or manual) the issue will come back immediately.


NOTES
The issue can be predominantly heard using spoken word media. The issue will happen with music, but due to high dynamics certain music types can have, the issue might be less noticeable.


If you have a similair issue, please post your findings in this topic.

iPhone 6s Plus, iOS 9.2

Posted on Dec 9, 2015 1:03 PM

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Q: iOS 9.2 Distorted audio on Lightening to USB (garbled or skip/seek like noise)

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  • by csiffring,

    csiffring csiffring Apr 6, 2016 4:45 AM in response to ARB-82
    Level 1 (4 points)
    Apr 6, 2016 4:45 AM in response to ARB-82

    @ARB-82 You make a great point about one device working and another not working. I'm not very knowledgeabl about the inner workings of the phone. I had thought it  something specific to the iPhone that was interfering with the lightning audio signal. I have noticed an iPod Touch and iPad mini do not exhibit the same behavior. Maybe the cell signal is getting in the way of the audio or there is software specific to an iPhone? Any thoughts, you seem to know more about how the software works and it would be helpful to the community to find a solution.

  • by ARB-82,

    ARB-82 ARB-82 Apr 6, 2016 4:55 AM in response to csiffring
    Level 1 (20 points)
    Mac OS X
    Apr 6, 2016 4:55 AM in response to csiffring

    I do know my way around iOS, but unfortunately there is not much the community can do here. There are no 'legal' options to really delve into the OS to see what is actually going on. Are you sure the iPod and iPad are both running the same iOS version as the iPhone?

     

    If the interference is only when the iPhone is locked I would rule out cell signal, as the cell signal is active with or without the screen on. The problem under iOS9.2 was clearly a software issue as a locked screen would produce the issue and unlocking the phone would solve it right away.

     

    Your best options:

    1. Get another iPhone 6S (friend/family whatever) with iOS9.3.1 installed and check if it has the same issue.

    2. Always submit feedback to Apple. I know for a fact that all feedback will be read and properly categorized. If you keep your feedback as simple and concise as possible, it might be sent straight to engineers to look into. http://www.apple.com/feedback/

  • by ilzai,

    ilzai ilzai Apr 6, 2016 6:57 AM in response to ARB-82
    Level 1 (4 points)
    Apr 6, 2016 6:57 AM in response to ARB-82

    I'm also quite sure that the issue i'm having has very little to do with iOS versions and much more to do with compatibility with iPhone6s(plus) and Sound Blaster E5 (the same amp-phone combo  that csiffring is having trouble with).

     

    Just updated my iPad Air2 to the same iOS my phone has 9.3.1 and perfect lightning out -playback continues on iPad...

     

    @csiffring: Curious thing i noticed: when using the optical passthrough feature of sound blaster E5, those  "off-sync-static" bursts from locked iPhone where gone, but when using analog line-out from E5 glitches were back (of course). . . but even with optical passthrough ridding the more obvious glitches, there still was these  "harder to notice pops and clicks" from time to time...

     

    Perhaps Creative's support would know about this...

  • by warpbrained86,

    warpbrained86 warpbrained86 Apr 6, 2016 6:58 AM in response to ARB-82
    Level 1 (4 points)
    Apr 6, 2016 6:58 AM in response to ARB-82

    Thank you for posting that your issues were fixed. I was holding out and still using iOS 8.4.1 until I had an iPhone issue last week that required a restore. Of course a restore meant that Apple forced me to 'Update & Restore' as there was no option to restore alone. Your post put me at ease that perhaps the audio issue was fixed.

     

    I can now confirm that with an iPhone 6 using lightening to USB in my 2011 Chevy Volt has no issues. I listened for 1.5 hours in the morning on iOS 9.3 with no issues. I updated to 9.3.1 during the work day and drove home and had no issues in music, pandora, audiobooks, etc.

    I now have more than 12 hours of listening time and have had no issues with clicks, pops, lock-screen distortion, etc.

    I hope this helps somebody. Thank you all for chiming in on this topic.

    -Mark

  • by JLee1974,

    JLee1974 JLee1974 Apr 7, 2016 5:00 AM in response to TheTominator
    Level 1 (4 points)
    Apr 7, 2016 5:00 AM in response to TheTominator

    I had the same issue with my '13 Ram pickup. It turned out it was not the phone but the factory radio.

    I had the radio had to be updated by the dealer and the problem was solved.

  • by BMG1900,

    BMG1900 BMG1900 Apr 8, 2016 1:42 AM in response to ilzai
    Level 1 (4 points)
    Apr 8, 2016 1:42 AM in response to ilzai

    I have the same problem with a Soundblaster E5 / iPhone 6s plus combo connected via lightning cable. When using bluetooth everything is ok.

     

    I have no problems with my old iPad Air 2 and my new 9.7 iPad Pro. Everything runs fine. Android phone connected to the SB E5 via USB cable is also working flawless.

  • by raneman,

    raneman raneman Apr 27, 2016 3:09 PM in response to ilzai
    Level 1 (4 points)
    Apr 27, 2016 3:09 PM in response to ilzai

    Did anything ever come of this for you?  I'm just about to update to 9.3.1 on my 6s and hope that it helps.

  • by kcyip,

    kcyip kcyip Jun 5, 2016 7:16 AM in response to BMG1900
    Level 1 (4 points)
    Jun 5, 2016 7:16 AM in response to BMG1900

    Yes i am using iphone 6s plus and creative E5 , iOS 9.3.2 also have problem when playing music after screen locked.

    If the screen not locked then everything is good , and using bluetooth everything is ok.

     

    I also tried my ipad Pro 9.7 , no problem.

  • by AJ_Tsin,

    AJ_Tsin AJ_Tsin Jun 6, 2016 10:03 AM in response to kcyip
    Level 1 (4 points)
    Jun 6, 2016 10:03 AM in response to kcyip

    Also having issues clicks and pops when using USB audio it seems to occur a lot when the screen is locked. Sounds like vinyl pops but with a metallic tone.

     

    I am using an Audioquest Dragonfly Red USB DAC.

     

    This unit works flawlessly on my iPad Pro 9.7, Macbook Pro, and my Girlfriends 5S, but seems to have issues with iPhone 6S on 9.3.2...

  • by legendmc,

    legendmc legendmc Jun 10, 2016 7:57 PM in response to warpbrained86
    Level 1 (8 points)
    iPod
    Jun 10, 2016 7:57 PM in response to warpbrained86

    Hi Mark,

    I am just wondering if OS 9.3.2 is still holding strong with no playback issues. I have been holding out before leaving OS 8.x.x

     

    Thank you!

     

    Matt

  • by srichterss,

    srichterss srichterss Jul 15, 2016 2:32 PM in response to ARB-82
    Level 1 (4 points)
    iPhone
    Jul 15, 2016 2:32 PM in response to ARB-82

    Yes same issue here using Creative Sound Blaster E5. Did not experience it with iPhone6+ and I always keep the iOS updated. Switched to new iPhone6s+ with newest iOS and now I get an awful skipping/glithy/screeching sound during audio playback from any app. As already stated, it appears to only occur when the phone is locked. Must be some kind of power save mode that is messing with the data transfer.

  • by srichterss,

    srichterss srichterss Jul 15, 2016 5:04 PM in response to ARB-82
    Level 1 (4 points)
    iPhone
    Jul 15, 2016 5:04 PM in response to ARB-82

    HERES A FIX!!!... Sorta

     

    Running with the idea that its a power issue based on it only happening when locked AND the screen off. I don't know if anyone noticed, there is no distortion when the phone is locked but the screen is lit up. Unfortunately this state last only briefly before the screen shuts down again.

     

    Okay, here it is: Keep your flashlight running when locking your phone and the distortion is permanently gone. The obvious caveat is this drains battery. But it does prove that the issue is caused by a low power state or simply poor power management design.

     

    As an electrical engineer, I know that regulators need a minimum/constant load to help keep proper regulation, especially if the regulator bounces from low power PFM mode to high power constant switching mode. When the iPhone is in sleep mode the power consumption must be so minimal (or on the edge of PFM mode and constant switching mode) with only USB audio that the voltage regulation falters and some sort of data loss or other form of distortion occurs. Turning on the LED provides a much larger load that helps maintain proper power regulation (remains in constant switching mode). If this is actually the case the only software update that can fix this would be one that runs dummy protocols, while playing music in sleep mode, that consume more power. Otherwise this is a hardware issue that can't simply be fixed unless firmware is able to disable low power states like PFM mode.

     

    I tried running additional apps in the background, like map directions, at first but it wasn't enough. The LED for sure works though, along with keeping your phone from sleeping. Unfortunately my company's profile on my phone requires auto-lock and the max is 5 minutes

  • by srichterss,

    srichterss srichterss Jul 15, 2016 5:33 PM in response to srichterss
    Level 1 (4 points)
    iPhone
    Jul 15, 2016 5:33 PM in response to srichterss

    Won't let me edit so here it is...

     

    Additionally, I believe that the iPhone supplies the power to the USB interface of the DAC, since taping the power pin of the USB prevented the two from connecting. So if the amount of power required to run USB audio to your system is right on the edge of where the iPhones requlator switches from low (PFM) mode to high (constant switching) mode, there can be drops in the voltage during the transition that would disrupt the proper data transfer.

  • by srichterss,

    srichterss srichterss Jul 17, 2016 9:24 AM in response to ARB-82
    Level 1 (4 points)
    iPhone
    Jul 17, 2016 9:24 AM in response to ARB-82

    Another thing that can be tried is to connect through a powered USB hub. I don't have one right now to try with, but I've read other threads online that had similar issues and a powered USB hub significantly improved the audio quality.

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