Popping or clicking sound or noise when using a USB cable connection with any music playback device (home stereo receiver, car audio, portable speakers with USB, etc) This sound is likened to vinyl record noise, popping and clicking. It is random and does NOT repeat in the same spot.
I’ve started this post to bring focus to this issue and to show a relationship to all similar USB related issues in this forum and will be hopeful that the OEM (Apple) will see it is a major problem to be address, ASAP.
The ongoing ‘thread’ (discussions.apple.com/thread/2581406?) beginning in 2010 spotlighting USB playback noise (Popping Sounds) with car audio devices, seam to be one of the same issue and I would advise all to test this by simply connecting to another (USB) playback device (if you don’t have one; try connecting to an in-store demo speaker/amp or home-receiver with USB)
My spec. is as follows; New iPod Touch 64, 4G, iOS-5.1 using iTunes (ver. 10.5.1.42) on a Win-7 Pro, SP-1
To validate some discussion on my part; iPod user since 2004 and have owned 5 different models. Professional background; audio recording engineer, cross-platform computer technician and OEM builder, multimedia engineer.
As of 10/2011, new iPod Touch (‘iTouch’) began making popping sounds with USB playback thru car stereo. I have never had this problem with any iPod prior to using the new iTouch 4G with iOS-5. Have NOT verified if this began after iOS-5 or iTunes 10.5 updates.
-Verified it was only thru USB, apart from PC connection (playback via USB thru iTunes, built-in iPod speaker, headphones or dock connection to a playback device are ok).
-Used various USB cables (Belkin and the original Apple USB) which made no improvement.
-Connecting to home-stereo (new Yamaha RX-V671) using USB produced the same problem; therefore it is not related solely to car-audio devices.
I hope this brief (and the feedback to follow) will be a motivating force for resolving this ongoing problem. I will open an Apple Support item on this issue.
Conclusive Testing with Repeatable Results:
By preparing five WAVE files for testing (of 3mins each) as follows; Silence (No Room Tone), 50Hz/-20dB single tone, 1kHz/-20dB single tone, BrownNoise/-20dB, and finally VioletNoise/-20dB (BrownNoise is simultaneous multi-low frequency tones and VioletNoise is simultaneous multi-high frequency tones). Playback was made through iPod USB port of a new (out of box) Yamaha RX-V671 Receiver.
The Test Results:
With playback volume set at around -28dB (typical 100w amp), the ‘Silence’ WAVE file produced no popping noise as was the same case with both 50Hz/-20dB single tone, 1kHz/-20dB single tone files.
However; when I played the BrownNoise/-20dB, and VioletNoise/-20dB WAVE files, the popping noise loudly occurred every time. This conclusively demonstrates that the iPod Touch/iPhone USB popping noise does exist and most likely related to how it processes that data thru a USB connection. The popping noise also had no relationship to the recorded amplitude and occured in a random nature each time.