Alias artifacts are audible when using Lightning to 30-pin adaptor with 1st Gen iPad mini on iOS 9.2.1

Originator:jeff
Number:rdar://24398702 Date Originated:2016-01-28
Status:Open Resolved:
Product:iOS Product Version:iOS 9.2.1.(13D15)
Classification: Reproducible:Always
 
Attachments: https://jeffvautin.com/wp-content/uploads/openradar/radarAudioArtifacts1stGeniPadmini.zip


Summary:
When using an iPad mini (1st Gen) with Lightning to 30-pin Adaptor (MD824ZM/A), there are audible aliasing artifacts present in the output of the D/A in the adaptor. Interestingly, this issue is not present with newer iPads running iOS 9.2.1, or with iPhones. The attached files are recordings made of this output, and starting around 0:13, and definitely around 1:00, you can hear the aliasing artifacts on the output of the iPad. The iPad output is also louder, even though the configuration of the devices is identical (only difference between the recordings is which device - iPad mini 1st Gen or iPhone 6+ - is connected).

We've tested multiple adaptors and multiple iPads, and we've linked the issue to the specific combination of the 1st Gen iPad mini and adapter  MD824ZM/A.

Steps to Reproduce:
1. Update iPad mini (1st Gen) to iOS 9.2.1.
2. Play music back via Lightning to 30 pin adapter MD824ZM/A.

Expected Results:
Clean audio.

Actual Results:
Audio with aliasing artifacts.

Version:
iOS 9.2.1.(13D15)

Notes:


Configuration:
1st Gen iPad mini

Comments


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