The article was informative, certainly. I recall reading articles among Benchmark's audio application notes then following a link, but I couldn't find the item I remembered after a quick look recently.Can you please share a link to that blog? Very curious as to how all that works. Thanks.
I did find an item on playing hi-res from iPad which said:
More detail in the article iPad streams high-resolution audio to Benchmark DAC1 (there's also a pdf version) including some testing. That's interesting, but not about upsampling (in fact it's confirming no downsampling). I also found a brief reference in another article Computer audio playback setup guide to Apple's upsampling which was less sanguine and more qualified:... the iPad can transparently stream high-resolution digital audio to the USB input of DAC1 converters. Even more remarkable, the iPad is able to wirelessly stream a 96-kHz, 24-bit audio file via Wi-Fi without losing sonic quality.
Although the quality of the sample-rate conversion in iTunes is surprisingly good, it is an unnecessary DSP process which is best avoided.
Both interesting articles. Now it's possible I conflated the two items and there is no more detail via Benchmark on Apple's upsampling quality. Or there is something, but I can't find it. That's all I can say for certain at the moment, sorry.