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Russell L

macrumors regular
Original poster
Aug 10, 2006
242
40
San Francisco
I listen to a lot of my music these days in my car via the Music app on my iPhone 14 Pro Max using Apple CarPlay (wired). Much of the music consists of CD rips (44.1/16 ALAC) as well as downsampled hi-res music that I’ve purchased via the internet. Before copying them to my iPhone, I downsample the hi-res files to 48/24 because the iPhone reportedly can’t handle anything higher—or so I thought.

I wondered what would happen if I tried to copy an original hi-res file (96/24) to my iPhone directly, without downsampling it first: would it reject it outright, or would it downsample the file itself somehow? I tried that just now, and the whole file seemed to copy over intact, as far as I could tell. Looking at my iPhone music (via the Apple Music app) while the phone was plugged into my MBP, there wasn’t a way to verify the sampling rate of the file, but the file size showed that it was identical to the (huge) size of the original, hi-res file. Surprise!

So now that I’ve seemingly got a hi-res file on the Music app on my iPhone, would it play? The answer is YES: via CarPlay as well as via the iPhone’s tiny speakers. And it sounds pretty darned good in the car, too. So my question is, has Apple raised the limit as to the maximum sample rate that the iPhone Music app can handle? Or is my phone doing some automatic downconversion as it’s playing the file? I think that music can be streamed in hi-res via Apple Music, but it does seem that one can now transfer (sync) one's own hi-res files to the iPhone as well.
 

Helmsley

macrumors 6502a
Sep 4, 2017
689
333
Yorkshire, United Kingdom
I have no idea about the Music app, but as I understand it, iPhone hardware is limited to 24-bit/48kHz (without a DAC) so anything higher than that will be downsampled.

Most car head units don't support 48kHz+. I believe Car Play, wired, is 16-bit/48kHz (maximum).
 
Last edited:

Russell L

macrumors regular
Original poster
Aug 10, 2006
242
40
San Francisco
Thanks. I suspect you're correct about CarPlay, so there must have been some downsampling going on when I played that 96/24 file. It sounded good regardless, but since it's taking up significantly more space on my iPhone, I'll delete it and downsample it myself before copying it back to the iPhone. Trouble is, I've got lots of hi-res music that I've downsampled for CarPlay purposes, and these downsampled files take up a fair amount of space in my Music Library on my Mac, in addition to the original hi-res files. Oh well........
 
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