See the last post here by Musicfreak...
The hardware supports 24/192, but the operating system does not. The best you can do is optical out on a Mac at 24/96.
The way around this is by using a USB>SPDIF converter that comes with its own drivers. I use the M2Tech HiFace and can get up to 24/192 out of my Mac Mini.
And a related 24/192 thread...
These guys are 100% correct and Apple's documentation is misleading at best. The DAC chip is completely capable of 24/192 but the optical output is limited under Mac OS X to 24/96. I have booted Windows Vista Ultimate 64 bit a couple years ago and output 24/192 via the Mac Pro optical output, but this means nothing for any other piece of Mac hardware.
The hiFace will output up to 24/192 guaranteed. Here is a link to my review of the piece.
2011 Mini Which I think has the same DAC...
I know this is late, but I thought I give the spec's of my rig and my opinions.
Mac Mini 2011 12GB RAM (Very Important)
I run Sonic Studios "Amurra" It dovetails into iTunes for music management converts FLAC to AIFF and plays both AIFF and FLAC.
Amurra makes your iTunes MP4's sound amazing. Lossless FLAC / AIFF files are epic.
Keep in mind that 44.1 kHz, 88.2 kHz, 96 kHz or 192 kHz are sampling clock rates from the MAC, passed digitally to your PreAmp / Receiver using a digital SPDIF optical Toslink cable. It is still in digital format when it hits the receiver.
What's most important is what's in that digital data stream. Is it compressed MP4a (small files) or uncompressed FLAC (large files) The more data, the better the sound. 24 bit is better than 16 bit. You can clock as fast as you want but if there's less discrete sonic data it will not sound as good as lossless FLAC.
It's the same case in photography where most of the digital images are .jpg rather than RAW files. .Jpg are compressed and you can't do nearly as good a job in post processing (photoshop). Fact, there is less data.
Where the rubber really meets the music road is in your DAC. Digital to Analog Converter. Sorry to be elementary about this stuff and correct me if I'm wrong. It's still digital coming from the Mac Mini that's handed to your PreAmp and it's DAC. Once the DAC finishes the analog music is passed to your AMP and Speakers.
To be redundant, the more discrete data that hits the DAC the better the sound..... assuming the DAC built into your PreAmp is up to the task of processing lossless information.
Keep in mind my ears are 60 yrs old and blown out. That said Toslink optical from the Mac Mini to my Anthem AVM20 PreAmp sounded amazing. That's an 8 year old DAC in there. I wanted better.
I purchased a dedicated DAC. The Cambridge Audio DAC Magic Plus. $599.
This eliminates the Mac Mini Toslink bottleneck because the connection to the DAC Magic is USB.
This also eliminates the DAC in the AVM20 because it comes out of the DAC Magic on balanced analog XLR ports to the Anthe.
My speakers are Thiel CS 1.5
To my ears it's better than vinyl. You get the convenience of digital and the musicality of vinyl.
Availability. You are not going to find uncompressed music on iTunes. Although iTunes has a convert to AIFF function, I could not tell much difference. My Opinion, the Amurra software made MP4a's sound much better. Download the trial software.
Uncompressed / Lossless is IMO epic. The only place I found it was HD Tracks. You will see many different "qualities" available for albums on HD Tracks.
Cat Stevens, "Where do the Children Play?", 24 bit 192 kHz File size 297 MB
Rolling Stones, "Let it Bleed" 24 bit 88.2 kHz , File Size: 143.4 MB
Buddy Guy & Jr. Wells "HooDoo Man Blues" 16 bit 44.1 kHz 60 MB
Rolling Stones, "Let it Bleed" MP4a , File Size: 12.6 MB
IMPORTANT. All the lossless files listed above played just fine with Amurra on the Mac Mini and a Toslink optical cable to my Anthem AVM20. Just because it's a 192 kHz 24 bit file doesn't mean it can't be played from your Mac.
IMPORTANT As stated above, ya want a lot of RAM and you don't want a lot of other stuff running. Feed the big dog with memory and it'll que up 6 or so tunes for seamless song to song transition. I use the Apple "Remote" app to control iTunes on the mini. I use Apple Remote Desktop to tweak the Mac Mini and load songs from HD Tracks.
IMPORTANT: HD Tracks is cumbersome to use. It's not even close to iTunes friendly. When you buy an album (Most HD Track music is Album Only) it launches the HD Tracks Java Utility. Yes I said Java.
Do not too get caught up in bit size and sample rate of lossless music. Older recordings like "HooDoo Man Blues" with limited Reel to Reel tape technology for the masters, still sound amazing when they are played lossless. With 16 bit 44.1 kHz Jr's playing his harp in my family room.