You have 2 options.
1. Open up Audio MIDI Setup
It's in Applications/Utilities or you can search for the program using Spotlight.
Click on the device for your USB DAC. It should say C50 or something.
Click on the "Output" tab.
Set the format to 192kHz. It is probably stuck at 44.1kHz at the moment that's why Mac is downsampling your hires file down when sending it out to the DAC. ps Windows 7 also does it this way so it is not specific to Mac. It's just that these operating systems weren't originally designed for music playback.
The problem is that when you set it to say 192, it will output everything at 192. Even your 44.1kHz stuff. Which means a non factor of 2 up sampling. And most OSes do a frankly crappy job of up sampling.
So ideally you should be switching the settings in Audio MIDI to 44.1 when you are playing 44.1 stuff, and 192 for 192 stuff etc.
Not an ideal solution but it can work.
Which leads us to Option 2.
2. Use an Add In program to iTunes
These programs include "BitPerfect" - about 10 bucks, Audirvana Plus, Pure Music and Amarra with increasing levels of cost (going up to 100s of bucks).
These add in programs disable iTunes playback engine but uses iTunes as a way to catalog your music library and select songs/playlists. When they encounter a 96kHz file, they can automatically switch the sample rate accordingly so your DAC receives the data with bit perfect accuracy. Ditto with 192 kHz, 44.1kHz etc.
Most also have superior up sampling algorithms to upsample 44.1 to 176.4kHz or 192kHz (if you really want to).
They also provide memory play - loading the songs into memory before commencing playback. There's also generally an improvement in Sound Quality over regular iTunes.
ps Czarivey is talking out of his ass.
Thanks, Doggie! I didn't know I could adjust the Mac MIDI output by selecting the external audio device. I'll try it that way first to check out how it sounds. Just have to remember to reset it before I unplug.
I'm a hard-core vinyl head in my off time and I use a computer for work all day, every day. Never been too keen on mixing computers with pleasure as a result. Spreadsheets, data logging, feedback control, all fine. Music, video, games, not so much. Still, the convenience factor has me looking at the PC source more seriously and since I have a good DAC in the C50, I figure it can't hurt to try it.
Yes, JRiver for Mac also bypasses the OS's audio playback engine. So it will
adjust the sample rate according to the source file.
JRiver has the option to enable Direct/Exclusive Access to the audio device
and can also operate in Integer mode (all improvements in playing back
audio) provided you are using 10.6.8 or 10.9 - Integer mode was dropped in
10.7 and 10.8 - don't know why.
My main gripe with JRiver is that its legacy as a Windows application still
shows. It places menus/options in the weirdest of places that don't make
sense at times. That said, once you get used to it, it is extremely powerful and
flexible in what you can do.
FWIW, I have been JRiver almost exclusively these days. I really like its ability to
upsample everything to DSD2x which sounds better on my Playback Designs
MPS-5 and Teac UD-501.
I have recently upgraded my versions of Pure Music and Amarra to v2.x and
3.0 respectively so I may give them a test run soon to see if they will change
@Effischer, you don't have to reset it before unplugging because the setting
for 192kHz or 96 or 44.1kHz etc that you change is specific to the audio
device - in this case, your DAC. So it should not interfere with the settings of
your built in audio device in the Mac.
In case it wasn't clear enough the first time around,
The C50 has a MODERN DAC design housed in a classic/traditional McIntosh
enclosure so it does 32bit/192kHz over USB. So try to get your facts right
before shooting stuff out of your ass. Pardon the french.
"DIGITAL USB INPUT
1 (2.0, 32/192 Asynchronous)"
Also appreciate the info regarding the add-ins and your response to 77 on JRiver, Doggie. The note about resetting reminds me that I'm dealing with OS X, not something else. Don't always remember that OS X does what it's supposed to, not what it wants to. I finally drank the KoolAid a couple of years ago because I had so much trouble with stability on the WinTel platform my company supplied. Bought a MacBook Pro and run a virtual machine under VMWare for my company VPN. Gets me the super-stable Apple platform and prevents Win 7 Pro from crashing me out. What an improvement!
Anyway, since I'm very deliberate about adding or changing configurations, I'll check out my samples with the (thank you again) correct MIDI settings and decide where I want to go with add-ins. Have the long weekend to experiment, too. Have a great Independence Day holiday everyone!
Tried posting this yesterday, but something is up with A-Gon.
I got this,...
Your DAC will display the sample rate as set in Audio MIDI Setup unless your Player software automatically sets the correct sample rate for each file as it is played. [iTunes will not do this but there are add-ons that will, along with other music players].
The Audio MIDI Setup example below is from my office Mac so you won't see a DAC listed. On your Mac, click on the DAC in the left column. Whatever the sample rate is set to in Audio MIDI Setup is what will be sent to your DAC regardless of the file sample rate. Try it. Now change the sample rate in Audio MIDI Setup. View your DAC and note the sample rate it shows. It should match what you chose in Audio MIDI Setup.
You need Player software that will automatically and correctly set the sample rate for each file you play.