I’m gonna weigh in here and say something that’s gonna be unpopular, but it needs to be said.
It’s possible to get excellent sound from a MacBook. You DO NOT need to invest in a dedicated NAS and an expensive streamer. NASes can make sense in a setup, especially if you want to stream music to multiple zones (or stream music to a single zone but need wireless for one reason or another). But if you have just one zone, and your computer is already there, they are overkill. As for "audiophile" streamers, I’m not going to claiming that streamers with no caps in the signal path and separate linear power supplies are snake oil. Some may be able to hear a difference over a properly set up MacBook, but we are talking last 1%. Unless you are already ’maxed out’ on your other components, my feeling is that there are other places to spend your money that will make a bigger sonic difference.
The key, however, is that the MB must be properly configured. As others have said, lose iTunes. For a while I used JRiver, but it was kind of unstable on my system so I switched over to Kodi (formerly called XBMC), and I haven’t looked back. JRiver, has several features that Kodi lacks, but I wasn’t using them so I don’t miss them. I have no experience with Audiovana and other software, but they each have their fans. One thing is certain -- iTunes is crap.
Next, select DACthe output devices in the Sound control panel, then go into Apple MIDI and select 24 bit 192 kHz (and verify that the DAC is already selected as the output device in MIDI). After that, go into your software (not iTunes) and find the option to configure output devices (it’ll be in one of the drop down Kenzie’s or possibly in setup). Choose the option corresponding to your DAC with the word "CoreAudio" after it. Then find the option for "Integer Mode" and check it.
If you are storing your music on an external drive, as educeus said in the previous post, it can be helpful to make sure that the drive does not share the same controller as the output device. Since the output de ice s using USB, then make sure your drive is connected either Thunderbolt or FireWire. (This may mean that you need to buy a new enclosure that is equipped with either FireWire or Thubderbolt and drop your drive into it.) if you are using your internal drive to store your music, then this is moot.
Now, if you still don’t like the sound you are getting, the first and least expensive piece of hardware you should consider adding is a USB to SPIDF converter. Run USB from the MB into the converter and then digital coax from the converter to the DAC. There are several out there. Personally I like the Peachtree X1. (I have also used the NuForce U192S, and sonically it was fine, but the driver can be finicky.) These converters will do 2 things. First, they reduce jitter by reclocking the signal and sending the reclocked signal over coax, which is more stable than USB. (The Peachtree X1 has two separate oscillators, one for multiples of 48 kHz and one for multiples of 44.2 kHz.) Second, they are a low cost means of stripping the power out of the USB. In other words, they do the same thing that those separate linear power supplies for dedicated streamers do, but at a fraction of the cost.
Good luck!
