Apple Music Playback
Getting the best out of your music can often be a bit of a daunting effort, and playing back music through an Apple computer is no exception. There are numerous details to take care of to ensure that everything is done perfectly, so I've put together an article to help explain some of the easy tripping points.
Digital Audio Output
Often the headphone output on computers can be a bit of an afterthought. Apple is not nearly as terrible as many other manufacturers in this regard, however the sound you hear can be vastly improved by bypassing this output in one way or another. Currently there are five options for doing this, each with a few advantages and disadvantages. You have the choice of USB audio, optical output, Bluetooth, AirPlay and other network streaming.
USB / Optical
Using the USB audio output and Optical digital output are great solutions for many people. Both of these involve feeding the digital audio output from your Mac into a separate Digital to Analogue converter (DAC), for playback through your sound system.
The quality of DAC's varies wildly, so we would recommend trying a few to ensure you find the DAC that suits you best. With the correct DAC and setup, this is the best quality way to get sound from your Mac. Note that the optical audio output is combined with the headphone jack, so you need a mini TosLink adaptor for the optical output to work. There are a couple of things to be careful of though.
Apple and iTunes in particular does some pretty strange things when it comes to sample rate and bit depth conversion, more on this a bit later.
Using bluetooth is extremely convenient, however it makes a few compromises along the way. Bluetooth is a short range protocol, so only really works when you're in the same room as the receiver. Another problem with Bluetooth is artifacting, where random packets of noise will be inserted into the sound when conditions aren't perfect.
Recent model Mac's (as of 10.6.5) fully support apt-x bluetooth which is nominally CD quality. However, it can drop down to standard bluetooth if conditions mean the bandwidth isn't available. Again, the quality of bluetooth receivers varies, with the best option usually being one with a digital audio output, allowing you to connect to an external DAC. It is also worth nothing that standard bluetooth has a latency of about 150ms, which can be too much when watching movies or video.
AirPlay is another convenient method which makes a few compromises. When played between two devices hard wired into your network it is relatively stable, however, when you introduce slightly wi-fi into the equation it can become a little troublesome, with dropout not being uncommon. Another quirk is that Apple TV changes the sampling rate of everything to 48kHz (CD's should be 44.1kHz, DVD's 48kHz), which results in it not being the best quality option either.
Streaming your music to a network player is yet another option. When done correctly this can be one of the best quality options. This sort of streaming isn't limited to Apple and works in the exact same way for Windows or Linux devices. One of the best things about this method is that there are very few quirks, and typically sampling rate and bit depth will be selected automatically, meaning no difficult set up or weird sound issues.
Format Support, Sample rate and Bit Depth Add-on's
iTunes is a notoriously closed off environment. Although it supports its own proprietary lossless format (ALAC) it doesn't support the popular FLAC format. There are a couple options to resolve this problem.
Playing back through a player such as VLC means you can play just about anything, but it is nowhere near as easy to organise as iTunes. Another option is to convert FLAC to ALAC using a decent converter such as XLD, however this doubles up on files and can require a bit of setup. The third and nicest option is to use a third party add on such as PureMusic, Decibel or Audivarna these products allow you to use iTunes to manage and "play" your music, but output the sound separately to the software in your Mac. These addons also happen to solve all of Mac's sample rate / bit depth issues. However, none of them are free. 6moons has a detailed comparison of these three products here: 6moons.com
One of the quirkiest things about digital audio in OSX is the way that it handles bit depth and sampling rate conversions. Bit depth is the accuracy of each digital slice of music and the sampling rate is the number of these slices per second. By default it will not change these based on the source material. So if it's set to output at 192kHz for example and the source is 48kHz it can sound terrible. The issue is solved by the third party add on's mentioned above, however the sampling rate and bit depth output can be adjusted in: Applications > Utilities > Midi Audio Utility.
There are many popular options for getting better sound from your computer, however some are superior to others. A couple of our recommended set ups are:
iTunes > Audivarna > USB / Optical output > DAC > Stereo
Networked Storage > Network > Network Audio Streamer > Stereo
iTunes > Bluetooth > DAC > Stereo
Third Party Addons: http://www.6moons.com/audioreviews/players/4.html
High Resolution Music: https://support.apple.com/en-us/HT202730