Ok Folks, here we go... my attempt at a series of posts on how to choose and configure a
Mac Mini for use as a music server.
First, a bit about my basic philosophy as it regards music, audio, and just about everything
else: I like to keep things as simple as possible but not overly simple, and I have fairly
high standards as far as playback quality is conncerned, so take this for what it's worth --
yours may be higher, lower, or just plain different, which is fine and to be expected, so
not necessarily all of the things I suggest are going to work universally and I simply
cannot guarantee that you will hear the same things or perceive the same amount of change
that I do or did when I made these choices. I also don't have any hands-on experience
beyond the mid 2010 mac mini, but I have two of those (1 mostly stock and the other taken
pretty close to the extreme). On the other hand I will pass along the anecdotal experiences
of others I know and whose ears I trust when it comes to some alternative considerations of
methods, devices, platforms, etc. This field is changing very rapidly in some ways and in
others, not as quickly, so there is always bound to be new information, software and
discoveries around the corner. The one great thing about using a computer is that often
changes can be made incrementally and often with software, so you should be able to stay on
or close to the leading edge as you wish.
Ok, so why the Mac Mini, and specifically why the mid 2010 and 2011 unibody aluminum Mac
Minis and not MacBook/MacBook Pros, iMacs, MacBook Airs, etc. (or windows based computers
for that matter)? In short, I don't know, and I'm not sure anybody else really does either,
but it has something to do with power consumption, perhaps the RFI shielding of the body,
the layout of the motherboard, the parts chosen, the power supply, the operating system,
etc. but most likely some sort of confluence of all these things and more. What has become
apparent with all of this is that the more you turn off in terms of hardware, reduce in
terms of processing, and simplify, the better it sounds. In general I'm also speaking about
running the mini as a dedicated music server and generally headless (no keyboard, mouse, or
display). Notebooks tend to have a lot of stuff crammed into an even smaller space, have
high voltage dc-to-dc converters on board to supply the voltage needed for displays, and are
generally built for ultimate compactness, not lowest noise. Likewise with desktops and
iMacs, etc. -- there's no way to really get too far from the display noise and power
supplies, etc. Of course a lot of this is really just logical speculation, but the results
keep coming back that the Minis just work best for audio, and that's the best answer I can
give to all of this.
So then, why the mid 2010 and 2011 Minis? The earlier Minis had external power brick power
supplies, which those of used to power supplies in audio things, generally think of as
better -- having the supply away from the active circuitry. I again have to say that nobody
is really sure why the newer minis with the onboard switching power supplies are quieter and
better audio performers than the externally powered ones, but any number of friends who have
made the change to the newer models from the older ones say this is undeniably true -- I
don't know this from personal experience. As for me, I'm all for it -- less boxes, less
clutter, fewer cables, etc. all works for me, and if it sounds better, all the better. Of
course it could all be that it's a matter of better board design, better internal
components, lower overall power consumption, the aluminum unibody, etc. -- again, not going
to guess, just going to be blissfully ignorant and content with the better sound. BTW, if
your 2008 or 2009 mini sounds fine to you, then so be it -- I am not telling you to run out
and ditch it for a new one, but just about everybody I know who has done that has found
improvement, and often very significant.
Of course the mid-2010s are out of production, but you can still find them used -- even
sometimes from Apple in their refurbished products listings -- and these can be a great
deal. The 2011 is interesting in that even in stock form the people who have tried it after
stepping up from the 2010 find it's performance to be slightly better in terms of noise and
ultimate musicality (though some of these differences may diminish as you go further down
the upgrade path). So, perhaps the power supply is different or better, of course there is
no CD drive anymore, and Lion is the operating system (some people have been able to install
Snow Leopard on the 2011, but that is way beyond my current expertise and may only be worth
it in some circumstances.) The 2011 also has a much better TOSLink port with much lower
jitter specs than all other macs, currently or previously, so if you plan to use the mini to
feed an optically connected dac, this may be a good reason to choose the 2011. It is still
speced at 24/96 max, but at this time I believe that to be either a software limitation or a
hardware limitation on the motherboard, but not the transmitter chip. I have confirmed that
this new generation of TOSLink transmitter and receiver chips from Toshiba can indeed handle
24/192 -- this from Jason Stoddard at Schiit Audio. The trick is to get a source capable of
24/192, which are out there, but few and far between at this point. TOSLink has been an
evolving standard and if anybody remembers way back when it came out, it was good for 16bits
at 32 khz and intended mostly for dubbing CDs onto MiniDiscs and other low-end consumer
purposes.
The main disadvantage to Lion is that it does not support integer mode data transfer to a
dac -- it simply is not in the operating system to do so, and perhaps Apple feels that the
new 64-bit internal structure of Core audio make this unnecessary, but as I don't have any
real world experience with it, I can't comment one way or another. Some people have found
this to be a limitation, others have not, and I don't know if this breaks down easily along
lines of whether the dacs used are ones that can take advantage of integer mode or not.
Basically (and I'm speaking of PureMusic as the playback software here, as that is what I
use and know best) integer mode bypasses core audio support, disables dithered volume
control, EQ plug-ins, etc. and is the cleanest path from memory to dac and taking exclusive
control of the specific usb port (there are other ways to do this last bit too.) It does
provide for what I consider to be a significant leap in playback quality, even though I
don't use EQ and dithered volume control normally. Mathematically it's a much faster, less
processor intensive way to get the bits to your dac without the computer being able to
interfere.
Amarra supposedly bypasses core audio to begin with (as best I can tell from their published
literature), but they still maintin a double precision floating point internal data format,
which in turn leads to more processing overhead -- whether this makes any real perceivable
difference in playback quality, I can't say as I've not done the A/B tests (though I will do
so at some point, I'm sure.) Anyway, all of this is discussion on floating point vs integer
formats, core audio, etc. is all to the best of my current understanding and as has been
mostly confirmed by some of the people who write this software, but I make no cclaims as to
it's ultimate technical correctness -- I'm just not there in my deeper understanding of the
Mac and it's operating system. The proof is in the listening.
So, that's enough for now -- in summary, keep things simple as possible, choose the 2010
withSnow Leopard if you wish, the 2011 if you want to run optical to your dac, either should
do nicely, and get as much memory as possible (more on that in the next installment.)
Coming next: memory, hard drives (internal and external) playback software choices and basic
OS tweaks.
Hope this helps some folks,
Jim
