Optimising iTunes

Upfront apologies: Naim does not figure in this post - but I thought I'd share my experiences and looking for any recommendations from those experienced with this matter.

Over the past two weeks, while CDP was in service, I dabbled around with itunes as a source. Initially with airplay via an airport express (analogue out), predictably the sound lacked a lot of everything. I wouldn't even recommend this setup for casual listening while vacuum cleaning. With my system too far from my network router, streaming is not very convenient (spotty wifi) so I tried hooking up the mac to the system directly.

Success #1: As a DAC, I have the HRT Streamer II+, an affordable but high quality async USB streamer that is powered by the USB interface and is recognised natively by OSX. It gets occasional use, but never in the lead role it played over the last two weeks. I hooked it up to the family mac mini, using an audioquest cinnamon USB cable, with the DAC to the amp via old Siltechs leads. Screen sharing via a macbook. It worked out of the box, with the Mac running iTunes. Sound was OKish, nothing special and definitely not worth the expense.

Frustration #1: I thought the smart thing to do was to use to connect the mac to the TV via its HDMI interface. Wrong. The Mac defaults to YCbCr color space, my TV is RGB native, result is a lovely pinkish hue over everything. An evening's googling gave me script to force RGB, which solved this issue. Apple easy? Yes, as long as you're within predefined operating parameters. Anyway, now the Mini could double as movie server.

Frustration #2. My itunes library was on an external 2TB USB drive. It's a bit older, and the USB interface gets dislodged easily, resulting in the need to go into the system, make peace with OSX and reconnect the whole thing. After a night of rearranging files, I switched in the heavy duty Thunderbolt RAID unit, and this resulted in a marked improvement in reliability. Secondary benefit: it's large enough to hold an unlimited amount of films and music.

Success #2. I was not happy with the sound. Next thing was to try various softwares: VLC (sounds good, bit bloated, inconvenient to use), bitperfect (hogs itunes, not a great deal of change to the sound), amarra (definitely has an effect, but sounds like some equalisation is going on in the background), and finally Audirvana Plus. I say finally, because I quite like the improvement that Audirvana brought to the system. I always understood that async USB negates the computer side of things, but from experience, this is just not true.

Frustration #2: My CD player is back, and within the first minute of switch-on made it clear who's king of the rack. It has a persuasive full bodied and detailed sound that the Mac can only dream about. But the mac is in place and I am reluctant to let it go completely, and I have decided to optimise it further, if possible. 

Next step is to try a linear power supply for the DAC. I've heard it some time ago, and thought I could hear a marked improvement. If that doesn't play out, I'd like to audition a few quality DACs. I'm reluctant to convert the Mac's output signal so they need to be USB DACs - Bryston's new BDA2 looks promising, and so does the new HRT Streamer HD. The V1 looks good on paper as well, wonder how it will match up to the big boys.

Is there anything I've missed? Some software or hardware that will allow the mac to become a reference level source? Is it even possible, or is high quality computer music only attained via streaming?

Cheers,

EJ