Dr. AIX's POSTS TECH TALK — 18 May 2014


You want to put together a “computer music” server? There are lots of ways to do it at lots of different cost levels. Today, I’m going to set up a simple high-resolution music server based on a Mac Mini and a Benchmark DAC2 HGC converter and headphones amplifier (it’s really an audiophile standard preamplifier). It will be able to play high-resolution stereo files into an external DAC and then into headphones or speakers.

This is only one way to go of many. I’ve spent most of the morning installing the Digibit “Aria” server card and power supply into my Oppo BDP-105. I’m planning on putting together a video tutorial on the process but I can tell you that it’s a pretty simple procedure and gives you the amazing SonataDB and user interface that makes the Aria server unique. Of course, you can always use the Oppo all by itself as a music server.

I’m also pretty excited about the new HTC One phone that Sprint just sent me…thanks to the involvement of a reader who happens to be a big shot at Sprint. After my visit to Harman Kardon, he chimed in and told me that he managed to convince some other big shots at HK and HTC to work together to create the best sounding Smartphone available. I think I agree…bit I’m still getting used to working in the Android world so give a few days to report on the phone. It uses Clari-Fi technology too…and I want to do a thorough evaluation of that MP3 “enhancement” technology.

So here’s the basis idea for today’s simple server. I want to use my Mac Mini as the brain. Here’s the list of things that you need:

Basic Physical Setup and Connections

1. Mac Mini Computer (includes a mouse and keyboard)
2. Monitor (I will use an HDMI cable to connect the Mac to a 24″ monitor)
3. High-Resolution DAC (I will be using my Benchmark DAC2 HGC)
4. USB cable to connect the Mac Mini to the DAC
5. Playback software (I will be using Amarra)
6. Headphones or Speakers (with amplification)
7. High-resolution audio files (You can download some from this site click here)

Step 1: Set up your hardware. My pattern has always been to arrange the physical components first. This includes the Mac Mini, the Monitor, the keyboard and mouse and the DAC.

Step 2: Connect all components to AC power.

Step 3: Connect the keyboard and mouse to the Mac Mini. This involves plugging the USB output of the mouse to the keyboard and the keyboard then to the Mac Mini CPU (the actual computer).

Step 4: Connect the Mac Mini to the DAC. There are numerous USB outputs from the Mac Mini. Plug a USB cable to one of the open connections and then plug the other end into the USB input of the DAC. In my setup, this requires a cable that has the normal “flat” USB or “Standard Type A” connection for the Mac Mini side and the “standard type B” plug into the DAC.

Power Up and Software Player

Step 5: Start up the computer and log in, if necessary.

Step 6: Plug a set of headphones into the DAC or make other analog connections to your receiver or preamp.

Step 7: Acquire a high-resolution audio player for your Mac Mini. I downloaded the trial version of Amarra from Sonic Studio (you can visit their website and get it immediately by entering your email). There are other players but I highly recommend Amarra…their playback engine is second to none. It’s based on the same professional playback engine in Sound Blade, their high-end mastering software.

Software Configuration

Step 8: Go to the SYSTEM PREFERENCES of the Mac Mini. It has the icon of a few gears. You want to double click on the “sound” choice. This brings up the window shown below:


Figure 1 – This is the sound preferences window.

You want to make sure to select the DAC from the list of available OUTPUTS. Make sure you are changing the OUTPUTS and not the inputs. If you hear the sound coming through the Mac Mini speakers, you’ve messed up this step.

Step 9: The next thing you need to do is make sure your Mac Mini is going to send 96 kHz/24-bit audio out the USB output. This means you have to open the “Audio MIDI Setup” application, which is shown below. Select the DAC, the 96 kHz and 24-bit options for the output. See figure below:


Figure 2 – The Audio MIDI setup application in the Mac Mini preferences.

Step 10: You’re also going to have to configure whatever music player application you decide to use. Of course, you can use iTunes directly using the setup described above but you will get better sound by opting for a specialized playback engine. There are a number of them (I’ll write a post on them in the near future).

For Amarra, it means going into the PREFERENCES and selecting an AUDIO OUTPUT device. They recommend ignoring the Audio MIDI setup mentioned above but I make sure both are targeting the DAC and are operating at 96 kHz/24-bits. Drag the icon of a “clock” adjacent to the DAC…in this case my Benchmark unit. See below:


Figure 3 – The Audio Selection preference screen in Amarra. Make sure the clock is next to your selected DAC.

Playing Back High-Resolution Music

Step 11: Make sure that the DAC is looking at the USB input. Typically, high-end DACs allow you to select from a variety of inputs…you want to make sure that you’re accessing the USB connection. On the Benchmark DAC2, it means pushing a selector button until the blue light is solid and the selector says “U” for USB.

Step 12: I’m going to assume that you’ve loaded up some high-resolution audio. You can get the free files from my FTP site by clicking here or use any files in your iTunes library. Amarra uses the interface of iTunes to catalog and select music. Choose a high-resolution audio track and hit PLAY on the Amarra player.

Step 13: You can now put on your headphones or turn up the preamp level on you’re A/V Receiver and enjoy high-resolution, stereo music.

I’m planning on recording a tutorial video to accompany these server setups. Stay tuned. If you have any question, please fee free to ask them in the comments below.

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About Author


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

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