Sunday, November 9, 2008

Audiophile Reference Music Servers

I began the music server series here on Computer Audiophile with some very basic systems. These music servers were great solutions for readers looking to get in the game or upgrade an existing starter system. One of the problems with this approach was that readers often wanted more. I received countless emails from readers, manufacturers, and dealers asking what parts of these music servers I would upgrade to accomplish a specific goal. I have literally spent months testing different DACs, interfaces, operating systems, storage solutions etc... I've also been working with some very highly respected people in the high end audio & music industry comparing notes about sound quality, library functionality, file formats, and everything else under the sun. All of this work continues and I can promise you some very big things are in store for computer audiophiles. Right now there are a couple solutions that I, and others, consider reference quality. These music servers sound better than almost any traditional transport/DAC solution available today. What's more, while increasing sound quality and taking convenience to a whole new level you can save tens of thousands of dollars in the process.

Let me start by saying these two reference music servers are certainly not the only servers capable of obtaining audiophile sound quality. There are many different ways to reach the end goal, especially when we all have different end goals. If you are looking for the best sound available today from a computer based music server I highly recommend you start here.

Reference Audiophile Music Server (Windows XP)

Some friends and associates of mine in the audio industry have settled on this music server as their current reference. These people could have any music server they want but choose this one over all others. In fact it is beneficial for them to have the best sounding server available today. If you're a Windows fan take note.

This reference server is based on Windows XP. The bottom line for choosing XP over Vista is sound quality. There are issues to work around with both operating system and in my opinion both are capable of great sound. But, a reference system is built for sound and right now Windows XP (as opposed to Vista) is where it's at. According to some in the industry nothing else can touch the sound quality of a properly configured Windows XP music server. Not even a Mac. I'm not willing to make that leap just yet. I am however conducting extensive testing with Vista Ultimate 64 bit and hope to come up with another reference quality music server.

The music playback application of choice right now is MediaMonkey. I am a fan of a few others like JRiver and Winamp, but since this is a reference music server I'm going with MediaMonkey. Since this is Windows XP the KMixer must be avoided at all costs. Currently the best sound is obtained by using the MediaMonkey output plugin called waveOut (out_wave.dll). This bypasses the KMixer and allows audio to be sent directly to the sound card. Under certain circumstances ASIO output v0.67 SSE2 [out_asio(dll).dll] must be used, but it does not sound as good as waveOut. Once circumstance where ASIO output v0.67 is required is with playback of multi-channel DVD-Audio rips that have been merged into one file. Both of these plugins have minor configuration options. The most important options is to select the proper output hardware device.

One of the most important components of a reference quality music server is the digital I/O. Right now nothing beats the Lynx AES cards. In this Windows XP based server the card to use is the AES16 PCI version with legacy drivers and legacy firmware. This combination simply sounds the best. It would be very nice to use the current drivers and firmware, but not to the detriment of the sound quality.

Connecting the Lynx card to the DAC is done by either one of two cables. Lynx manufacturers an HD26 pin to AES breakout cable that has 8 channels and external clock wires. My preference is a specially made HD26 pin to a single AES (XLR) termination cable. Since the DAC only has one AES input this is very nice. Removing the extra seven "antennae" can't be a bad thing.

Technically this DAC is not part of the music server, but I think it is such a critical part of a reference music server system that I'd be doing a disservice not to recommend it. The Berkeley Audio Design Alpha DAC is the current reference music server DAC of choice. Not only is this DAC an unbelievable performer, it has one feature that is critical to music servers. This DAC can has an indicator that illuminates when the music server is passing a bit perfect stream to the device. This indicator does have limits, but it is all you need to guarantee the music server is setup correctly. The indicator only works with HDCD recordings and illuminates when an HDCD recording is played back bit perfect. Fortunately this is all that's needed. As long as one song is bit perfect and no changes are made, the rest of them will be bit perfect (assuming all is well with the track). This DAC is capable of up to 24/192 and has a volume control. This allows listeners without analog devices to remove their preamp from the audio chain. Removing the preamp and one set of interconnects is a good thing in almost all situations.

As with everything in life, nothing comes without a price or possible pitfall. This music server does have the capability to produce white noise that will blow every tweeter connected to the amp. In a limited set of circumstances the music server will lose clock and spit out this white noise. Some events know to cause this problem are adjusting the buffer settings in MediaMonkey while playing back music. Another possible problem can arise when changing the name of the currently playing track. This often causes a stutter in the playback, but can lead to loss of clock -> white noise -> blown tweeters. To me this is a scenario that is self inflicted and can be avoided 99.999% of the time. When listening to music don't make changes. I have yet to hear of any problems when changes are made at the appropriate time. This is certainly no guarantee but I'd be 100% comfortable using this reference music server keeping in mind the information provided here.


Windows XP Reference Music Server

- OS - Windows XP Professional ($270 @
- Computer hardware - Intel based ($1,500 to $10,000+ depending on customization)
- Music App - MediaMonkey Gold ($20)
- Output Plugin - waveOut (out_wave.dll)
- Digital I/O - Lynx AES16 (PCI version) (~$700)
- Legacy drivers and firmware
- DAC - Berkeley Audio Design Alpha DAC ($~5,000)



Reference Audiophile Music Server (OS X)

Most Computer Audiophile readers know I am a big supporter of Macs and OS X. It follows that this reference music server is identical to the one in my system that I use for every component review.

I like OS X because it is bit perfect straight out of the gate. Bit perfect playback is far from the equivalent of great reference sound, but iTunes is the standard by which all current OS X applications are judged. iTunes is not perfect all around because of issues like lack of auto sample rate recognition and a limited number of supported file formats, but it is the OS X reference. Personally I've never heard better sound than the Reference Recordings HRx 24/176.4 albums played back on OS X.

There are a few hardware options available from Apple, but only one can be part of this reference system. The Mac pro is the only Mac capable of accepting a PCIs card without less than optimal add-on external hardware solutions. My reference Mac Pro music server has eight Intel Xeon CPU cores (2 CPUs x 4 cores) and ten GB of memory. I limit the internal disk to one drive. This limits heat which limits fan speed and noise generated from the fans. I did not mention disk storage in the Windows reference server section, so I will cover the topic briefly here. In my opinion the ideal reference storage for a music server is the Thecus 5200B Pro. This NAS device has a huge disk capacity, a ton of configuration options and is powered by an Intel processor. Since we are talking about reference music servers sound quality is paramount. This NAS unit has Gigabit Ethernet and can be places in another room out of ear-shot from your listening room. No matter how quiet a different disk solution is, if it's in the listening room it's not as quiet as the Thecus 5200B Pro.

As mentioned above iTunes is the OS X application of choice. Simply stated, I have yet to use something on OS X that has better sound quality and better design. Note: I am aware of something coming out toward the end of the year that may change the game for iTunes on OS X. I have to leave it at that for now :-)

Digital I/O on the Mac Pro reference music server is accomplished through the Lynx AES16e PCI-Express card. This is the newest version of the AES16 card used in the Windows XP reference server. The notable difference in configuration is that I use the most current drivers and firmware for the AES16e. I haven't heard a sonic advantage to older drivers or firmware like the advantage heard with this combination and the AES16 PCi card on Windows XP. The Lynx card is really a fabulous way to get the digital stream to the DAC. This card I have seen jitter measurements for this card at under 20 picoseconds. The card also handles sample rates up to 24/192 allowing Mac users to skip the limitation of the built-in optical output and the 24/96 limitation of current USB connections. FireWire is definitely another way to output 24/192 music streams from a Mac. Since this is a reference music server I chose the AES16e as my digital I/O method connected to the DAC via HD26 pin to AES (XLR).

Again the DAC I use is the Berkeley Audio Design Alpha DAC. It really is the reference music server DAC for all the reasons mentioned previously. There are certainly other capable DACs that accept AES, but I am willing to put the Alpha DAC up against almost any of them. The creators of the Alpha DAC are some of the most respected people in high-end audio. These guys founded Pacific Microsonics and HDCD. In my conversations with Berkeley Audio Design I learned just how much R&D went into creating this DAC. It is truly unbelievable. Plus these guys thought of everything in terms of usability. When the volume on the DAC is muted, it does not un-mute when you turn the volume down. Only when you manually un-mute the DAC or turn the volume up does the sound once again come out. This may seem like a simple and obvious feature, but I assure you it's not. Check the components in your system to see if this simple and obvious feature has been implemented.


OS X Reference Music Server

- OS - OS X ($0, included with hardware)
- Computer hardware - Mac Pro ($2,299 to $10,000+, Reference Music Server ~$3,300)
- Music App - iTunes ($0)
- Digital I/O - Lynx AES16e (PCI-Express version) (~$700)
- DAC - Berkeley Audio Design Alpha DAC ($~5,000)




There you have it, two reference audiophile music servers. There are many more details I could go into for each and every piece of these two servers. For example configuring applications to rip bit perfect files, preferred file formats, and customizing each server for silent operation and removing the moving parts for complete solid state operation. As I said earlier there are other ways to achieve reference grade sound quality. I've decided on these two systems after more research than I care to admit. There is no doubt that Windows and OS X are fully capable of producing reference quality sound. One operating system may be a little easier to configure, while some say the other OS sounds better. The fact that both properly configured systems reproduce music better than almost every traditional transport/DAC solution is great for computer audiophiles. I'm not sure there has every been a time as exciting as this in the history of high-end audio.