The Digital Journey: Assembling a Computer-Based Music Server for Dummies

RBFC

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I'll get the important part out of the way immediately. The "Dummies" in the thread title refers mainly to me.

So, here we go.

It was a dark and stormy night. Bathed in the glow of the LEDs that adorn my audio equipment, I sat, then rose, then sat, then rose...... changing CDs during a listening session. At first, I thought it was the sign of a small stroke. Then, I realized that iIwas OK.... That strange tingling in my head wasn't harmful. I had just gotten an IDEA! I'd read and heard about this "new" way of playing all this digital music. All you needed was a computer and a way to hook it up to your audio system. Now, it all sounds so simple........

For someone who had easily configured an analog system with 4 Krell monoblocks, active crossovers, and full-range big Apogees, for someone who had assembled an oil-less compressor system that fed a regulator to operate his air-bearing tonearm located one floor away, surely this computer audio thing can't be too hard. As Bill Cosby (as Noah) so famously said, RIGHT!

After reading about J River Music, Drobo (is that a new superhero?), and more acronyms than the US Army (USB, SPDIF, ASIO...... ad infinatum), I began to think I'd better ask some questions.

Well, I asked those questions. "What do I need to set up one of these computer-based music servers?" or How do I get the music from the computer to the audio system with the highest fidelity?" and other similar queries. I asked lots of folks, several of them quite well-known in audio/computer audio circles.

After receiving virtually the same answer several times, Just get a computer, a DAC, an external drive, and you're good to go!", I got very frustrated. I first blamed all these individuals for being vague with their answers and not really getting down to details that I would need in order to actually get this think working. I later realized the error of this line of thinking.

CHAPTER 1: THE COMPUTER

Since I was familiar with MacIntosh computers from over a decade of exclusive use, it seemed a natural choice to stick with Mac for my music server foundation. Of course, I was actually functional on a Mac computer at a pre-school level, barely able to navigate through iTunes or able to rip a CD and produce a copy. Reading about all the setup details and deleterious background processes that degrade sound quality, I got even more confused and intimidated.

I then looked at all-in-one devices like the Olive HD. Although attractive from an "idiot-proof" aspect, I soon learned the limitations of these dedicated music server devices. So, it was back to figuring out how to get a MacIntosh computer to do all this correctly for me.

Then, I ran across Mach2 Music. They offered a Mac Mini computer that had all the setup details already performed for you. They had pre-loaded ripping software, and several music player software choices already on the machine for you to sample, then choose what you preferred. They wrote scripts that optimized the performance of each of these music players, and also installed scripts that would accomplish desirable configuration options such as turning off "Spotlight" on your Mac. These special setup scripts reduced the load on the computer, so that it ran "quieter" while playing music. They eliminated some of the other programs on the computer, so that it really was primarily intended for music playback.

As fate would have it, Mach2 Music is located in my hometown. I got in contact with them, and their President of Sales, Kevin Burke, offered to bring one of their Mac Mini computer servers over for an audition. My goals had been realized. (I already posted a short review of the Mach2 Music Mac Mini in the Computer Music Server forum here.) This pre-configured computer solved many of the start-up dilemmas I faced, real or imaginary. Plus, it sounded great. Kevin Burke and his business partner, Darrell McCombs, are class acts. After talking with Kevin, I finally began to understand the details about computer audio that had eluded me.

Not only did I purchase the Mach2 Music Mac Mini from them, I also got a 2TB hard drive and a special FireWire cable that had the power lead disconnected. Since the hard drive used a wall plug, it was unnecessary to have power running through the FireWire cable; a process that is thought to add noise to the signal.

So, I had the computer, the storage, and the means to connect them. Now, how the heck do I get any music out of this thing into my system?
 

RBFC

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So, I now had the computer parts and a rudimentary idea of how to use them. I borrowed a coaxial digital cable from my dealer, a Purist Audio 2 meter model. I then borrowed an M2Tech HiFace USB>SPDIF converter, so that I could use the USB port on my Mach2 Music Mac Mini to feed the coaxial inputs on my Krell S-1200 preamp/processor. Armed with a couple of albums that I had loaded onto the Oyen external hard drive, I got ready to try this thing out. I should mention that Mach2 Music had already configured the external drive and named it, etc., so that it was also plug&play easy.

I really wanted to use the DACs in my Krell S-1200, seeing as they're the new ESS Sabre 32 bit models that have become fairly popular at the moment. I didn't see the need to shell out more $$$ for a separate DAC just for the computer. So, I researched methods to get music signal out of the computer and into the audio system via a "direct" connection. That's why I chose the HiFace and coaxial cable to try. The Mac Mini also has an HDMI port, fully 8-channel 24/192 capable.... more on that later.

Well, these first listening tests went pretty well, all things considered. I played files ranging from standard redbook up to 24/192 Chesky material from their DVD-R releases. The redbook stuff sounded pretty good, but still a bit harsh. 24/96 sounded better, as you would expect, but still not exactly "right". The 24/192 wouldn't play at all.... I later discovered that the Krell wouldn't accept 24/192 via its coaxial inputs (they are releasing updates to correct this). It turns out that the M2Tech HiFace runs slightly "hot", exceeding the SPDIF spec by about double in output voltage. While this excess wouldn't damage my Krell, it produced a very high gain and the resulting issues with volume settings. Also, the SPDIF connection carries more jitter than USB, and the slight harshness in the sound might be attributed to this as well. But, for $150 for the HiFace and ~$300 for the coaxial cable, the sound wasn't unexpectedly terrible. I should comment that the sound was still better than playing CDs from my Denon 3800 Blu-ray player into the Krell. It just wasn't quite all "there" yet.

Seeing as I wanted to be able to play 24/176.4 (Reference Recordings and newer Chesky files) and 24/192 (Chesky, Linn, 2L, etc.), I wasn't satisfied. I was upset with the Krell, as it didn't support these resolutions via its coaxial inputs. I was upset with the HiFace, since its out-of-spec output voltage gave a bit of harshness to the sound of redbook. So, I decided that I may have to look at using a separate DAC after all.

Then, I remembered that the HDMI port on the Mac Mini may be another possibility for playing all the resolutions I hoped for. I hooked up an HDMI cable from the Mach2 Music Mac Mini to the Krell S-1200 and began the testing. First, I immediately noticed in the Audio MIDI panel of the Mac that the HDMI was limited to only 16/44.1 resolution. Other resolutions were "grayed out", meaning that the Krell wouldn't support higher resolution than this via the HDMI input. Weird, since I had played 2L's Divertimenti in full 24/192 through my Blu-ray player into the Krell, and 192 kHz displayed on my TV monitor while it played. So, it turned out that the software in the Krell was not set up to handshake with the MacIntosh computer. (The folks at Krell are PC-based). My dealer currently is testing the software update Krell issued to allow proper Mac handshaking and full 24/192 resolution via HDMI. The sound of the redbook HDMI connection was not as good as that with the HiFace/coaxial setup anyway, so I abandoned this avenue of thinking.

So, although I was disappointed with Krell for having these issues, I had to come to understand a few things about digital audio and computers. Krell has long been a technological leader and extremely reliable manufacturer of electronics. However, their entrance into the Home Theater/surround sound/HDMI world was no easier for them than for any other high-end company. The number of issues involved in proper implementation of all this digital communication is enormous. So, I have no grudge with Krell, especially since they're working on the updates to correct these problems.

Therefore, I was left with the option of getting a separate DAC for the computer server. Since the Krell has extremely well-implemented balanced analog circuitry, I wanted to use a DAC that offered true differential balanced XLR analog outputs. The Weiss units offer this feature, but I really wanted to stay under $2000 for my "entry" DAC (knowing that DSD-capable units are just down the road & already here with Playback Designs). I was reading around the net and saw the Calyx Audio DAC24/192. ( www.calyxaudio.com ) Priced at $1500 USD and manufactured by Digital and Analog Company in South Korea, it had received a very favorable review that compared it to the Weiss DAC202. While I had some reservations at first about a "new" offering from a relatively unknown company, I began a series of email chats with them. I was immediately impressed with their promptness of response and thoroughness to their answers. It turns out that they are large-scale IC chip manufacturers and decided to enter the high-end audio arena. After satisfying myself that these folks were serious and would handle any problems honorably, I ordered my DAC from them.

Shipped via International Express Mail, my DAC arrived in about one week. Thus began the next segment of this saga, and unbeknownst to me, my digital journey was just warming up.

Lee
 
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RBFC

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CHAPTER 2: DAC AND MUSIC PLAYER SOFTWARE

Upon receipt of the Calyx Audio DAC24/192, I installed it into the system using a USB cable by Most Beautiful Sound, which is sold by Mach2 Music. Graciously on loan, I was glad to have a high-quality cable (1m length) on hand to complete the hookup. Using a borrowed pair of 2m Purist Audio Museaus XLR interconnects, I had the music server all hooked up to my system.

*Please note: I will review the Calyx Audio DAC24/192 separately, except for when necessary to the discussion at hand.

I started by playing a few redbook CD files that we had already loaded onto the Oyen external hard drive, encapsulated in a DataTale enclosure. I used a special FireWire cable from Most Beautiful Sound that had the power lead cut so that no power could flow through the cable, only the file data. Since the DataTale has a regular 120V household plug, the lack of FireWire power was not an issue.

I began by using the Amarra player software (www.amarra.com) and the sound was mesmerizing. Now I understood what folks had been raving about when discussing computer audio. The background was absolutely black, and instruments leapt out of the darkness, exhibiting more of their natural tonal color than I've experienced before. (Understand I've never heard a DCS stack or the equivalent). I thought we had it made.....

Next, it was time to check out some high-resolution material. After all, that's one of the big drawing cards of computer audio these days! So, I cued up one of the Chesky DVD-R renditions of Jazz Side of the Moon in 24/192. The sound was unbelievable! Then, about 30 seconds into the first track, there entered the first of a random series of "ticks" in the playback. I tried playing the file over again, and the ticking remained..... but in different spots than the last time! Now, we're not talking about having Alvin and the Chipmunks on my system, but about 5 - 20 ticks per song that sure sounded like digital "read" errors when playing CDs. So, I tried other 24/192 files, both in .wav and FLAC from 2L and Chesky. All of the high-res files caused the ticking.

I then tried PureMusic, another music player software. Fortunately, the Mach2 Music Mac Mini had come with scripts for several music players already installed, so that I could audition and choose which player I wanted to use. Using PureMusic, there was unfortunately no difference. The same difficulties occurred with iTunes (.wav only, of course). So, after a frantic series of emails with the manufacturer and the kind folks at Mach2 Music, I was considering what to do next. As a member of WBF, I am fortunate (along with all of you) to have Amir as a resource. After relating the story to him, he told me that the DAC was broken. Then, an interesting thing happened....

I downloaded the free music player Audirvana ( http://code.google.com/p/audirvana/ ). I tried playing the high-res stuff with Audirvana and IT ALL WORKED WITHOUT TICKING! So, there was obviously a more convoluted, diabolical scheme behind all this misery.

Amir quickly brought me back to Earth, telling me that different music players send their data in different ways. So, it appeared that the DAC could handle what Audirvana was sending. However, the inability of the DAC to work correctly with iTunes was the major flag. iTunes is known to be extremely bug-free as a player, and if the DAC wouldn't work with iTunes, it was still broken.

So, I contacted Seungmok Yi, of Digital and Analog, and demanded that I either receive a DAC that worked properly or get a refund. Mr. Yi was extremely courteous and professional. He had actually bought a Mac Mini in order to test their DAC under the exact configuration I was using, so that he could duplicate the problems! He immediately offered to send a replacement PCB board for the DAC which contained all the clock circuitry, etc. I was assured that replacement was an easy "remove the cover and plug in the new board" process, with no soldering necessary. I received the new board in 6 days (excellent from Korea!) and GET THIS was able to replace the board in about 15 minutes without difficulty. I instantly went to the store and bought a pocket protector and some hornrim glasses.

The new PCB board was ready to go. I first cued up one of the troublesome 24/192 files and started the Amarra playback.

STILL TICKING!!! **#@&**%#$@!!**

Once my blood pressure was back to levels compatible with life, I thought, "What the hell, let's try iTunes." iTunes played the files without a single flaw! Now, figuring I was dying as the warm glow of enlightenment swept over me, I figured that I would try PureMusic too. PureMusic also played the files without a single tick!

So, I then realized fully that this computer audio thing was going to be something much harder to comprehend than virtually any analog problem I had ever faced.

I fired off another PM to Amir (who should have had me on "ignore" by now). He responded in his usual efficient, gentlemanly manner and cited a thread at www.computeraudiophile.com that discussed ticking problems with the Amarra playback software. I read the thread and attempted to perform some of the suggested "fixes" for the ticking.

First, it was suggested that the "screen sharing" application of the Mac Mini used too much CPU when active and left insufficient amounts for the playback software. I opened the Activity Monitor, which showed CPU usage both in percentages and graphically. With screen sharing engaged to my MacBook Pro (my method of controlling this whole mess), there was virtually no CPU load of significance. (DID I MENTION THAT I WAS LEARNING MORE ABOUT MY MAC COMPUTER DURING THIS TIME THAN AT ANY OTHER TIME IN THE LAST DECADE?) So, the screen sharing "hogging" the CPU was out. Another suggestion was that the player window and the playlist window both required substantial amounts of CPU when open and running. Amarra has an active signal level metering function on the display. So, I minimized the player control window and the playlist window after starting playback of a 24/192 file. There was NO ticking! It's about now that I thought the heavens were going to open up, because I had fought this battle for 2 months. The Activity Monitor confirmed that by minimizing the 2 Amarra windows, this change reduced the CPU usage to 1/8 of what it was with them open! So, the use of CPU with the windows open occasionally became a bit too much for smooth operation, and caused the ticking.

Further experimentation showed that Amarra was using 20 - 30 times the amount of CPU that Audirvana used. With the Amarra windows minimized, usage was only about 3 - 4 times that of Audirvana.

I finally had a system that was functioning without audible bugs, and much of the delay in solving the problem was in my own ignorance about digital audio systems and computer usage. Remember the first sentence above, where I spoke of myself being the dummy? Well, I proved that to be quite true. But, I'm not quite as much of a dummy today, thanks to Amir, WBF, and a lot of hard work.

Lee
 
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RBFC

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I'll add that the sound is absolutely glorious. As stated previously, I'll put up a separate review of the Calyx Audio DAC24/192 as soon as I get the time. I've got to spend a little bit of time doing this heart surgery thing so that I can pay for all this stuff.

Lee
 
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amirm

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What a great story Lee. Thanks for writing up your experiences. I was only privy to part of it as we went back and forth.

Now, are you sitting down? Because I have something to add to your story.

A few days ago, I finally got my hands on an evaluation unit of the new PeachTree iDac. I plugged it into my high-performance core i7 workstation and wouldn't you know, it ticks here and there too!!! Problem is, my CPU usage hovers between 0% and 1% so the medicine I gave you, does not work for me. So the long journey starts for me to figure out what is going on here. PeachTree is expectedly saying it is my PC and the thing works fine.

I need to narrow the problem down as I think it only does it when I first open the device. But haven't had time to troubleshoot.

Expanding a bit on the general issue, playing audio is a real-time thing. There must always be enough samples to play or else, the DAC "under-runs" meaning it will run out of things to play. Some DACs will then softly ramp down to nothing. Others, just stop playing and start again when they get the next sample and in between they either play zero or the last sample. Problem with this is that you create a square wave representing the gap. And a square wave as infinite bandwidth and hence the static click we hear.

To avoid the problem, there is usually some amount of buffer memory in the DAC just in case the PC falls behind and doesn't feed it data. This was the cause of the problem for Lee. His CPU was too busy to service the audio device. In my case, it seems more complex. although even in the presence of ample CPU, it is still possible to not hear a message ("interrupt") from the device asking for data.
 

RBFC

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I'm sorry to hear that, Amir. Are there any buffer adjustments possible in the Peachtree? If you can let it fill up "more" before playing, you may circumvent these issues.

Now, that's funny.... me giving Amir advice on matters digital....

Lee
 

Mobiusman

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Lee,

Thanks for sharing your tale. One thing that is not clear to me is are you now using the Audirvana music player and if so, are you using purely as the playback component much like Amarra is used. I would love to hear your take on how it interfaces with your music library. Also, which version did you download? I am using a similar setup to you with a Macmini, connected via miniToslink to a Bryston BDA-1 DAC, which is connected balanced to my balanced preamp. BTW, I get my video signal to my plasma using a Apple mini video-DVI adapter to my plasma DVI input which is just about akin to a regular monitor, which a touch less brightness, but much more than when I used a USB-HDMI adapter.
 

RBFC

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I'm using the Amarra player. Here we go... I think it sounds better than the others. Better reproduction of instrumental tone, more realistic human voice, etc. in my system. Audirvana sounds thinner, more "sterile" to me.

As to interfacing with music library, the players both have "add" functions where you can browse your computer for the files you wish to play. In my situation, I rarely get more than one hour to listen to music uninterrupted. So, the utility of lengthy playlists is little for me. I simply play single tracks (or symphonic movements, etc.) or form a short playlist by browsing through my external drive. You may already be familiar with how these players work, and I am using them on a rudimentary level that suits my needs just fine.

If this didn't answer your question, be more specific and I'll be happy to help.

Lee
 

RBFC

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There were two separate issues. First, there was a defect in the circuit board of my DAC. This problem made iTunes and PureMusic tick, along with Amarra ticking too. I replaced the PCB, and the ticking stopped with iTunes and PureMusic players. Amarra, however, had its own separate issue that related to CPU usage while its window displays were active. These displays use a large amount of CPU power. Amarra has actually announced an update, to be released Friday at AXPONA, that uses 1/3 less CPU among other changes.

Lee
 

Seta

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The thing about Mac/PC + software based music servers - they're never really plug-and-play.
Something like a Squeezebox, Bryston BDP-1 or the new Auraliti makes life much easier. But hey, where's the fun in that?

Lee,
Would love to hear what you think of the Calyx DAC.
I recently tried the Calyx with an outboard power supply (Kingrex), and found it to be beneficial. You might want to give it a try.
 

Vincent Kars

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Amarra has actually announced an update, to be released Friday at AXPONA, that uses 1/3 less CPU among other changes.
I must admit I do think there is a strange paradox going on.

The Mach is a Mac optimized so probably disabling all that is not needed to play audio.
Minimizing system load is a common approach to improve sound quality (reducing jitter)
Amarra uses a hell of a lot of CPU, exactly the opposite of this approach.
Do other players sound 'thin' or do they sound more 'transparent'?
 

RBFC

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I must admit I do think there is a strange paradox going on.

The Mach is a Mac optimized so probably disabling all that is not needed to play audio.
Minimizing system load is a common approach to improve sound quality (reducing jitter)
Amarra uses a hell of a lot of CPU, exactly the opposite of this approach.
Do other players sound 'thin' or do they sound more 'transparent'?

To me, they've sounded harmonically thin or incomplete. Human voice is a good example.

Lee
 

Phelonious Ponk

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The thing about Mac/PC + software based music servers - they're never really plug-and-play.
Something like a Squeezebox, Bryston BDP-1 or the new Auraliti makes life much easier. But hey, where's the fun in that?

iTunes is plug and play. Millions of people play it off of their computers, phones and portable players every day without any of the issues that seem to plague other players. And while I agree with Vincent that the opposite approaches taken by The Mach and Amarra seem to work against each other, system load is not a problem on Mac systems running iTunes either. Good galvanic isolation, good jitter reduction at the DAC, possibly re-clocking outside the computer in extreme cases, should address the jitter and noise issues with no need to resort to programs which seem to be beta testing for years on paying customers.

Tim
 

RBFC

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The Amarra player uses most of its CPU load by producing the "meter" display. I still just minimize the player windows once I'm underway and the sound is great. Believe me, I was ready to dump Amarra back onto my dealer before I fixed the ticking, but was bummed about it because I felt Amarra sounded better. I tried Audirvana in "Integer Mode" and wanted to like it better (it's free), but it just didn't sound the same to me.

Tim, I agree about the home-beta-testing-for -$$$ approach. I've exchanged some heated comms with Sonic Studio over this issue and I know they're working on this constantly. The new version reduced CPU load by 30-40%, with more hopefully coming soon.

Lee
 

Seta

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Dec 7, 2010
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iTunes is plug and play. Millions of people play it off of their computers, phones and portable players every day without any of the issues that seem to plague other players...

Tim

That is also true. But for iTunes you still have to go to AudioMidi and select the correct sampling rate and bit depth each time you move from red book to a high resolution file. There are of course softwares that do that automatically, such as Amarra and the likes, but they do have issues. To get the best digital output out of a Mac (included toslink are considered inferior), you need to think about various USB/SPDIF converters. Some native, some need drivers hence bugs etc. Have not started on Windows yet.

Not saying I don't love the mac. Running two headless mac minis in two rooms.
 

Orb

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Hey Lee,
does the ticking occur for both USB and firewire?
Appreciate you worked out most of the problems but curious if you had same experience with the firewire, technically streaming USB utilising CPU cycles while firewire does not in the same way.
Not saying that this is the problem but worth testing both interfaces if at all possible.

Thanks
Orb
 

RBFC

WBF Founding Member
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Hey Lee,
does the ticking occur for both USB and firewire?
Appreciate you worked out most of the problems but curious if you had same experience with the firewire, technically streaming USB utilising CPU cycles while firewire does not in the same way.
Not saying that this is the problem but worth testing both interfaces if at all possible.

Thanks
Orb


I don't have a FireWire DAC, so I can't answer your question. Seeing that the CPU activity changed so dramatically by merely minimizing the player's display windows, I must believe that this draw on the CPU was the main culprit in the ticking.

If I get lucky and someone brings a Weiss, etc. by the house, I'll be sure to report!

Lee
 

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