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What follows is a contribution from Jim Smith, author of Get Better Sound and previously known as the US importer for Avantgarde Acoustic, Audiopax and Zanden Audio. Jim is presently back in the import saddle with The Lars 2 amplifier from Sweden's Engstrøm & Engstrøm. It's fair to say that at heart Jim is an analogue man - vinyl, tubes and hornspeakers. Embracing digital for him had meant Zanden's $40.000 zero-sampling 4-chassis implementation with valves and a top-loading transport with I²S interface and outboard power supplies.

As a system consultant and in-situ voicing expert, Jim routinely travels across the US to improve audiophile systems. This means measurement gear and other tools of the trade. In his suitcase. Including a digital reference. That latter has obviously rather morphed since his far-from-portable Zanden days. Hardcore audiophiles who play in the ultra-performance realms Jim's prior import accounts represented might thus relate in a special way to his conversion to Computer Audio. Now we're getting to the purpose of today's feature.

Owners of his Get Better Sound book—now available also on DVD—have access to what Jim calls Quarter Notes. Those are regular online additions to the book. They take the form of anecdotes from the trenches, new tricks and valuable new insights. They are accessed through his website to keep GBS customers current. As Jim's email recounts, he felt inspired to share the latest installment of QN with our readership. - Ed

Hey Srajan,
In the Quarter Notes Vol. 2, #2, I wrote a bit about Computer Audio. It received by far the greatest number of—and the most interesting responses—that I had ever received from the previous five issues. The issue I just sent out got even more responses! I should mention that there are the usual folks hesitant to try it - or they have too much invested or whatever. And I've even had some who politely disagreed entirely. The good news is that they are at least thinking about it.

From the correspondence I receive, I'd guess that less than half of my readers have even tried Computer Audio. Therefore since you've taken a stance for Computer Audio over the spinning discs, I thought I'd offer this article to you if you think it might stir up more interest for your readers. – Jim Smith


In the last QNs issue, I spent some time talking about Computer Audio. I know that it hit home because I received more e-mail correspondence about that topic than any other QNs topics combined from the previous 5 QNs newsletters! When you think about our lives as audiophiles, more often than not we’ve had to go through more and more steps as our sound sources improved. I’ve called it the audiophile hair-shirt syndrome. We are all familiar with the whole process required for vinyl playback. It takes time and a lot of care to get the potentially great results that are waiting in those grooves. Watching me over the years, my wife would probably say it takes a good bit of compulsion.

Of course we all have to clean/coat/treat our CDs. Maybe even put a vibration-damping mat on each CD as we play it. There’s been a resurgence of high-performance reel-to-reel analog playback. Proper storage and handling of an analog tape is tedious (if you do it right). Then there’s tape head cleaning and demagnetization. Let’s be honest. As our potential for higher sound quality has grown, our audiophile hair-shirt has gotten itchier and itchier.

And that’s part of why Computer Audio is so unique and so relevant to our future as audiophile music lovers. For the first time that I can recall, a source technology (LP, CD, tape etc.) is easier to use while sounding noticeably better. When I say easier to use, I mean a lot easier to use.

The sound: Last issue I touched on the sound quality of Computer Audio. I purposely did not relate anything about some of the options available. The cool thing is that there are upgrade paths that you can take all without having to replace any hardware! For example what follows is my upgrade path. I’m not saying that it should be yours but I think it’ll be instructive info.

I initially used my MacBook Pro laptop with iTunes. I later introduced significant improvements without having to change any hardware (okay, I made a couple of changes to my MacBook because I didn’t have it optimized for Computer Audio when I ordered it – more about that in a moment). I didn’t have to change the laptop but I had read enough about the effects that I couldn’t resist doing it. If you remember the tip in GBS about making one change at a time, that’s what I did. But the first thing I did was to select a software program that would yield better sound than iTunes. There were a number to select from and the selection continues to expand. The two most widely used on the Mac platform are Amarra and Pure Music. 

I ended up choosing Pure Music. You might not. But a software system that can use the iTunes library—or maybe one that may not use it— can result in a rewarding upgrade in your sound quality if you’re playing Redbook CDs. If you’re still only a vinyl guy/gal, this new technology may cause you to rethink that position. I know it has for a number of my readers once they’ve been exposed to a higher level of performance from CD that is also far easier to use.

Better recordings, more involving sound: There is more and more music coming out and/or being remastered from high-res digital or analog originals. These 24-bit recordings with higher sample rates (88.2 or 96kHz) than the 44.1kHz CD, have an order of magnitude more information on them. This comes across as more detail in every area – music, low level info and enhanced spatial cues. Most importantly they have much greater musical dynamics not in the sense of being louder but in the area of going softer and retrieving more of the subtle sounds that have been lost with 16 bits. This greater resolution means that you will find your music playback to be more compelling, to be more emotionally involving than you’ve previously experienced from CD.

To play these recordings you need to find a special playback system. Standard Redbook CD players and transports won’t play them. What to do? Download them onto your computer from various sites such as Linn, HD Tracks, 2L etc. You’ll have near-master tape quality then. Furthermore you can also download exceptional masters from companies such as Reference Recordings at an even higher level of resolution. Gifted and accomplished recording engineers, some of whom I know, continue to report that 24-bit 176-or-192 technology is so good that they can’t tell it apart from the direct microphone feed at the recording session. The future is here!

Redbook CD: However, I’m writing this mostly to talk to you about making a significant improvement in your sound and the ease of using it when simply playing standard Redbook CDs that you already have or that are easily available. There are tons of articles that explain the advantages of importing an uncompressed bit-perfect recording into your computer. Once you have it, then you can decide what songs you want to keep and where you’d like to store them. With a little thought and careful selection, you’ll have a CD playback system that transcends what was possible from spinning discs in CD players and transports.

I am not recommending that you use the sound as it comes from your computer. There are no computers that have audiophile DACs in them. You’ll need a DAC. The computer becomes your transport, albeit a better source than a spinning disc.

There are good affordable DACs for computers to be had for no more than a couple of hundred dollars. An example is the HRT Music Streamer 2. As with most high-end audio, there are more costly DACS out there as well. From my research I ended up wanting to use the Ayre/Wavelength USB asynchronous streaming technology. The system had to be portable so I could carry it around North America to voice readers’ systems and to do demos in various locales. Since you’re reading this I know you have a computer and can use it well enough to get around on the Internet. As I mentioned last time, there is a lot of helpful set-up info on the Wavelength, Ayre and Computer Audiophile websites as well as others.

And the fact is, as a relative newbie to the world of Computer Audio, it turned out that I needed some help. But it was a one-time thing for each issue. As I got them resolved—again no biggie but it did take a bit of patience—all those problems went away and I’ve had no issues for several months. Well, maybe one issue. I don’t want to stop listening now…

Pure Music: Pure Music as delivered sounded great. It’s worth saying that any issues I ran into came about when I decided to take advantage of certain options in Pure Music. I could have left it 'stock' and all would have been well but I can’t seem to relinquish the notion of tweaking the system for a bit more. Resolving issues from my sometimes improper entry of some Pure Music tweaks, I always got prompt feedback from Channel D customer service. Channel D is the company that produces and supports Pure Music software.

Initially I took advantage of the free 15-day trial period to see if PM was worthwhile. It was. I should say again that you might prefer Amarra, AyreWave, J. River, Foobar or one of the other programs out there. Anyway, as I corresponded with the person who helped me, I noticed that his name was Rob, coincidentally also the name of the Director of Engineering at Pure Music. Sure enough, my help was coming from the top guy! One thing led to another and I discovered that Rob had bought a copy of Get Better Sound over a year earlier.

This interested me because I’ve long had an issue with some digital audio that was developed by smart people who seemed to have no interest whatsoever in high-performance audio. At least not at the level you and I have desired. At some point I asked Rob if I could interview him for an upcoming Quarter Notes. He agreed. This issue contains that interview.
Five easy pieces: These observations are about Computer Audio as a whole and only peripherally related to Pure Music:
(1) Ease of operation. This is a no-brainer. No discs or tapes to handle. No danger of scratching them or other wear and tear issues. In my absent-minded professor style, I’m always misplacing my music. Instead of searching through your source material for that music that you thought you knew where you’d left it, you just look into your computer list, select the music, push play and voilà! Also, I often only want to hear certain songs from an album. So I can store only those certain songs. Or easily select them with a mouse click.

(2) I was unprepared for the improved sound quality as I introduced some options that were available in Pure Music. Of course some of these options may also be available in other software programs. The cool thing is that you can try them out and see if you like them. If not, go back to what you had. No equipment to buy.  As upgrades come along in the software, the downloads are easy and they are free. No sending your component back to the factory for days or weeks. As a hard-core audiophile over the years, I can tell you that hardware upgrades are not free!

My little MBP/Ayre/Pure Music rig is simply better than the best CD playback I own, have owned or have ever heard. As I’ve voiced systems around North America, I’ve run into some systems with really sophisticated CD playback as well as excellent vinyl playback. In every instance the client has been struck by the compelling sound quality I get with every-day 16bit/44.1 music imported from standard CDs. It’s no exaggeration to say that some were literally dumbfounded. They had no idea that level of sound could be available from standard CD-sourced digital, not to mention that it came from a simple and relatively small portable rig. And every visitor to my place has had the same reaction. If you still haven’t dipped your toes into the Computer Audio water (and from the correspondence I get, at least half to two thirds of you haven’t), come on in. The water is mighty fine!

(3) Stumbling blocks. Yep there are some. I think some people who are not totally computer savvy will have a moment or two where they don’t understand how to make something work in the set-up. Please trust me here – it is totally worth the possible momentary frustrations to get another level of performance that is easier to access. And you may not have any troubles at all. Whichever software you select, I’d definitely start out with the stock music player program and use it for a while. Then if you’re so inclined, try some of the options. Some folks worry about the “time lost” importing their CDs. I haven’t found this to be an issue. I can do it while working. I can do it while watching TV or listening to music. I often do it while reading.

(4) Relative cost of upgrades – hardware vs. software. Pretty much of a no-brainer and one of the big advantages of Computer Audio.

(5) If only the CD had been conceived of, designed and supported by audiophiles. Fortunately we do have musically sensitive audiophiles on the digital design scene now so it’s a new day!

Computer hardware upgrades: I promised I’d mention a couple of upgrades that I did on my MacBook Pro. I should mention that I already had great sound. I didn’t need to do these upgrades. Anyway, here they are:

(1) More RAM. Easy to install and useful for a program that puts the music in memory if you choose that option. I had 4GB, which is a lot. But I added another 4GB because I had a slot and I was using the memory play option in Pure Music. I’m a Mac guy but I don’t buy their RAM. It’s too expensive. I used Crucial RAM. There are other options, which might be better or less expensive.

(2) I replaced my 7200RPM 500GB hard drive with a 256GB Solid State Drive (SSD). Again I didn’t buy the Mac product. I changed it myself. I used OWC Vertex. You may well prefer another option. 

You do need to do a little research before you do this regarding moving your operating system over to the SSD. I used Carbon Copy Cloner to do it. Didn’t even have to load my OSX software. Both of these tweaks improved my sound quality. Was it the proverbial night and day? No but I’m really glad I did it.

(3) Not an upgrade but I’m including it here – be sure you have a back-up system and that you use it!

The interview: Hopefully you know me well enough by now that you’re aware that I don’t specifically recommend products neither in the GBS set-up manual nor in Quarter Notes. What follows is not a specific endorsement or recommendation. It's simply useful to illuminate the direction Computer Audio is taking and maybe at least as important the direction from whence it came.

Meet Dr. Rob Robinson, Director of Engineering, Channel D
: Channel D offers a number of computer-audio-related software programs. In this case it’s their Pure Music software that introduced us to Channel D. Here’s a sort of bio that Channel D distributes: “Besides being an audiophile, musician and dedicated music lover, Rob Robinson was a research scientist and project manager at Bell Communications Research (originally part of AT&T Bell Laboratories) in New Jersey. Dr. Robinson has been designing application and driver level software for the Apple Macintosh platform since 1985, focusing on audio signal processing and analysis. He has been responsible for product creation at Channel D since 1996. Starting with the introduction of the acclaimed Mac the Scope audio signal analyzer in 1997, Channel D has created popular and innovative audio software for Apple Macintosh computers. Pure Vinyl released in 2006 for transcription of vinyl LPs to high resolution digital formats was recently honored with a Stereophile Product of the Year Award. Pure Music high-resolution digital audio player software released in 2010 has been praised by audiophiles worldwide.”

Jim - How long have you been interested in high-performance consumer audio?

Rob - Since about 1973 when I designed and built my first subwoofer which used a Dahlquist passive crossover until I learned to build my own active crossovers. It was a folded quarter-wave transmission line, a fairly large box that played quite loudly. Rock concert loud. It's hard to imagine now but this was way before the notion of a subwoofer had entered the consciousness of audio consumers in general. A subwoofer was really quite a weird thing to have back then even for an audiophile. I designed and sold subwoofers with internal power amplifier and crossover while in graduate school to student colleagues and even to one of my professors! This continued for some time afterwards. Somehow my future co-workers also caught wind of my interest in audio and I either sold them my subwoofers or consulted on audio systems. That was in the 1980s.

Jim - What kind of system do you have now?

Rob - My personal systems include loudspeakers by Vandersteen, PSB, Polk, Cerwin-Vega (for playing very loud in a big room) and JBL (mini speakers in a patio) plus eight Bag End subwoofers (I don't have the time to design and build subwoofers any more). Power amplifiers are by Parasound, Hafler, QSC and Jolida. No analog preamplifiers at all except for a couple of Channel D Seta 'flat' phono stages. I also have a couple of DAT machines and cassette recorders for transcribing old tapes. My analog linestage preamplifier has been collecting dust since 2000 when I set up my first dedicated 'computer audio' system.  Right now my favorite audio interfaces for my main system are the Lynx Aurora 8 or the Prism Orpheus connected to a Mac Mini.

All components are connected together in a distributed audio system streamed (using Pure Vinyl software's NetSend feature) to remote Mac computers and DACs over wired Ethernet. The main system or any of the remote computers can drive all of the (other) remotes with the same audio source. The remotes are time-aligned with software on the receiving computer so that when walking from room to room the sound holds together coherently without any echoes. This would not happen if it were not time-aligned. The effect is really quite liberating because there is no 'beaming' of audio from any one system. It simply and effortlessly fills the entire living space while still permitting critical focused listening in the main listening room with the primary system.

Jim - Do you have a turntable?  

Rob - Of course! Four turntables (a 5th is planned relatively soon) by Michell, Thorens, Pro-Ject and Technics. I've also owned other turntables including Dual, Garrard and Rabco (the linear tracker). I use the Technics for playing 78s and the Pro-Ject for certain thrift store records when I don't want to risk damaging the styli on my better cartridges. Cartridges include Ortofon Kontrapunkt b and Ortofon A90 moving coil, plus Grado, Ortofon and Audio-Technica moving magnet on the other tables. All of this gear was paid for, none 'donated' by manufacturers. I have long stopped counting LPs but my LP collection covers well over 50 linear feet so over 5000 in every genre of music, plus several hundred 7" 45 singles. Also about 1500 CDs with not that much overlap with the vinyl.

Jim - What prompted you to develop the PM product?

Rob - This was an outgrowth of the Pure Vinyl product we introduced in 2006. So to discuss Pure Music also means discussing its Pure Vinyl roots. The enabling technology for Pure Vinyl and our computer audio software products was the introduction of the Lynx TWO 192kHz 24-bit sound card around 2001. I think it still ranks among the best. I thought I would attempt RIAA correction in the digital domain with this card and the results even with a simple bread-boarded gain stage were astonishing. It later turned out that the microphone preamps included with many audio interfaces used for recording were a good match in terms of gain and noise level for lifting the signal level of a MC cartridge.

This was confirmed with blind tests. We compared high-quality (that is properly mastered, not 'loud') CD issues of the same vinyl recording—carefully level matched of course—with the different recording sources/tracks alternated on a CD-R disc to eliminate as many variables as possible. The subjects in the blind test knew the purpose of the tests but were floored when told that the 'better' ones they picked were actually sourced from vinyl, not CD!

So we took on a tremendous risk of beginning development of Pure Vinyl in 2002 strictly out of love for the analog format. At the time vinyl was dead commercially and so we stood little to gain financially from this venture. It was a little crazy to attempt it but the improvement in quality from the digital RIAA compared to a conventional phono stage made it worthwhile. From 2002 to 2006 we fine-tuned and honed the entire signal chain, optimizing and streamlining performance in conjunction with extensive listening tests and living with and using the product on a daily basis. Pure Vinyl 1.0 was released in 2006 after 4 years of development and testing.

In Pure Vinyl 2 released in 2008 we added a feature to allow automatically grabbing and playing tracks from iTunes playlists. This was the beginning of Pure Music. In the next iteration of Pure Vinyl we added the iTunes 'docking' and window tracking interface. This immediately grabbed the attention of audiophiles with computer audio systems. The playback quality was praised beginning with the very first adopters. Folks actually were buying Pure Vinyl just for this feature and ignoring the 'vinyl' recorder part!

So the next logical step was to create a product containing only the player features in Pure Vinyl. That product was Pure Music introduced at the AXPONA audio expo in March 2010. It was an immediate success. The parts of the software dealing with vinyl recording etc. are actually completely stripped out of Pure Music and not simply disabled with a software flag. And regarding the Pure Vinyl product, of course now there seem to be other products arriving for vinyl transfer to digital if only to capitalize on the demand for such things. But we actually blazed the first trail purely out of dedication to and a love for the medium.

Jim - In your opinion what is in the digital future for audiophiles?

Rob - I went over this a bit in my presentations at RMAF in the Vinyl Ripping and Advances in Computer Audio seminars in which I participated or conducted the primary presentation. Basically if it hasn't already happened it will very soon. Except for vinyl and perhaps SACD, computer audio will make everything that's connected before the audio system power amplifiers obsolete. The sound quality of the latest high-resolution audio converters is indistinguishable from pure analog so we can now also replace the line-level preamplifier with a multi-channel input audio interface using software for source switching and volume control, providing a virtual line-level preamplifier.

Jim – Hmm. Not sure I’m ready to make this jump just yet. I only just got my feet nice and wet with Computer Audio.  And it’ll take amplifier manufacturers willing and able to incorporate the high-res digital inputs. But we’re talking about the future for audiophiles even though a good bit of it is possible now, maybe all of it. I can’t imagine handling the music with a system of less than 24/192 capability if not 32/384. As I‘ve mentioned, most perceptive recording engineers report that they can hear the difference between a direct mic feed and 24/96 but not with 24/192. So we’ll want to use a system that is totally transparent and one that doesn’t lose critical resolution when we turn it down. Do you have access to any numbers showing the penetration of computer audio into the CD realm? How about a best guess?

Rob - I will say—without getting into specifics or climbing out on a limb in the spirit of anyone's favorite weather prognosticator—that it's less than 50%. 

Jim - Will we still be able to buy CDs in 7 years?

Rob - Yes.

Jim - Maybe you’re right. I can’t imagine it hanging on for long. Any other similar topics that you'd like to expound upon, or for that matter any soapbox you'd like to speak from?

Rob - I shared some of my thoughts on the topic of why computer audio sounds good and why there are sonic differences between what are deemed bit-perfect audio software players at the Advances in Computer Audio seminar at the past RMAF. (I believe they will be posting the videos of the sessions in a month or so.) It is a slightly complicated topic but I will state up front that it is definitely not because of the math or integer to floating point to integer conversion etc. That stuff is not rocket science. For example Apple specifies exactly how it is to be done. There is only one correct way. It's true that some hardware and software manufacturers tried to be a little too clever with the conversion process when Mac OS X was first introduced many years ago. This ended up actually harming the audio quality because of conflicts in the way the conversion was expected to be performed. But that's a thing of the past now.

The real reason for differences in quality has more to do with the degree of code streamlining, keeping data pipelines filled and flowing as smoothly as possible. Bits are only bits except when we are talking real-time delivery of audio because the temporal aspect, the business of actually delivering the bits to the hardware, is critical. The temporal aspect can be influenced by things like periodic surges in power demand affecting the signal reference levels in hardware even in the digital domain. A computer works most efficiently and draws power more steadily and smoothly under balanced steady-state load conditions, not when surges in CPU demand are continuously interspersed with idle states while the audio is playing. Things like memory play are helpful but the underlying framework has to be there to derive the most benefit from it.

Jim – More and more products are coming out. Any opinion?

Rob - If you mean products like new models of optical disc transports for CD audio, sadly their days are numbered. Aside from that I don't know what other products you mean?

Jim - I meant more interesting software products like AyreWave, Audirvana etc.

Rob - The newer ones on the Mac platform are beginning to learn how difficult it can be to deliver something that works reliably and consistently for all users, even just a bare-boned player having a minimal user interface. We've been there, done that and consistency is key in this new computer audio thing. We want to make audiophiles happy in taking this route.

Jim – It does seem that some of the newer programs assume a certain familiarity with Computer Audio. I don’t think this is necessarily a bad thing. 

Rob - Some additional perspective: we use iTunes as the controller and library manager because we've seen many 'stand alone' (that is, trying to keep separate from iTunes) music player software packages that attempt to directly parse the iTunes database format come and go over the years. Go because Apple sooner or later decides without warning to change the iTunes database format, breaking the third party player software.

Jim – Hmm. This can sound daunting to a complete Computer Audio newbie as I was maybe six months ago.  After all of this, I want my readers to fully embrace this exciting new future in audio and not be scared to try it. 

Rob – Well, you got through it and you admit to not having had much of a clue! -:) FWIW, we have users that have never used a computer before and are helping them through computer 101. For example, basics such as how to shut down the computer are unknowns. We now have a Getting Started section on the website, which is continually being honed, updated and revised.

Jim – Thanks Rob. This interview has me even more excited about Computer Audio because the main man at Channel D came out of a near life-long love affair with analog, which he still enjoys to this day! And the good news is that I can think of many more visionary designers in the hardware field who are making the transition but always carrying their analog values with them.